Rozprawy doktorskie: „Native fish”

1

McGinley, Susan. "Tagging Fish: Monitoring Native Species". College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2000. http://hdl.handle.net/10150/622273.

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Gandy, David A. "Examining Gradients in Novelty: Native and Non-native Fish Assemblages in Everglades Canals". FIU Digital Commons, 2013. http://digitalcommons.fiu.edu/etd/951.

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Novel ecosystems emerge from alterations to historic abiotic regimes and contain new species combinations. Everglades canals offer an opportunity to understand the function of novel habitat for native and non-native fishes and how novel conditions in turn influence distribution, abundance and assembly patterns. I examined native and non-native fish assemblages collected across a gradient in novelty, defined by the loss of wetland connectivity and habitat complexity. As novelty increased, native species richness and abundance strongly declined, and the contribution of non-natives increased. Community structure vastly differed among canals and was strongly influenced by spatial factors and secondarily by hydrological factors. Natives and non-natives had opposing responses to key hydrologic and habitat parameters. This study represents the first comprehensive assessment of Everglades canal fishes, providing insight into the factors influencing native and non-native abundance and assembly patterns and contributing to our understanding of this novel but permanent habitat.

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3

Rinne, John N. "Nonnative, Predatory Fish Removal and Native Fish Response, Upper Verde River, Arizona: Preliminary Results". Arizona-Nevada Academy of Science, 2001. http://hdl.handle.net/10150/296582.

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4

Zipfel, Katherine J. "The distribution and status of native walleye (Sander vitreus) stocks in West Virginia". Ohio : Ohio University, 2006. http://www.ohiolink.edu/etd/view.cgi?ohiou1164229538.

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5

Rinne, John N. "Relationship of Fine Sediment and Two Native Southwestern Fish Species". Arizona-Nevada Academy of Science, 2001. http://hdl.handle.net/10150/296569.

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6

Monopoli, Matthew Stephen. "Acid water tolerance in a New Zealand native freshwater fish". Thesis, University of Canterbury. Zoology, 1996. http://hdl.handle.net/10092/6974.

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Physiological experiments were conducted to measure the effects of low pH water upon Na⁺ fluxes and swimming performance in east coast neutral water banded kokopu, and west coast banded kokopu living in naturally acid water. This allowed comparisons to be made regarding the relative acid tolerance between the two population stocks. A morphological study of the gills using scanning electron microscopy and transmission electron microscopy was carried out on a limited number of fish to compare gill structures of east coast acid and non acid exposed fish with west coast fish. East coast kokopu from neutral water showed a reduced sodium influx on the first day of exposure to pH4 water. This was accompanied by a reduction in passive loss or efflux. After 4 days at pH4 influx recovered allowing the fish to approach sodium balance. West coast fish showed no significant change in influx upon introduction to pH7 water and maintained influx values in pH4 water near those measured for control fish. For east coast fish, swimming performance was significantly impaired on the 2nd swimming trial when pH was lowered from 7 to 4. On the third swim with the pH returned to 7, Ucrit was similar to the initial value. West coast banded kokopu showed a significant increase in performance between trial one and three and were unaffected by pH7 water, matching performances measured in control fish. Gills from east coast acid exposed fish resembled west coast fish in that the trailing edges of the lamellae were swollen due to the large numbers of chloride cells which were present to a point approximately half way up the lamellar edge. Microridges were present on the apical surfaces of the chloride cells of east coast control fish which contrasted with the microvilli structures observed in west coast and acid exposed east coast fish. The microvilli structures present on the chloride cells of west coast and east coast acid exposed banded kokopu appeared to assist in the anchorage of mucus to the apical surface of the cell.

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7

Ingram, Brett A. "Rearing juvenile Australian native percichthyid fish in fertilised earthen ponds". Connect to this title online, 2001. http://tux.lib.deakin.edu.au/adt-VDU/public/adt-VDU20050418.172221/.

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8

Esplin, Lindsay D. "Culvert Roughness Elements for Native Utah Fish Passage: Phase I". BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2506.

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Culverts can increase stream velocities as a result of reduced waterway areas and prevent upstream passage of small non-salmonid fish such as the Native Utah Leatherside chub (Gila copei) and Longnose dace (Rhinichthyscataractae). To mitigate this problem, current culvert design standards for fish passage match sustained fish swim speeds with average cross sectional velocity through the culvert. Such policies dictate relatively large barrels and do not recognize the role of reduced velocity zones near culvert boundaries. Obstacles and streambed substrate create turbulent regions with lower velocity zones that can increase upstream fish passage. A comparison of upstream passage success using native Utah fish in an experimental flume was conducted with three different conditions: (1) a smooth boundary, (2) a smooth boundary with strategically placed cylinders, and (3) a boundary consisting of natural substrate. The refuge provided by the cylinders and substrate allowed fish to expend less energy as they swam upstream. Energy expenditure was compared between the conditions by mapping the velocity field near the boundary and tracing fish swim paths. Substrate provided sufficient refuge for the fish to behave in a manner similar to their behavior in a natural environment and with significantly reduced energy expenditure. Cylinders provided limited refuge that allowed fish to rest periodically as they navigated the flume. The smooth boundary case required the highest energy expenditure as there was no refuge provided. Fish swimming capabilities in the form of prolonged and burst velocities have been recorded for most species. Streamwise velocity near the boundary can be compared to the prolonged and burst swim speeds to predict passage rates. Further field testing is necessary to fully substantiate the effectiveness of utilizing reduced velocity zones in non-salmonid fish passage prediction. If such a design approach can be used instead of using the conservative but overly simplistic average velocity to evaluate the retrofit of existing culverts and to design new culverts it will help minimize costs and result in fewer culvert replacements and smaller and simpler new designs. Other implications such as downstream effects on stream bed stability and scour remain an issue.

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9

Monk, Suzanne Kim. "Culvert Roughness Elements for Native Utah Fish Passage: Phase II". BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3656.

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Native fishes have become an increasingly important concern when designing fish passable culverts. Many operational culverts constrict waterways which increase velocities and prevent upstream passage of small fish species. The current method to ensure fish passage is to match the average cross sectional velocity to the sustained swim speed of the fish. This study investigates the passage rates of leatherside chub (Lepidomeda aliciae) and speckled dace (Rhinichthys osculus) at three sites (an arch culvert with substrate bottom, box culvert with bare bottom, and a stream section with no culvert) located on Salina Creek near Salina, UT. It was found that fish were able to pass through all of the sites. However, fish were able to take advantage of the habitat within the culvert that had a substrate bottom more effectively than within the culvert that had no substrate within the barrel. This was reflected in population density estimates at each of the three test sites for each species. It was also found that the substrate at the arch culvert and stream sites scaled with the fish measured in this study. The D50 and D84 were 44 and 205 mm at the arch culvert site and 26 and 126 mm at the stream site. The average fish length was 76 mm for the chub and 64 mm for the dace. It is recommended that (1) a culvert size that produces a velocity equal to the prolonged swim speed of target fish in the near boundary region (2 cm above the bed) be used in the future, and (2) substrate that scales with the target fish species be placed in the culvert barrel.

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10

Snyder, Claire. "A microchemical analysis of native fish passage through Brandon Road Lock and Dam, Des Plaines River, Illinois". OpenSIUC, 2019. https://opensiuc.lib.siu.edu/theses/2601.

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Modifications to Brandon Road Lock and Dam (BRLD), located on the Des Plaines River in northeastern Illinois, have been proposed to prevent the upstream transfer of aquatic invasive species, particularly Asian carps, into the Great Lakes Basin. These modifications, including the installation of an electric barrier, acoustic fish deterrent, and air bubble curtain, are designed to completely eliminate all upstream fish passage and may negatively impact native fish populations in the Des Plaines River by reducing upstream movement and potentially fragmenting populations. BRLD is situated just 21 km upstream of the Des Plaines River mouth, and fish are only able to pass upstream via the lock chamber. Fish species richness within the Des Plaines River watershed has increased over the last 35 years. It has been suggested that the majority of new species to the upper Des Plaines River have migrated upstream past Brandon Road Lock and Dam (BRLD), from the Illinois, Kankakee, and lower Des Plaines rivers. However, documentation of emigration needed to support that contention is lacking and there is limited knowledge of the current rate of BRLD passage by native species. To assess native fish passage through the lock, a microchemical study was conducted using fin rays from fish collected from the Des Plaines, Illinois, and Kankakee Rivers. The edge of each fin ray, which contained the most recently deposited material, was assumed to contain a microchemical signature reflective of residency in the river where the fish was sampled. Fin ray edge strontium:calcium ratio (Sr:Ca) was used to define taxonomic and river-specific signature ranges for four taxonomic groups: centrarchids, catostomids, ictalurids, and lepisosteids. Fin ray edge Sr:Ca data were input into a random forest classification model, and the classification accuracy of fish to their river of capture based on their fin ray edge Sr:Ca was > 97% in each taxonomic group. The classification model was then applied to the entire fin ray of each fish sampled upstream of Brandon Road to infer retrospective environmental history. Upstream BRLD lock passage was suggested by the presence of Sr:Ca signatures indicative of prior downstream residency in the Illinois or Kankakee rivers in a fish sampled upstream of BRLD. Results indicated some evidence of downstream residency that suggested upstream BRLD lock passage for centrarchids, catostomids, ictalurids, and lepisosteids, ranging from 15 – 37% of individuals sampled depending on taxa. An additional 19 – 80% of individuals within each taxonomic group were classified as fish with uncertain downstream residency, whereby the possibility of BLRD lock passage could not be rejected, but there was higher uncertainty in establishing downstream residency in the Illinois or Kankakee rivers. The impact of BRLD modifications and passage restriction on Des Plaines River fish populations is unknown and merits further investigation.

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11

Barrientos, Christian Alberto. "Fish abundance and community composition in native and non-native littoral aquatic plants at Lake Izabal, Guatemala". [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0012100.

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12

Hedden, Skyler C. "Movement and consumptive demand of the introduced flathead catfish Pylodictis olivaris in the upper Gila River basin, New Mexcio, and potential impacts on native fishes". Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/20492.

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Master of Science
Biology
Keith B. Gido
Negative interactions with nonnative fish are often cited as a leading cause of declining native fish populations, but quantifying these interactions is difficult. Movement ecology and consumptive demand estimates of nonnative fish predators is needed to better understand potential impacts these organisms are having on native species. The objective of this thesis were to estimate the consumptive demand of Flathead Catfish Pylodictis olivaris on native fishes across an elevational gradient, and characterize the movement at hourly, daily, and seasonal scales of this introduced predator. This research was conducted in the upper Gila River basin of southwestern New Mexico. Bioenergetics modeling was used to estimate consumptive demand; model results were coupled with measured densities and size structure of Flathead Catfish populations, and water temperatures, to predict its predatory threat. Potential consumption was highest at lower elevation sites because of higher water temperatures, but actual consumption was highest at mid-elevation sites because of the prevalence of large-bodied individuals. Potential annual consumptive demand of Flathead Catfish on native fish across our nine sampling sites ranged from 0.0 to 3.1 g/m²/yr, which exceeded native fish productivity at one site. To characterize the movement of Flathead Catfish, we used radio telemetry and tracked individuals from May 2014 to June 2015. Movement behaviors varied among individuals with a majority moving <150 m from capture location and some more mobile, moving substantial distances (692-42,840 m). During the course of the study, activity was greatest in summer and fall, and individuals moving substantial distances moved downstream to warmer river reaches before the winter. Nightly movements only involved short distances (5 m) and no fish exceeded a single movement >80 m. Daily activity was greatest during evening but late afternoon activity was observed in summer and fall. Results from this study identify areas within the upper Gila River where introduced Flathead Catfish consumption is likely to negatively impact native fish populations and managers can use this information to understand potential overlap with native species, target future removal efforts in areas where these fish are concentrated, and avoid stocking native fishes in reaches where Flathead Catfish tend to aggregate.

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13

Bellgraph, Brian Joseph. "Competition potential between sauger and walleye in non-native sympatry historical trends and resource overlap in the middle Missouri River, Montana /". Thesis, Montana State University, 2006. http://etd.lib.montana.edu/etd/2006/bellgraph/BellgraphB0506.pdf.

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Thesis (M.S.)--Montana State University--Bozeman, 2006.
Title from PDF t.p. (viewed on Mar. 30, 2008). Chairperson, Graduate Committee: Christopher S. Guy. Includes bibliographical references (p. 65-72).

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14

Howard, Simon William. "Flow-related threats to rare galaxiids in the upper Waitaki River". Thesis, University of Canterbury. School of Biological Sciences, 2014. http://hdl.handle.net/10092/9976.

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Human activities are increasingly altering ecosystems, and are especially severe in streams where flow modification can affect environments far downstream and can interact with other pressures, such as species invasions. This has led to a disproportionately high number of threatened species in streams (e.g., native galaxiid fishes in New Zealand). I investigated how threatened bignose galaxias (Galaxias macronasus) and upland longjaw galaxias (Galaxias prognathus) were affected by flow-related influences in their habitats. A survey of sub-catchments in the Mackenzie Basin showed that flow regulation played a strong role in influencing fish occurrence; native fishes dominated unregulated rivers and introduced species dominated regulated rivers. Upland longjaw galaxias (ULG) were sparsely distributed and only found in unmodified braided rivers. Targeted surveys in these rivers indicated their habitat selection was weak, and although habitat availability was high, individual habitats were only occupied for short periods because floods frequently reconfigured the river bed. Thus, disturbances played a major role in ULG populations, forcing a strategy of weak habitat selection and frequent movement. This also makes them vulnerable to large-scale flow changes making the habitat more benign and potentially increasing competition (e.g., from invasive trout). Bignose galaxias were only locally abundant in very low discharge habitats lacking other fishes, so were restricted to very small parts of the river network. An experiment manipulating flows showed bignose galaxias moved into slower habitats over the short-term, suggesting a slow-flow preference, but not excluding the competitive influences of other fish like trout. Overall, this work shows these threatened fishes are susceptible to many of the current and future global changes affecting freshwaters like habitat alteration and invaders, but the above knowledge should allow targeted management of these influences for these highly threatened endemic fish.

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15

Whitehead, J. Andrew. "Proximate and long-term effects of agricultural pesticide runoff on native fish /". For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2003. http://uclibs.org/PID/11984.

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16

Ellender, Bruce Robert. "Ecological consequences of non-native fish invasion in Eastern Cape headwater streams". Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/69065.

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The introduction, spread and concomitant impacts of non-native species are a global problem. Fish are among the most widely introduced vertebrate groups, with their impacts affecting multiple levels of organisation- from individuals, populations and communities, to entire ecosystems. In South Africa, the largest perceived threat to range-restricted endemic headwater stream fishes is said to be invasion by non-native fishes, however, as is the case elsewhere, invasive impacts are often a case of risk perception rather than actual risk analysis. Two range-restricted headwater species, the Eastern Cape redfin Pseudobarbus afer and the Border barb Barbus trevelyani are redlisted by the International Union for the Conservation of Nature (IUCN) as ‘Endangered’, primarily due to invasion by non-native fishes. To investigate invasions in South Africa, and provide a quantitative estimate of the impact of non-native fishes on the two imperilled endemics, P. afer and B. trevelyani, the overall aims of this thesis were to: (A) Provide a literature review on non-native fish invasions in South Africa; (B) Using two case studies on the headwaters of the perennial Keiskamma and episodic Swartkops River systems, investigate the naturalisation-invasion continuum to provide a holistic view of the invasion process in these variable environments. The specific thesis objectives were: (1) Reviewing current knowledge of invasive impacts of non-native fishes in South Africa; (2) Investigating invasibility of headwater stream environments by non-native fishes; (3) Determining the establishment success of non-native fishes, (4) Assessing the spatial and temporal impacts of invasion; (5) Understanding mechanisms responsible for non-native fish impacts; (6) Investigating the threat of non-native fish invasion on the genetic diversity of two the two headwater fishes, P. afer and B. trevelyani. Results from the literature review of fish invasions (Chapter 1) showed that South Africa has a long history of non-native fish introductions, spanning two and a half centuries. Currently, 55 species have been introduced or translocated. Many of these introduced species have become fully invasive (36%). Their impacts also span multiple levels of biological organisation. There was a general paucity of studies on fish invasions (38 studies), however, of those conducted, reviewed studies placed emphases on invasive impacts (25 studies) and the transport, introduction, establishment and spread stages of the invasion process were largely ignored. The two study systems, the Swartkops and Keiskamma Rivers, were heavily invaded and numbers of introduced species surpassed that of natives (Chapter 2, 3 and 5). Headwater streams had varying invasibility and a number of non-native species were successfully established (Chapter 2, 3, 5 and 6). The remainder of the invasions were casual incursions into headwater streams from source populations in mainstream and impoundment environments which were invasion hotspots. Irrespective of establishment, four predatory invaders (largemouth bass Micropterus salmoides, smallmouth bass M. dolomieu, brown trout Salmo trutta and rainbow trout Oncorhynchus mykiss) impacted heavily on native fish communities (Chapter 3, 4 and 5). Two broad types of invasion were documented, top down invasion by non-native O. mykiss and S. trutta and upstream invasion by M. salmoides and M. dolomieu (Chapter 3 and 5). Their impacts included changes in community structure, extirpation from invaded stream reaches resulting in contracted distribution, and isolation and fragmentation of native fish populations. The impacts of non-native predatory fishes were particularly acute for P. afer and B. trevelyani. Where non-native predatory fish occurred, P. afer and B. trevelyani had been extirpated (Chapter 3 and 5). As a result both native species exhibited contracted distributions (>20% habitat loss due to invasion). Upstream invasion by centrarchids isolated and fragmented P. afer populations into headwater refugia, while top down invasion by salmonids excluded B. trevelyani from invaded, more pristine stream reaches, by forcing the species into degraded unsuitable lower stream reaches. Predation also disrupted population processes such as adult dispersal for P. afer, and centrarchid-invaded zones acted as demographic sinks, where adults dispersing through invaded reaches were rapidly depleted. While the Mandela lineage of P. afer exhibited little within or between drainage genetic structuring, B. trevelyani was >4% divergent between drainages, and up to 2% divergent between streams within the Keiskamma River system (Chapter 7). The distribution of genetic diversity for B. trevelyani also indicated that the loss of diversity was imminent without immediate conservation interventions. This thesis has provided conclusive evidence that native fishes are vulnerable to invasion and that non-native predatory fishes have significant impacts on native fishes in Eastern Cape headwater streams. If management and conservation measures are implemented, the unwanted introduction and spread of non-native fishes may be restricted, allowing native fishes opportunities for recovery.

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McLeish, Jenny. "Non-native bullhead in Scotland : molecular and morphological identification and parasite links with native fauna". Thesis, Edinburgh Napier University, 2018. http://researchrepository.napier.ac.uk/Output/1253308.

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The arrival of a non-native species to has the potential to shape native communities by influencing ecological interactions such as predation, foraging, competition and disease transfer. A designation of invasive is applied to an introduced non-native species that has the potential to threaten the continued wellbeing of a native species, pose a risk to human health or negatively impact the economy. The European bullhead (Cottus perifretum) is a freshwater benthic-dwelling fish that is native to England but considered invasive in Scotland. The species was first reported in Scotland in the 1950's and thriving populations are now established in the waters of the Clyde, Forth and Tweed catchments. Bullhead presence is thought to negatively impact native stone loach (Barbatula barbatula) and brown trout (Salmo trutta) parr, due to shared preferences for habitat and prey resources. They are also thought to prey upon the eggs of native Atlantic salmon (Salmo salar) and brown trout, two species that are of high commercial value in Scotland. In other areas of introduction, bullheads have been found to increase parasite infection rates in native fishes. The species therefore has the capacity to incite competition and alter parasite/host interactions in areas of introduction, to the potential detriment of native fauna and the Scottish economy. The European bullhead has been the subject of considerable taxonomic scrutiny in recent years, resulting in its reclassification as a species complex. What was once considered a single species with a distribution encompassing Europe, Russia, Asia and Scandinavia, has been shown to consist of at least 15 distinct species. Genetic examination of bullheads from England confirmed the presence of Cottus perifretum, not Cottus gobio as traditionally listed in all UK literature and legislation. Native English bullhead is currently protected under Annex II of the European Commission Habitats Directive 92/43/EEC, based on the historic assumption that the species present is C. gobio. Analysis of the taxonomic identity of Scottish bullheads has remained outstanding. In this study the invasive status of bullhead was explored by examining feeding and parasitological interactions between bullheads and native freshwater communities in south-east Scotland. An assessment of the feeding preferences of native brown trout and stone loach in the presence and absence of bullheads tested competition for prey resources. Parasitological interactions were investigated by examining the shared parasite fauna of bullheads and native fish and invertebrate species. Bullheads from the Clyde and Forth catchments were analysed to provide a molecular and morphological description of this introduced species. Phylogenetic analysis of COX1 sequences obtained from Scottish bullheads, and a pair-wise distance calculation based on a Kimura 2-parameter model, showed that samples clustered in a distinct clade with English C. perifretum. Significant intraspecific variation was reported in all morphological features examined, but pooled data also revealed a resemblance to the published description provided for C. perifretum. Scottish bullhead is therefore confirmed to be an introduced pocket of the native English species, which is considered under threat in some areas due to habitat modifications and population decline. Comparisons between the dietary compositions of bullheads, brown trout and stone loach showed that the prey selection of brown trout and stone loach varied in the sample locations that contained co-occuring bullheads, when compared to locations where bullheads were absent. However, no direct evidence of trophic competition between bullheads and either brown trout or stone loach was reported. An examination of parasitological interactions recovered eight parasite species from four distinct taxonomic groups in total, of which four species (Echinorhynchus truttae, Apatemon gracilis, Diplostomum volvens and Raphidascaris acus) were shared between bullheads and one or more native fishes. Echinorhynchus truttae was also shared with gammarid crustaceans. Bullhead presence was found to coincide with D. volvens infections in European minnow (Phoxinus phoxinus) and a reduced prevalence of E. truttae in brown trout. Diplostomum volvens was only reported from minnow found in sites with bullheads, strongly suggesting bullheads were responsible for introducing this parasite to native minnows. Bullheads functioned as an alternative host for E. truttae, diluting brown trout parasite loads and reducing overall infection rates in sites where bullhead and brown trout co-exist. The findings reported for both feeding preference and parasite burdens in the presence and absence of bullheads suggest that bullheads do have some effect on the ecology of native species, but these are considered minimal and unlikely to impact the long-term survival of native species. Eradication of Scottish bullhead may contradict the conservation effort that is currently in place. Given the current lack of evidence to validate bullhead's invasive qualities and the recent confirmation of its genetic lineage, revisiting the designation of the bullhead as invasive is warranted. Active eradication should be treated with caution until a significant negative impact can be proven.

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Larish, Penny Mae. "An analysis of fish consumption in Winnipeg with identification of potential niche markets for freshwater fish species native to Manitoba". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0007/MQ41661.pdf.

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Harford, Andrew James, i andrew harford@rmit edu au. "The characterisation of Australian freshwater fish immune systems and their response to immunomodulators". RMIT University. School of Medical Science, 2005. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20060307.171411.

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The Murray-Darling basin is the largest river system in Australia with significant economic, social, recreational and cultural value. It supplies water for drinking and agriculture to a large inland area of the eastern and southern states of Australia. It is also the ultimate sink for many environmental contaminants that result from human activities within the catchment. Aquatic organisms live intimately with their environment and may be continuously exposed to these contaminants through the water column or the food chain. Some chemicals are bioaccumulated and biomagnified in tissue to reach high body burdens. Populations of native fish species within the Murray-Darling basin have been in decline since human settlement, yet little is known about the lethal and sublethal effects of environmental pollutants on native freshwater fish and many of the Australian water quality guidelines are based on data from exotic fish species. Researchers have correlated levels of pollution with immune dysfunction and an increased incidence of disease amongst wildlife populations. Many of the pollutants of the Murray-Darling basin have known immunotoxicity in both mammals and exotic fish species. The immune system is a sensitive target organ because, in order to maintain integrity, it requires constant renewal through the rapid proliferation and differentiation of cells. Efforts to increase numbers of native fish in the wild have led to an aquaculture industry that produces fingerlings for the restocking of waterways. In more recent years, this industry has matured and now produces table-size native freshwater fish for local and international markets. Although the industry has researched areas of reproduction, nutrition and stocking, there is little understanding of the immunology or immunotoxicology of Australian freshwater fish. This research project investigated the immunology of three large native fish species (i.e. 2 Murray cod, golden perch and silver perch), which are the basis of the native freshwater aquaculture industry. Additionally, a small fish species native to the basin (i.e. crimsonspotted rainbowfish) was studied as an alternative to the use of large fish. Of the four species, Murray cod possessed characteristics that made it an excellent candidate for ecoimmunotoxicity testing.

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Gevertz, Amanda Kate. "Differential tolerances to ultraviolet radiation and fluoranthene exposure: Comparisons between native and non-native fish of Lake Tahoe (CA/NV)". Miami University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=miami1280515882.

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21

Rinne, John N., i Brian Deason. "Habitat Availability and Use by Two Threatened Native Fish Species in Southwestern Rivers". Arizona-Nevada Academy of Science, 2000. http://hdl.handle.net/10150/296553.

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22

Eikaas, Hans Skailand. "The effect of habitat fragmentation on New Zealand native fish : a GIS approach". Thesis, University of Canterbury. Environmental Science, 2004. http://hdl.handle.net/10092/5963.

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Land use change is likely to have influenced the distributions of adults of the New Zealand galaxiid fishes (family Galaxiidae) with life histories involving a juvenile migratory 'whitebait' stage. The influence of interactions between these diadromous migrations, terrestrial habitat fragmentation, migratory barriers and local habitat conditions on the distribution ofkoaro, inanga, and giant, shortjaw and banded kokopu were investigated using a geographical information system approach. A catchment-scale analysis of Banks Peninsula streams with riparian forest indicated position and extent of forest explained 65.7% of koaro occurrence. When riparian forest was lacking koaro were rare and catchment variables had no influence. A site-scale analysis using logistic regression predicted koaro and banded kokopu presence at > 80% of sites using land use-related variables. Hindcast and forecast models showed that both species likely occupied over 85% of available stream habitat in 1860. Reforestation would have differential effect on koaro and banded kokopu depending on forest position. Banded kokopu, a forest specialist, was affected by edge effects of forest fragmentation, occurring in larger numbers and sizes in forested streams, whereas koaro was affected by catchment forest cover. A large-scale study of migratory galaxiid occurrences on South Island's West Coast indicated maximum slope encountered during upstream migrations was a good predictor of fish occurrence, and species had different slope-thresholds. A hierarchical analysis that differentiated between abiotic barriers, migratory passage, and land use impacts on fish occurrence showed that land use impacts on the migratory passage was the major factor limiting migratory fish distributions. This research shows that migratory galaxiids are sensitive to the configuration of landscape elements and migratory barriers, factors that can be used in predictive models to differentiate and quantify distribution limitations due to migratory passage, catchment land use, and local habitat conditions. The approach is useful for managers because it is robust, feasible, and transferable to other migratory fish species.

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Howard, Simon William. "Effects of trout on galaxiid growth and antipredator behaviour". Thesis, University of Canterbury. Biological Sciences, 2007. http://hdl.handle.net/10092/1438.

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The introduction of trout has been implicated in the declines in native fish fauna in New Zealand and worldwide. Since the introduction of brown (Salmo trutta) and rainbow (Oncorhynchus mykiss) trout to New Zealand in 1867, their distribution has spread and they have been implicated in the fragmentation of native fish distributions, particularly native non-migratory galaxiids. However, in the Upper Waimakariri basin the co-occurrence of trout and galaxiid populations is relatively common, even in streams where trout reach sizes known to be piscivorous. To investigate mechanisms that may regulate trout and galaxiid co-occurrence, I investigated differences in antipredator behaviour and growth rate between stream types with varying levels of trout presence. Using quantitative survey data collected between 1997 and 2006, I found that trout abundance was low and varied annually in frequently disturbed sites compared their high abundance in stable streams. This finding was used to classify streams into three population types, barrier (trout absent), disturbed (trout presence intermittent) and sympatric (constant trout presence). Using this classification, I tested the effects of trout chemical cues on galaxiid activity and refuge use in artificial channels. There were no differences in activity or refuge use between trout odour and there were no effects of population type or galaxiid size during both the day and the night. Using otolith weight-fish length relationships in galaxiids collected from each population type, I found that galaxiid growth rate was higher in disturbed streams than in stable streams either with or without trout. An experiment manipulating trout size and presence, over two months in a natural stream, found galaxiids from treatments without trout grew slower than those with trout. Slow growth rates in galaxiids above trout-migration barriers and in sympatry, combined with low growth rates in treatments without trout suggest that the mechanisms that regulate galaxiid growth are more complex than previously thought.

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Muñoz, Mas Rafael. "Multivariate approaches in species distribution modelling: Application to native fish species in Mediterranean Rivers". Doctoral thesis, Universitat Politècnica de València, 2018. http://hdl.handle.net/10251/76168.

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This dissertation focused in the comprehensive analysis of the capabilities of some non-tested types of Artificial Neural Networks, specifically: the Probabilistic Neural Networks (PNN) and the Multi-Layer Perceptron (MLP) Ensembles. The analysis of the capabilities of these techniques was performed using the native brown trout (Salmo trutta; Linnaeus, 1758), the bermejuela (Achondrostoma arcasii; Robalo, Almada, Levy & Doadrio, 2006) and the redfin barbel (Barbus haasi; Mertens, 1925) as target species. The analyses focused in the predictive capabilities, the interpretability of the models and the effect of the excess of zeros in the training datasets, which for presence-absence models is directly related to the concept of data prevalence (i.e. proportion of presence instances in the training dataset). Finally, the effect of the spatial scale (i.e. micro-scale or microhabitat scale and meso-scale) in the habitat suitability models and consequently in the e-flow assessment was studied in the last chapter.
Esta tesis se centra en el análisis comprensivo de las capacidades de algunos tipos de Red Neuronal Artificial aún no testados: las Redes Neuronales Probabilísticas (PNN) y los Conjuntos de Perceptrones Multicapa (MLP Ensembles). Los análisis sobre las capacidades de estas técnicas se desarrollaron utilizando la trucha común (Salmo trutta; Linnaeus, 1758), la bermejuela (Achondrostoma arcasii; Robalo, Almada, Levy & Doadrio, 2006) y el barbo colirrojo (Barbus haasi; Mertens, 1925) como especies nativas objetivo. Los análisis se centraron en la capacidad de predicción, la interpretabilidad de los modelos y el efecto del exceso de ceros en las bases de datos de entrenamiento, la así llamada prevalencia de los datos (i.e. la proporción de casos de presencia sobre el conjunto total). Finalmente, el efecto de la escala (micro-escala o escala de microhábitat y meso-escala) en los modelos de idoneidad del hábitat y consecuentemente en la evaluación de caudales ambientales se estudió en el último capítulo.
Aquesta tesis se centra en l'anàlisi comprensiu de les capacitats d'alguns tipus de Xarxa Neuronal Artificial que encara no han estat testats: les Xarxes Neuronal Probabilístiques (PNN) i els Conjunts de Perceptrons Multicapa (MLP Ensembles). Les anàlisis sobre les capacitats d'aquestes tècniques es varen desenvolupar emprant la truita comuna (Salmo trutta; Linnaeus, 1758), la madrilla roja (Achondrostoma arcasii; Robalo, Almada, Levy & Doadrio, 2006) i el barb cua-roig (Barbus haasi; Mertens, 1925) com a especies objecte d'estudi. Les anàlisi se centraren en la capacitat predictiva, interpretabilitat dels models i en l'efecte de l'excés de zeros a la base de dades d'entrenament, l'anomenada prevalença de les dades (i.e. la proporció de casos de presència sobre el conjunt total). Finalment, l'efecte de la escala (micro-escala o microhàbitat i meso-escala) en els models d'idoneïtat de l'hàbitat i conseqüentment en l'avaluació de cabals ambientals es va estudiar a l'últim capítol.
Muñoz Mas, R. (2016). Multivariate approaches in species distribution modelling: Application to native fish species in Mediterranean Rivers [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/76168
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Perkin, Joshuah Shantee. "Fragmentation in stream networks: quantification, consequences, and implications to decline of native fish fauna". Diss., Kansas State University, 2012. http://hdl.handle.net/2097/14954.

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Doctor of Philosophy
Department of Biology
Keith B. Gido
Habitat fragmentation and loss threaten global biodiversity, but organism responses to changing habitat availability are mediated by structural properties of their habitats. In particular, organisms inhabiting dendritic landscapes with hierarchically arranged branches of habitat tend to have limited access to some patches even in the absence of fragmentation. Consequently, organisms inhabiting dendritic landscapes such as streams respond strongly to fragmentation. Using a combination of meta-analysis, field observations, and ecological network modeling I show that stream fishes respond to fragmentation in predictable ways. First, I addressed how dams and stream dewatering have created a mosaic of large river fragments throughout the Great Plains. Using a geographic information system and literature accounts of population status (i.e., stable, declining, extirpated) for eight “pelagic-spawning” fishes, I found stream fragment length predicted population status (ANOVA, F2,21 = 30.14, P < 0.01) and explained 71% of reported extirpations. In a second study, I applied a new measure of habitat connectivity (the Dendritic Connectivity Index; DCI) to 12 stream networks in Kansas to test the DCI as a predictor of fish response to fragmentation by road crossings. Results indicated fish communities in stream segments isolated by road crossings had reduced species richness (alpha diversity) and greater dissimilarity (beta diversity) to segments that maintained connectivity with the network, and the DCI predicted patterns in community similarity among networks (n = 12; F1,10 = 19.05, r2 = 0.66, P < 0.01). Finally, I modeled fish distributions in theoretical riverscapes to test for mechanistic linkages between fragmentation and local extirpations. Results suggested the number of small fragments predicted declines in patch occupancy, and the magnitude of change in occupancy varied with dispersal ability (“high” dispersers responded more strongly than “low” dispersers). Taken together, these works show context-dependencies in fish responses to fragmentation, but a unifying theme is that small fragments contribute to attenuated biodiversity. Moreover, the predictable manner in which stream fish react to fragmentation will aid in biodiversity conservation by revealing potential responses to future scenarios regarding changes to habitat connectivity.

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Sweet, Diana E. "Movement patterns and habitat associations of native and introduced catostomids in a tributary system of the Colorado River". Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1445041561&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.

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Sleezer, Logan John. "Abundance Trends and Drivers of Change in Freshwater Fish Communities of the New River Basin". Thesis, Virginia Tech, 2020. http://hdl.handle.net/10919/99149.

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Habitat destruction/alteration and non-native species are widely considered the two most serious threats to biodiversity within freshwater ecosystems, which are among the most threatened in the world. I examined the effects of these factors, specifically focusing on land use and non-native species as drivers of abundance patterns of native fishes in the highly invaded and anthropogenically impacted New River basin (NRB) in the Appalachian region of the United States. In chapter 2, I examine current native and non-native species abundance patterns related to the highly variable land-use mosaic present across the NRB, with specific focus on the species-specific effects of intensive land-use practices (agriculture and urbanization) at varying spatial extents (upstream watershed, upstream riparian, and local riparian). In chapter 3, I investigate historical context of basin-wide and site-level abundance spread and decline of natives and non-natives in the upper and middle New River basin (UMNR) over the past 60+ years. Finally, in chapter 4, I partition the variation in native species abundance explained separately by land use and non-native species to determine which factor might be most influential in describing abundance distributions of UMNR native fishes over the past 20+ years. My results indicate widely varying responses of native species to various combinations of intensive land use and non-native species across contributing watersheds and widespread biotic homogenization and native species declines over the past 60+ years. These declines include reductions in unique communities and endemic species provided little consideration or protection under current conservation law. I suggest potential avenues for improvement of conservation actions to help preserve these unique species and communities based on their responses to various land-use and non-native species stressors. My study framework should be broadly applicable to other drainages and should provide opportunities for early identification of potential native species declines and the stressors that may be contributing to them.
Master of Science
Freshwater fishes are experiencing world-wide declines that have the potential to cause major negative ecological and economic impacts. Two of the biggest contributors to fish declines are habitat destruction and non-native species introductions. I examined populations of numerous fish species in the New River basin (NRB) in the Appalachian region of the United States to identify declining native species and determine how intensive land use (one type of habitat destruction) and non-native species may be contributing to these trends. My results suggest that nearly half of the native species occurring in the NRB may be experiencing widespread reductions in abundance. As a result of these declines and the spread of a few common native and non-native species, fish communities across the NRB are becoming less unique over time. Land-use changes, such as agricultural and road development near streams, which contribute to increased soil erosion and run-off of silt and sand into streams, could be causing broad habitat changes that lead to diminished populations of sensitive species and overall local and regional fish diversity. While no single non-native species may be held responsible for all native fish species declines in the NRB, complex interactions, such as competition and predation, between many natives and non-natives altogether could be contributing to many native fish declines. Farmers and other landowners can help to prevent future fish declines by re-establishing natural vegetation, such as trees, along streambanks and implementing other practices, such as cattle fencing, that reduce the streambank and soil erosion that harms fish habitat. Other stakeholders, such as anglers, can help prevent future native fish declines by limiting introductions of additional non-native species. For example, these stakeholders could avoid releasing aquatic pets and live bait into NRB streams. These practices would help limit future negative impacts caused by non-native species.

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Hitchman, Sean M. "A mosaic approach can advance the understanding and conservation of native biodiversity in natural and fragmented riverscapes". Diss., Kansas State University, 2017. http://hdl.handle.net/2097/38559.

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Doctor of Philosophy
Division of Biology
Martha E. Mather
Understanding the complex relationship between organismal distribution and spatial heterogeneity is central to many ecological questions. This challenge of identifying the biodiversity consequences of spatial patterns is especially critical for resource conservation at the larger riverscape scale because climate- and human-related impacts often act through intricate and spatially-connected organismal-habitat relationships. Specifically, resource managers cannot manage the adverse effects of common disturbances on aquatic ecosystems (e.g. water-withdrawal, dams, urbanization) if the influence of spatial heterogeneity is not recognized and understood. Towards this larger goal, I examined the role of spatial heterogeneity on stream fish biodiversity in the Upper Neosho River, KS in three ways. First, I used a mosaic approach (in which connected, interacting collections of juxtaposed habitat patches were examined) to build the scientific foundation for a general model that aids in the understanding and environmental management of disturbance-related, ecologically-based conservation problems. Second, I examined landscape metrics to quantify the impact of low-head dams on stream habitat and fish diversity. Third, I evaluated multiple quantitative approaches to develop a fuller understanding of how the arrangement of habitats across the riverscape influenced stream fish biodiversity. Related to these questions, the dissertation research provided four key take-home messages that advanced science-based conservation related to stream fish habitat and biodiversity. First, mapping larger-scale patterns of heterogeneity showed that quantitatively-different, physically-distinct pool, riffle, run, and glide habitats were arranged in unique combinations created diverse habitat mosaics across sites. Second, riffles, which comprised < 5% of all habitat patches, acted as keystone habitats that disproportionately increased fish biodiversity (i.e., species richness was significantly higher in mosaics with higher numbers of riffles). Third, mosaic approach metrics provided new insights into the influence of low-head dams on stream fish biodiversity that were not detected with traditional approaches to habitat sampling and statistical analysis. For example, low-head dams dampened the natural habitat diversity that is needed for the maintenance of resilient communities. Furthermore, using path analysis, I found that species richness was higher immediately below low-head dams as mediated through an increase in the proportion of riffle habitat, but this higher species richness was offset by a greater decrease in species richness in the impoundment habitat above low-head dams. Thus, the choice of scale influenced the interpretation of how dams affected habitat heterogeneity and resultant organismal patterns. Finally, landscape approaches to examining compositional and configurational heterogeneity provided new insights about stream fish habitat-biodiversity relationships. For example, riffle patch density had a positive effect on species richness, species richness was higher within shallow, slow flowing riffles, and adjacent neighbor habitats affected riffle species richness as mediated through alterations to within-habitat characteristics. In summary, quantifying the complex patterns of spatial heterogeneity in a range of ways can aid in the understanding of habitat-biodiversity patterns and help conserve stream fishes at a variety of scales.

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Dolan, Jamie Marie. "'Do Good Things for the Fish': Organizational Innovation in Tribal Governance". Diss., The University of Arizona, 2009. http://hdl.handle.net/10150/195674.

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This dissertation examines the organizational aspects of fish and wildlife management for Native American nations. Fish and wildlife management is an arena of great importance to many Native nations in subsistence, economic and cultural realms. Additionally, fish and wildlife, being common-pool resources, offer interesting management challenges. My research focuses on what happens when Native American nations exercise self-determination in this arena which requires them for both political and practical reasons to interact with state and federal governments and for economic reasons to deal with markets, all while attempting to meet the needs of their nations. Using fuzzy-set qualitative comparative analysis and drawing upon survey and case study research with Native American fish and wildlife programs, I examine how tribes manage their fish and wildlife resources and with what results.This research helps identify under what conditions tribes may achieve various management goals. In some important ways, tribes are limited in what they can do, particularly in regards to land base size and degree of jurisdiction over non-Indians. More importantly, however, this research identifies some of the many ways tribes can work to take charge of or support tribal fish and wildlife management without having to appeal to outsiders. While there are some very real limitations to fish and wildlife management external to tribes, within those limits, tribes have opportunities to assume and be effective in resource management.This dissertation also provides evidence to suggest that as tribes are better able to determine their own management and governance paths, elements of clan structures and logics develop where the organizational literature would predict they would not. Studying tribal fish and wildlife programs in particular offers an examination of these clan-like features typically found only on the societal fringes. Perhaps even more importantly, this dissertation research demonstrates that there are different governance structures, or logics, co-existing and operating in hybrid forms. For tribes, these hybrid structures create some challenges and inconsistencies that more pure governance structures would not. Nevertheless, these hybrid structures also allow for flexibility and effectiveness in responding to the diverse stakeholders invested in or influencing tribal fish and wildlife management.

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my, marina@umt edu, i Marina Hassan. "Parasites of native and exotic freshwater fishes in the south-west of Western Australia". Murdoch University, 2008. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20090720.141418.

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Fewer than 200 fish species are found in freshwater habitats in Australia, of which 144 are confined exclusively to freshwater. At least 22 species of exotic freshwater fish have been introduced into Australia, and 19 of these have established self-sustaining populations. However, the parasite fauna of both native and exotic freshwater fishes in Australia is poorly known. This is particularly the case in the south-west of Western Australia, where there have been no previous comprehensive studies of the parasites of 14 native species and nine or more exotic species of fish found in freshwater habitats. This study represents a survey of the parasites of freshwater fishes in the South West Coast Drainage Division and reports 44 putative species of parasites in 1429 individual fishes of 18 different species (12 native and six exotic) from 29 locations. Parasites were found in 327 (22.88%) fishes, and of the infected fishes, 200 (61.16%) were infected with only one species of parasite and 127 (38.84%) were infected with two or more species of parasites. For helminth and arthropod parasites, which were more comprehensively surveyed than protozoan and myxozoans, I found 37 species compared to 77 species found in a recent study of fishes from the East Coast Drainage Division. The present study demonstrated that parasitic infection was significantly more common in native fish species (mean prevalence of infection with any species of parasite = 0.36 ± 0.09) than in exotic fish species (0.01 ± 0.12). Parasites were found in all native fish species, but in only two exotic fish species that were examined. Parasite regional and component community diversity were estimated by species richness (the number of species, S) and by an index of taxonomic diversity (HT). Both parasite species richness and parasite taxonomic diversity were significantly greater in native fish species (mean S = 10.5 ± 2.3; mean HT = 1.19 ± 0.14) than in exotic fish species (mean S = 1.6 ± 3.3; mean HT = 0.27 ± 0.20). These relationships were consistent over all geographic locations that were sampled. The reduced parasite load of exotic species compared to native species has been previous reported across a wide range of taxa. It is thought to arise partly because founding populations of hosts have a low probability of harbouring the species total parasite fauna, and partly because parasites that infect introduced exotic species may not be able to maintain their life cycle in the new environment. It has been suggested that a reduced parasite load increases the competitive ability of exotic species compared to native species (the parasite release hypothesis) and this may partly explain the abundance and apparent competitive success of exotic over native species of freshwater fish in the South West Coast Drainage Division. For native species of fish, there were major differences among species in both prevalence of parasitic infection and parasite community diversity, but this variation was not related to fish size, whether the fish were primarily freshwater or primarily estuarine, or whether they were primarily demersal or pelagic. In this study, I report two new parasites in south western Australian waters. Both are copepod parasites; Lernaea cyprinacea and a new species of Dermoergasilus. The Dermoergasilus appears to be native to the south-west of Western Australia and has been described as Dermoergasilus westernensis. It differs from previously described species in the genus principally by the armature of the legs. This new species was found on the gills of freshwater cobbler, Tandanus bostocki and western minnow, Galaxias occidentalis in two different river systems. Lernaea cyprinacea is an introduced parasitic copepod found on the skin and gills of freshwater fishes in many areas of the world. The parasite has not previously been reported in Western Australia. We found infestations of L. cyprinacea on four native fish species (G. occidentalis; Edelia vittata; Bostockia porosa; T. bostocki) and three introduced fish species (Carassius auratus; Gambusia holbrooki; Phalloceros caudimaculatus) at two localities in the Canning River, in the south-west of Western Australia. The parasite has the potential to have serious pathogenic effects on native fish species, although it appears to be currently localised to a small section of the Canning River. Over all localities from which fishes were sampled in the present study, the proportion of native freshwater fishes with parasitic infections and the component community diversity of the parasite fauna of native fishes were both negatively related to habitat disturbance, in particular to a suite of factors (river regulation, loss of riparian vegetation, eutrophication and presence of exotic fish species) that indicate increased human usage of the river and surrounding environment. The reduced parasite load and diversity in native fishes from south-west rivers with greater human usage was due principally to the loss of a number of species of trematode, cestode and nematode endoparasites which use fishes as intermediate hosts. Other studies have also found that endoparasites with complex life cycles are most likely to be adversely affected by environmental changes, presumably because any environmental changes which impact on either free-living parasite stages or on any of the hosts in the complex train of parasite transmission will reduce parasite population size and may cause local extinction of the parasite species. The most heavily infected species of native freshwater fish in the South West Coast Drainage Division was T. bostocki with 96% of all individuals containing at least one species of parasite. As with most freshwater fishes of south-west Australia, T. bostocki is limited in its distribution to waterways with relatively low salinity. The degree of parasitism and histopathology of internal and external organs in T. bostocki from the Blackwood River was examined over a period of rapid, seasonal changes in water salinity. As salinity increased, the infracommunity richness and prevalence of ectoparasites on the skin of fishes decreased, while the infracommunity richness and prevalence of endoparasites increased. This was associated with a decrease in histopathological lesion scores in the skin and an increase in histopathological lesion scores in internal organs, particularly the intestine. I hypothesise that the seasonal spike in salinity had two contrasting effects on parasitic infections of T. bostocki. Firstly, it increased the mortality rate of parasites directly exposed to water, leading to a decrease in ectoparasitic infection and associated pathology. Secondly, it suppressed immune function in fish, leading to a decreased mortality rate of parasites not directly exposed to water and a more severe pathological response to endoparasitism.

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Hurst, Timothy Parker. "Evaluation of Australian native fish and lavicides for the integrated control of freshwater mosquito vectors /". [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18164.pdf.

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Alcaraz, Cazorla Carles. "Ecological interactions between an invasive fish (Gambusia holbrooki) and native cyprinodonts: the role of salinity". Doctoral thesis, Universitat de Girona, 2006. http://hdl.handle.net/10803/7868.

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Actualment una de les principals amenaces a la biodiversitat és la introducció d'espècies. Revisant 26 variables de les 69 espècies de peixos continental de la Península Ibèrica concloem que la filogènia, variabilitat i els usos de l'home són necessaris per entendre millor les diferències entres les espècies natives i invasores.
Entre les especies més afectades per la introducció de peixos es troben els ciprinodontiformes endèmics del Mediterrani. Aportem les primers dades sobre l'ús d'hàbitats ocasionalment inundats i la selecció de preses del fartet (Aphanius iberus), observant un canvi ontogenètic, clarament relacionat amb el microhàbitat.
També demostrem que la salinitat influeix en l'èxit invasor de la gamúsia, afectant la seva densitat i biologia reproductiva. Per altra banda, demostrem experimentalment que amb l'increment de salinitat la gambúsia disminueix la seva agressivitat i captura menys preses, reduint la seva eficàcia competitiva respecte dels ciprinodonts natius.
One of the main current threats to biodiversity is the introduction of invasive species. By reviewing 26 life-history and ecological variables of the 69 inland fish species of the Iberian Peninsula we conclude that phylogeny, variability and human use are needed to a better understanding of the differences between native and invasive species.
Among the most threatened species by invasive fish are the Mediterranean endemic cyprinodontiform fish. We report the first data on the use of occasionally-inundated habitats ad prey electivity by the Spanish toothcarp (Aphanius iberus). We observed an ontogenetic diet shift clearly linked to a microhabitat change.
We also demonstrate that salinity limits the invasive success of mosquitofish (Gambusia holbrooki), affecting density and life history traits. ON the ohter hand, we experimentally demonstrate that mosquitofish decreases its aggresive behavior and capture less prey, reducing its competitive efficiency with salinity increases regarding to native ciprinodonts.

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Kim, Gene Wook. "Trophic transfer of energy and polychlorinated biphenyls by native and exotic fish in Lake Erie". Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1174664048.

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Kim, Gene W. "Trophic transfer of energy and polychlorinated biphenyls by native and exotic fish in Lake Erie". The Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=osu1174664048.

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Trujillo, Vanessa. "Jewels for Dollars: Native and Nonnative Freshwater Fish Interactions in a Stressful Dry Down Environment". FIU Digital Commons, 2017. http://digitalcommons.fiu.edu/etd/3212.

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Vertebrate populations are subjected to novel anthropogenic stressors that are expected to multiply exponentially in the future. Introductions of nonnative species and human-altered hydrology are among these stressors to native species communities. The Rocky Glades, located in Everglades National Park, may serve as a population sink for native species that typically do not survive the altered hydrology of the dry season, and as a source of nonnative species that may be better adapted to chronically stressful conditions. In the seasonally-flooded Everglades, the nonnative African Jewelfish invaded in the 1960s and has since shown rapid range expansion. African Jewelfish are aggressive and territorial, thus they are predicted to be more successful at acquiring space and resources, and may displace native Sunfishes. I monitored assemblages of fish across time in experimental mesocosms and solution holes and quantified survivorship and body condition of both natives and nonnatives. Overall, native Sunfish did poorly while nonnatives had higher survivorship over the course of the dry season. Unexpectedly, no evidence indicated that Jewelfish reduced survival of native Sunfish. I compared aggressive interactions between native Dollar Sunfish and nonnative African Jewelfish in Sunfish populations either sympatric or allopatric with Jewelfish. Sympatric Dollar Sunfish were twice as likely to approach African Jewelfish as allopatric ones. My study suggests native species can survive invasion through behavioral adaptation to nonnative competitors. Characterizing interactions between native and nonnative species and identifying their niche use can assist in understanding the challenges of native species conservation in the face of species invasions.

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Reizenberg, Jody-Lee. "The thermal tolerances and preferences of native fishes in the Cape Floristic Region: towards understanding the effect of climate change on native fish species". Master's thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/25537.

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Global climate change models indicate that a rise in temperature and reduction in rainfall in the Western Cape Province of South Africa is inevitable and unavoidable. Within the Western Cape lies the Cape Floristic Region (CFR); a biodiversity hotspot with high levels of endemism. This includes its freshwater fish assemblage. Whereas the current greatest threats to native fish biodiversity are habitat degradation and invasion by non-native species, predicted climate change is likely to further impact fish communities negatively. As a master abiotic variable in aquatic ecosystems; temperature influences the fitness, behaviour, and life-histories of aquatic biota. Thermal alteration may therefore affect sensitive fish species. The upper thermal limit, determined via the critical thermal method, has been validated as a measure of thermal sensitivity. To better understand the impacts of climate change on the native fish of the CFR, upper thermal limits (critical thermal maxima/CTmax) were determined for seven native species of freshwater fish. Thermal preferences were also determined for five of these species using the acute gradient tank approach to elucidate thermal habitat preferences. Species that were identified by the IUCN as vulnerable, endangered, or critically endangered were selected from the four main families of native fish in the CFR (Anabantidae, Austroglanidae, Cyprinidae, and Galaxiidae), from four Rivers. Overall, Cape galaxias (Galaxias zebratus), Breede River redfin (Pseudobarbus burchelli), Berg River redfin (Pseudobarbus burgi), Clanwilliam redfin (Pseudobarbus calidus), and fiery redfin (Pseudobarbus phlegethon) were found to be most sensitive to increased temperature (CTmax= 29.8-32.7⁰C). Clanwilliam rock-catfish (Austroglanis gilli) and Cape kurper (Sandelia capensis) were found to be moderately sensitive (CTmax= 33.0-35.3⁰C). Similar trends were found using the thermal preference approach as CTmax and thermal preference were found to correlate well. The results were related to in-situ water temperature, which influenced both parameters. Thermal tolerances and preferences of all the native species exceed that of invasive salmonids (Onchorynchus mykiss and Salmo trutta). However, non-native centrarchids (Micropterus spp.) are more thermally tolerant, indicating an increase in threat by warm adapted non-natives. These data suggest that species interactions and distributions are likely to undergo substantial changes in response to elevated water temperature.

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Neves, Milene. "Exigência de proteína digestível, para alevinos de pacu (Piaractus mesopotamicus) alimentados com rações a base de farelo de soja e milho". Universidade Estadual do Oeste do Paraná, 2013. http://tede.unioeste.br:8080/tede/handle/tede/1545.

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Made available in DSpace on 2017-07-10T17:47:57Z (GMT). No. of bitstreams: 1 Milene_Neves.pdf: 839197 bytes, checksum: 4a4ebea4e484161475bd823485afd409 (MD5) Previous issue date: 2013-10-30
The objective of this study was to. Four diets with increasing levels of digestible protein (18, 22, 26 and 30 %) based on products of plant origin were evaluated. The fry were housed in 50L hapas which were inside 1000L tanks in the greenhouse. The temperature and, dissolved oxygen were daily verified and pH was weekly verified. The fry were fed three times a day (7:30a.m., 12: 30p.m. and 5:30p.m ) after the last feeding and removal of food debris feces was performed with subsequent replacement of the water system , and after weighing the pots ration to measure consumption . The experimental design was randomized blocks with six tanks 1000L (repetitions) with four 50L hapas tanks within these treatments (18, 22, 26 and 30% of digestible protein). Each hapa settled 10 fingerlings. The fry pacu that were previously weighed batch of water 10 (9.49g ± 0.04g average weight per fish), the overall length of 8.025cm, 6.28cm gage length, height and width of 3.005 cm and 0.56 cm. The measurements were obtained by averaging done after the initial biometrics. At the end of the experiment, a quadratic effect (p<0.01) for the average final weight, standard length, total length, height and width was observed. For vestments of zootechnical performance the feed conversion ratio and survival were evaluated, and for these parameters were those who had the significance of apparent feed conversion showed a quadratic effect (p<0.05). After expiration of the trial period the fry were slaughtered and their carcasses submitted to laboratory analyzes which were: crude protein, ether extract, moisture and ash. After that the results were submitted to the same simple linear regression, the mean linearly for fat and moisture. After all the analysis it was concluded that there is a point of maximum absorption of digestible protein to a higher average final weight which is 24.65%, and that the level of digestible protein obtained results for most parameters evaluated was 26% of digestible protein
O objetivo deste trabalho foi determinar a exigência de proteína digestível para alevinos de pacu (Piaractus mesopotamicus). Foram avaliadas quatro rações com níveis crescentes de proteína digestível (18, 22, 26 e 30%), à base de produtos de origem vegetal. Os alevinos foram alojados em hapas de 50L, que estavam dentro de tanques de 1000L, em estufa. Diariamente, verificou-se a temperatura e o oxigênio dissolvido e, semanalmente, e o pH. Os alevinos foram alimentados três vezes ao dia (7h:30, 12h:30 e 17h:30), e ao final da última alimentação foi realizada retirada de fezes e restos de alimentos, com posterior reposição da água do sistema, e posterior pesagem dos potes de ração para aferir o consumo. O delineamento experimental foi de blocos ao acaso, com seis tanques de 1000L (repetições), com quatro hapas de 50L dentro destes tanques com tratamentos (18, 22, 26 e 30% de proteína digestível). Cada hapa acomodou 10 alevinos. Os alevinos de pacu foram previamente pesados em lotes de 10 na água (9,49g ± 0,04 g de peso médio por peixe) apresentando comprimento total de 8,025cm, comprimento padrão de 6,28c, altura de 3,005cm e largura de 0,56cm. As medidas foram obtidas por intermédio de uma média feita após a biometria inicial. Ao final do experimento, foi observado um efeito quadrático (p<0,01) para o peso final médio, comprimento padrão, comprimento total, altura e largura. Para os parâmetros de desempenho zootécnico avaliou-se a conversão alimentar aparente e sobrevivência, sendo que para estes parâmetros o que teve significância foram o de conversão alimentar aparente, que apresentou efeito quadrático (p<0,05). Após o término do período experimental, os alevinos foram abatidos e suas carcaças submetidas às análises laboratoriais, tais como: proteína bruta, extrato etéreo, umidade e cinzas. Após a obtenção dos resultados, os mesmos foram submetidos à regressão linear simples, sendo significativo linearmente para extrato etéreo e umidade. Após todas as análises, concluiu-se que há um ponto máximo de absorção de proteína digestível para um maior peso final médio, que é de 24,65%, e que o nível de proteína digestível que mais obteve resultado para os parâmetros avaliados foi de 26% de proteína digestível

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38

Leyse, Karen Elizabeth. "Intentional introductions and biodiversity in fishless waters : the effects of introduced fish on native aquatic species /". For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2005. http://uclibs.org/PID/11984.

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39

Brown, Peter James. "Environmental conditions affecting the efficiency and efficacy of piscicides for use in non-native fish eradication". Thesis, Montana State University, 2010. http://etd.lib.montana.edu/etd/2010/brown/BrownP0510.pdf.

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Conservation of native fish is a pressing issue for fisheries managers. Conservation efforts often require eliminating threats posed by nonnative fish by eradicating them with piscicides. The piscicides rotenone and antimycin are used for eradication but their application is often inefficient or ineffective. My goal was to increase the efficiency and efficacy of nonnative fish eradication using piscicides. I identified environmental conditions affecting piscicide application, researched methods to overcome these problems, and provided tools that piscicide applicators can use to make piscicide application more efficient and effective. Rotenone and antimycin were exposed to varying levels of sunlight, turbulence, and dissolved organic matter (DOM) to determine the effect these environmental conditions have on piscicides. Bioassay fish were used to determine the toxicity of the piscicides. Sunlight and turbulence affected rotenone and antimycin but DOM did not. Increasing the concentration of chemical can increase the resistance to the effects of these environmental conditions; however, the effects of these conditions are considerable in natural settings. Observations of bioassay fish in stream applications of rotenone were used to develop a statistical model to predict the persistence of the piscicide. The model can be used to predict rotenone persistence in small montane streams and to estimate where rotenone concentrations need to be fortified. I measured the mixing rate of a chemical plume in different channel morphologies and at center or edge applications. Center application had a significantly shorter mixing distance than edge application, but mixing distance was not different among meandering, straight, and riffle/pool morphologies. Application of my findings will increase the efficiency and efficacy of native fish conservation using piscicides.

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40

Wilhite, Jerry W. "Use of infrared aerial photographs to identify and assess habitat needed by native fish in rivers". Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1445041571&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.

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41

Kinghorn, James Wolmarans. "The value of non-native fish species : a study of recreational angling in the Amathole district". Thesis, Rhodes University, 2013. http://hdl.handle.net/10962/d1001456.

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Experience has shown that effective fisheries governance requires a sound understanding of fisheries as systems incorporating both ecological and human dimensions. The Ecosystem Approach to Fisheries requires that the human components of these systems be considered when developing management and governance frameworks. While the potential for inland fisheries to contribute towards societal welfare and the development of rural livelihoods is becoming increasingly apparent, developing South African inland fisheries requires a careful consideration of both their positive and negative impacts, given that they revolve mainly around five of the world‟s top 100 invasive species. This thesis aimed to explore the value of inland recreational fisheries to rural livelihoods in the Amathole District of South Africa, to the regional economy, and to anglers themselves. Three methods were used to isolate this value. Economic impact analysis was used to estimate the combined total economic impact of the 2011 Divisional Tournament (n=31) and the 2012 Amatola Bass Classic (n=100) on the regional economy of the Amathole District, estimated to be R106 625. The travel cost method was applied to data from the 2012 Amatola Bass Classic in order to estimate the social welfare generated by this tournament. The Negative Binomial model, corrected for truncation and endogenous stratification, estimated this value at R 1 960 090. The sustainable livelihoods framework was used to conduct a broad-based analysis of the value of Amatola Wild Trout, the firm which constitutes the fishery surrounding the rural village of Cata. It was found that the fishery had been responsible for a modest pecuniary impact on the community of Cata within its first two years of establishment, although significant improvements in human capital were found to have resulted from the development of the fishery. These results provide insights into the economic dimension of fisheries in the Amathole District, and will prove useful when weighing up the positive and negative impacts of non-native fish species, particularly when informing decisions regarding their potential eradication.

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42

Pitts, Kristen Leah. "Assessing threats to native fishes of the Lower Colorado River Basin". Thesis, Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/869.

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43

Henkanaththegedara, Sujan Maduranga. "Ecological Complexity of Non-Native Species Impacts in Desert Aquatic Systems". Diss., North Dakota State University, 2012. https://hdl.handle.net/10365/26697.

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Without an adequate understanding of complex interactions between native and non-native species, management of invasive species can result in unforeseen detrimental impacts. I used both field and laboratory experiments to study reciprocal species interactions between the endangered Mohave tui chub (Siphateles bicolor mohavensis) and invasive western mosquitofish (Gambusia affinis). I also examined the impacts of both fish species on the aquatic invertebrate communities in desert springs. I demonstrate a case of intraguild predation (IGP) as a mechanism facilitating co-persistence of the endangered Mohave tui chub with invasive mosquitofish using field mesocosm experiments. In this case of IGP, adult tui chub prey on adult and juvenile mosquitofish, while adult mosquitofish prey on tui chub eggs and/or larvae. I conducted laboratory predation trials to assess if IGP was size-structured due to predator gape-limitation. I explored sex specific differences in gape-size limitation in mosquitofish, because mosquitofish are sexually dimorphic. Larval tui chubs had lower survival in the presence of female mosquitofish than in the presence of males. Reciprocally, male mosquitofish had lower survival than the females in the presence of Mohave tui chub. These results combined with vulnerability modeling supported that IGP in this system is size structured based on gape-size limitation. These results collectively suggest size-structured IGP may facilitate the co-persistence of these two fish species. My findings also suggest that mosquitofish may not be a limiting factor for the persistence of the endangered Mohave tui chub. Further, habitats currently harboring mosquitofish were considered as future refuge habitats for Mohave tui chub, a management option previously un-available. In addition to such reciprocal interactions between fish species, recently established fish populations may impact unique invertebrate communities. Mesocosm experiments with sympatric and allopatric populations of tui chub and mosquitofish showed negative impacts of both fish species on changes of invertebrate community structure. Specifically, fish caused population declines and, in some cases, extirpations of various invertebrate taxa. These results suggest important conservation implications of invasive fish as well as protected fish transplants into fishless desert springs. Overall my research emphasizes the complexity of ecological interactions between native and non-native fish species in desert aquatic systems.

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44

Schilling, Emily Gaenzle. "Effects of Fish Introductions on the Geographic Distribution and Native Invertebrate Biodiversity of Naturally Fishless Lakes in Maine". Fogler Library, University of Maine, 2008. http://www.library.umaine.edu/theses/pdf/SchillingEG2008.pdf.

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45

Sestrich, Clint Michael. "Changes in native and nonnative fish assemblages and habitat following wildfire in the Bitterroot River Basin, Montana". Thesis, Montana State University, 2005. http://etd.lib.montana.edu/etd/2005/sestrich/SestrichC1205.pdf.

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Wildfire frequency and severity have increased over the past decade but few studies have assessed the effects of large, intense fires on native salmonids in the Intermountain West. I utilized a unique data set with 1-11 years of pre-fire population data in 24 small streams in the Bitterroot River basin in western Montana to determine if habitat changes caused by a large (1,108 kmÂ²) wildfire and associated debris flows favored nonnative brook trout Salvelinus fontinalis over native westslope cutthroat trout Oncorhynchus clarkii lewisii and bull trout S. confluentus. I used before-after control-impact (BACI) and extensive post-treatment study designs to determine whether changes in species abundance and habitat increased with increasing burn severity and debris flows. Species abundance was estimated pre- and post-fire with mark-recapture electrofishing and habitat conditions post-fire were assessed by measuring substrate, temperature, large woody debris, and habitat type. Stream temperature and sedimentation generally increased with burn severity whereas habitat complexity decreased with increasing burn severity and presence of debris flows. However, recovery of native trout populations was rapid with populations approaching or surpassing predisturbance levels within three years. In contrast, brook trout recovery was less apparent especially in debris flow reaches as the proportion of brook trout to the total salmonid assemblage decreased each year post-fire. However, one notable exception occurred in a high burn severity reach on Rye Creek, where brook trout increased by 499% and apparently replaced bull trout. Model results indicated that brook trout abundance was negatively related to stream gradient, elevation, and the proportion of a basin that was burned and positively related to watershed area, water temperature, and pool frequency. Spread of nonnative species to reaches where undetected pre-fire (n = 7) occurred irrespective of wildfire disturbance with brown trout Salmo trutta being the primary invading species (n = 5) and only one occurrence of brook trout and rainbow trout Oncorhynchus mykiss invasion. Although changes in aquatic habitat following wildfire have the potential to favor nonnative fishes, connected cutthroat trout and bull trout populations in the Bitterroot River basin were resilient to disturbance and generally recovered more rapidly than nonnative brook trout.

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46

Evans, Jr Hudman. "Comparison of Resource Use by Invasive Black Carp and Native Fish Using Isotopic Niche and Diet Analyses". OpenSIUC, 2020. https://opensiuc.lib.siu.edu/theses/2727.

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Black Carp (Mylopharyngodon piceus) is an invasive fish species native to Asia that has become increasingly abundant within the Mississippi River Basin during the past decade. Originally introduced to control snails that are an intermediate host for trematode parasites of fishes in aquaculture ponds, Black Carp are now present in several rivers in the U.S. and represent a potential threat to threatened and endangered mussel populations. Black Carp have historically been classified as molluscivores; however, a recent study that examined gut contents of Black Carp collected from the Mississippi River Basin indicated that Black Carp are opportunistic consumers that prey upon a wide variety of invertebrates and are flexible in their feeding modes. Despite the potential for Black Carp to compete with native riverine fish species for invertebrate prey, only one published study has compared Black Carp trophic position with that of native fishes in a small portion of the Black Carp’s invaded range. Therefore, the objectives of this study were to assess trophic overlap between Black Carp and two fish species native to the Mississippi River Basin using isotopic niche analysis and gut contents analysis. Dorsal muscle tissue samples were collected from Black Carp, Freshwater Drum (Aplodinotus grunniens), and Blue Catfish (Ictalurus furcatus) and analyzed for δ13C and δ15N to assess each species’ isotopic niche. Freshwater Drum and Blue Catfish gut contents were also removed and analyzed and compared to published Black Carp stomach contents data. Gut contents analysis indicated differences in diet composition between Black Carp and the two native fish species. Chironomidae had the highest frequency of occurrence (67%) and percent of taxa by number (47%) for Freshwater Drum. Trichoptera had the highest frequency of occurrence (58%) and percent of taxa by number (30%) for Blue Catfish, and Gastropoda had the highest frequency of occurrence (16.5%) of any specific prey taxa for Black Carp. Black Carp showed low isotopic niche overlap (≤47%) with both native species when muscle tissue δ13C and δ15N data from all fish collection locations were combined and when assessment of isotopic niches was restricted to the subset of locations where all three species were collected. Isotopic niche overlap was also low (10-48%) between Black Carp and both native species when isotopic niches were compared at individual collection locations. Intraspecific isotopic niche overlap among fish collection locations was highly variable (0-69%) within each of the three species, highlighting the need to assess interspecific isotopic niche overlap by collection location. Broad isotopic niches exhibited by Black Carp in the Mississippi River and tributaries are indicative of substantial trophic diversity among individuals and use of multiple basal energy sources, consistent with a recently published study which found that Black Carp diet composition differed among individuals and that Black Carp consumed a variety of invertebrates, including non-benthic taxa.

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47

Burbank, Nora K. "Have Introduced Brown Trout (Salmo Trutta) Affected Native Aquatic Vertebrates in Western United States Streams?" DigitalCommons@USU, 2011. https://digitalcommons.usu.edu/etd/1070.

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The introduction of exotic species is one of the greatest threats to freshwater biodiversity. Brown trout are native to Eurasia, but have been introduced to much of the rest of the world, including the United States. In other parts of their introduced range, brown trout have caused substantial negative effects to native species‟ abundances and distributions, and have altered the structure of some aquatic communities. In the United States, studies of some streams and watersheds have shown that brown trout can negatively affect native species, but I found no study that considers the effect of brown trout across a large portion of their introduced range. For this study, I examined if (1) the abundance and distribution of two ecologically different native fish taxa (sculpins and speckled dace) and (2) the structure of entire stream vertebrate assemblages were negatively associated with the presence and abundance of brown trout. I based my analyses on existing, standardized survey data collected across streams of the western United States. I found no relationship between brown trout and the abundance, presence-absence, or probability of detection of sculpins or speckled dace. I also found that brown trout were not associated with the structure of native stream vertebrate assemblages. My results imply that native stream vertebrates in western US streams are able to coexist with brown trout across the western United States, despite the negative effects brown trout can have on some taxa in individual watersheds or rivers.

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48

Pereira, Daiane Kelly Alves. "Tempo de digest?o e caracteriza??o do trato digest?rio de larvas de pacam? (Lophiosilurus alexandri)". UFVJM, 2016. http://acervo.ufvjm.edu.br/jspui/handle/1/1323.

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?rea de concentra??o: Aquicultura.
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Funda??o de Amparo ? Pesquisa do Estado de Minas Gerais (FAPEMIG)
Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)
Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq)
Banco do Nordeste do Brasil S.A. (BNB)
A aquicultura ? uma pr?tica brasileira que cresceu expressivamente nas ?ltimas d?cadas, contudo, a produ??o de pescados ainda ? insuficiente para atender a demanda interna. Na ?sia, maior produtor mundial de pescados, 95% das esp?cies produzidas s?o nativas, enquanto no Brasil, esse percentual est? abaixo de 20%. Este estudo teve como objetivo verificar o tempo de digest?o e avaliar o trato digest?rio de larvas de Lophiosilurus alexandri, uma esp?cie nativa do Rio S?o Francisco. As larvas foram avaliadas com 12 e 19 dias de vida, alimentadas com n?uplios de art?mia salina. Para avalia??o do tempo de digest?o nos diferentes dias de amostragem foi utilizada uma regress?o linear. Ao t?rmino do experimento foram aferidas as medidas de peso (g), e comprimento total (CT), comprimento de boca (CBO) e largura de boca (LBO) (mm). Para caracteriza??o do trato, al?m das j? citadas, foram tomadas medidas de comprimento total, comprimento boca/es?fago, comprimento do est?mago, comprimento do intestino, comprimento da boca, largura de boca e quociente intestinal para 12 e 19 dias de vida. As larvas apresentaram nos diferentes dias de amostragem peso, CT, CBO, LBO e QI de 41,18 mg e 76,88 mg, 17,78 mm e 20,98 mm, 0,42 mm e 0.73 mm, 2,71 mm e 3,57 mm, 0,29 mm e 0,32 mm aos 12 e 19 dias respectivamente. Foi verificado para os par?metros observados um maior desenvolvimento das larvas com 19 dias em rela??o as de 12 dias. Os par?metros de qualidade de ?gua mantiveram-se est?veis durante todo o per?odo experimental, permanecendo dentro dos valores aceit?veis para a larvicultura da esp?cie, assim como o crescimento em peso e comprimento. A avalia??o do desenvolvimento do sistema digest?rio das larvas foi realizada atrav?s de an?lises histol?gicas. O tempo de digest?o em larvas com 12 dias de vida foi menor (2 h 39 min 18 s) do que as de 19 dias (3 h 5 min 50 s). Por outro lado, larvas com 19 dias de vida apresentam trato digest?rio mais diferenciado em rela??o a 12 dias, permitindo assimilar melhor o alimento, aumentando assim a probabilidade de sobreviv?ncia dos indiv?duos.
Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Zootecnia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2016.
Aquaculture is a Brazilian practice that has grown significantly in the last decades, however, fish production is still insufficient to meet domestic demand. In Asia, the world's largest fish producer, 95% of the species produced are native, while in Brazil, this percentage is below 20%. This study aimed to verify the digestion time and to evaluate the digestive tract of larvae of Lophiosilurus alexandri, a species native to the S?o Francisco River. The larvae were evaluated at 12 and 19 days of age, fed with Artemia salina nauplii. To evaluate the digestion time on the different sampling days a linear regression was used. At the end of the experiment, the measurements of weight (g), total length (CT), length of mouth (BOD) and mouth width (LBO) (mm) were measured. For characterization of the tract, in addition to those already mentioned, measurements were taken of total length, mouth length / esophagus, length of the stomach, length of the intestine, length of mouth, mouth width and intestinal quotient for 12 and 19 days of life. The larvae presented, on the different days of sampling, weight, CT, CBO, LBO and IQ of 41.18 mg and 76.88 mg, 17.78 mm and 20.98 mm, 0.42 mm and 0.73 mm, 2.71 mm And 3.57 mm, 0.29 mm and 0.32 mm at 12 and 19 days respectively. It was verified for the observed parameters a greater development of the larvae with 19 days in relation to the 12 days. The water quality parameters remained stable throughout the experimental period, remaining within acceptable values for the species larviculture, as well as growth in weight and length. The evaluation of the development of the digestive system of the larvae was performed through histological analysis. The digestion time in larvae with 12 days of life was lower (2 h 39 min 18 s) than those of 19 days (3 h 5 min 50 s). On the other hand, larvae with 19 days of life present digestive tract more differentiated in relation to 12 days, allowing assimilating the food better, thus increasing the probability of survival of the individuals.

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49

Bahn, Leslie. "An assessment of losses of native fish to irrigation diversions on selected tributaries of the Bitterroot River, Montana". Thesis, Montana State University, 2007. http://etd.lib.montana.edu/etd/2007/bahn/BahnL1207.pdf.

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50

Oliveira, Kátia Rodrigues Batista de [UNESP]. "Grãos de milho de destilaria secos com solúveis em dietas para juvenis de Piaractus mesopotamicus (Holmberg 1987)". Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/143961.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Devido ao maior interesse por biocombustíveis, indústrias brasileiras iniciaram, recentemente, a produção de etanol também a partir de grãos de milho, gerando um resíduo com potencial de uso como ingrediente em rações para animais, o DDGS (grãos secos de destilaria com solúveis). Por resultar de processos de fermentação de grãos de milho por leveduras e enzimas, este resíduo possui um elevado teor proteico e baixo teor de carboidratos solúveis, o que o torna boa fonte de proteína vegetal em rações para animais. Além do baixo custo, possíveis benefícios relacionados aos resíduos de leveduras e enzimas restantes da fermentação também contribuem para seu potencial de mercado. Desta forma, com este trabalho, objetivou-se avaliar a viabilidade de inclusão do DDGS do milho em dietas para juvenis de Piaractus mesopotamicus em substituição ao farelo de soja. Para tal, foram realizados três ensaios experimentais. No primeiro ensaio avaliaram-se os coeficientes de digestibilidade aparente (CDA) de nutrientes do DDGS para juvenis de P. mesopotamicus (13±0.3 gramas), distribuídos, em delineamento inteiramente casualizado (DIC), em seis tanques de fibra de vidro, na densidade de 35 peixes tanque -1 em sistema de recirculação contínuo de água. A coleta das fezes foi realizada em sistema de Guelph modificado. Após obtenção dos CDAs, foram formuladas dietas contendo cinco diferentes níveis de inclusão de DDGS (0, 10, 20, 30 e 40%) utilizadas nos ensaios posteriores. O segundo ensaio consistiu na avaliação dos CDAs dos nutrientes das dietas contendo 0, 10, 20, 30 e 40% DDGS, onde juvenis de P. mesopotamicus (27±1.4 gramas) foram distribuídos em cinco tanques de fibra de vidro na densidade de 30 peixes tanque -1 em sistema de recirculação de água. Utilizou-se delineamento em Quadrado Latino, 5x5 (05 dietas e 05 períodos). Concomitantemente ao segundo ensaio, e sob o mesmo sistema de recirculação, juvenis de P. mesopotamicus (21±0.2 gramas) foram distribuídos em 20 tanques de fibra de vidro, na densidade de 15 peixes tanque -1, em DIC, e alimentados com as dietas por 100 dias. Neste terceiro ensaio foram avaliados parâmetros de desempenho produtivo, viabilidade econômica, atividade das enzimas digestivas e de estresse oxidativo do intestino, bem como morfologia intestinal dos juvenis. Os dados obtidos de desempenho produtivo, estresse oxidativo e morfometria intestinal foram submetidos à one-way ANOVA e em caso de significância (p < 0.05) foi realizado teste de Tukey adotandose 5% como nível de probabilidade. Dados de enzimas digestivas foram submetidos a two-way ANOVA e em caso de significância para interação foi feita uma one-way ANOVA e teste Tukey a 5%. Os valores obtidos para os CDA do DDGS confirmaram seu potencial de uso como ingrediente proteico em dietas para P. mesopotamicus, assim como os resultados de desempenho produtivo, onde se obteve menor valor de conversão alimentar e melhor eficiência de retenção de proteína para a dieta contendo maior nível de inclusão de DDGS (40DDGS). Os demais parâmetros de desempenho não foram afetados significativamente. A atividade das enzimas digestivas foi reduzida da porção anterior do intestino para distal e para as dietas com níveis superiores a 10% de DDGS. A inclusão de DDGS levou a redução do status oxidativo do intestino e melhoras na morfometria intestinal. Sendo assim, é possível o uso de até 40% de DDGS do milho como ingrediente proteico em dietas para juvenis de P. mesopotamicus, substituindo em totalidade o farelo de soja, mantendo os valores de desempenho produtivo, melhorando a saúde intestinal dos peixes bem como a capacidade de absorção e aproveitamento dos nutrientes disponibilizados na dieta.
Due to the increased interest in biofuels, Brazilian companies started recently, the production of ethanol from corn, generating a waste with potential for use as an ingredient in animal feed, the DDGS (dried distillers grain with soluble). As its processes results from fermentation of corn grain by yeast and enzymes, this residue has high protein and low soluble carbohydrates, which makes it good source of vegetable protein for animal feed. Besides the low cost, possible benefits related to yeast residues and other enzymes from fermentation may also contribute to DDGS market potential. Thus, this work aimed to evaluate the feasibility of inclusion of corn DDGS in diets for Piaractus mesopotamicus juveniles to replace soybean meal. To this end, there were three experimental runs. In the first assay we evaluated the apparent digestibility coefficients (ADC) of DDGS nutrients for P. mesopotamicus (13 ± 0.3 grams), distributed in a completely randomized design (CRD) in six fiberglass tanks, at density of 35 fish tank-1 in a continuous recirculating water system. The collection of feces was carried out in modified Guelph system. After obtaining the ADCs, diets were formulated with five different levels of DDGS inclusion (0, 10, 20, 30 and 40%) used in subsequent assays. The second test was the evaluation of ADCs of nutrient in the diets containing 0, 10, 20, 30 and 40% DDGS where P. mesopotamicus juvenile (27 ± 1.4 g) were distributed in five fiberglass tanks at density of 30 fish tank-1 in a recirculating water system. We used a Square Latino design, 5x5 (05 diets and 05 periods). Concomitantly to the second test, and under the same recirculation system, P. mesopotamicus juveniles (21 ± 0.2 grams) were divided into 20 fiberglass tanks, at density of 15 fish tank-1 in CRD, and fed diets for 100 days. In this third test were evaluated growth performance, economic viability, activity of digestive enzymes and oxidative stress of the intestine and intestinal morphology of juveniles. Data obtained for growth performance, oxidative stress and intestine morphology were subjected to one-way ANOVA and in case of significance (p <0.05) Tukey's test was carried out adopting a 5% probability level. Data from digestive enzymes were subjected to two-way ANOVA and in case of significance to interaction was made a one-way ANOVA and Tukey's test at 5%. The ADCs values obtained for the DDGS confirmed its potential use as a protein ingredient in diets for P. mesopotamicus, as well as the results of productive performance, which showed lower value of feed conversion ratio and an improved on protein retention efficiency for the diet containing higher inclusion level of DDGS (40DDGS). The other performance parameters were not significantly affected. The activity of the digestive enzymes was reduced from anterior to distal portion of the intestine and for diets with levels above 10% DDGS. The DDGS inclusion led to reduction of oxidative status of the intestine and improvement in intestinal morphology. Thus, the use of up to 40% corn DDGS as a protein ingredient for P. mesopotamicus juvenile is possible, replacing in whole soybean meal, keeping the growth performance, improving fish gut health as well as the absorption and utilization of nutrients available in the diet.
CNPq: 130664/2014-6
FAPESP: 2014/16685-5
FAPESP: 2015/21245-7

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