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Artykuły w czasopismach na temat "Flat fishes"
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Vendel, Ana Lúcia, Sabine Granado Lopes, César Santos i Henry Louis Spach. "Fish assemblages in a tidal flat". Brazilian Archives of Biology and Technology 46, nr 2 (marzec 2003): 233–42. http://dx.doi.org/10.1590/s1516-89132003000200015.
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Studies were carried out on fish assemblages in a tidal flat. Samples were obtained monthly at low tide of the half moon in the tidal flat of Paranaguá Bay, Brazil, with two seine nets, one with a 1 mm mesh, 30 m in length and 3 m in height and another with a 10 mm mesh, 65 m in length and 2 m in height. A total of 8,890 fish were captured, comprising 24 families and 53 species. The most abundant species were Harengula clupeola and Atherinella brasiliensis, which represented 63.4% of the total, capture. A seasonal tendency was observed in the abundance of fishes, with less fishes being captured during winter and part of spring. The number of species showed a seasonal pattern, with the gradual decrease through winter and a marked increase in summer. The community structure index indicated seasonal changes in the assemblage. The faunistic similarities between months separated the 12 months into four major groups. The seasonal pattern was apparent in the numerically dominant species and the Cluster Analysis revealed five main groups.
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Valiñas, Macarena, Eduardo M. Acha i Oscar Iribarne. "Habitat use and feeding habits of juvenile fishes in an infrequently flooded Atlantic saltmarsh". Marine and Freshwater Research 61, nr 10 (2010): 1154. http://dx.doi.org/10.1071/mf09109.
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In saltmarshes, marsh creeks provide an important corridor between the marsh and the subtidal habitat for fishes. We compare fish and prey in a Spartina densiflora marsh creek with a tidal flat in the SW Atlantic (Argentina) to evaluate the hypotheses that: (1) benthic prey abundance is higher in the marsh creek, and therefore the abundance of benthivorous fishes and predation pressure on benthos is higher in this area; and (2) marsh creeks act as refuge areas for fishes. Fish abundance and benthic prey availability were sampled over four seasons, and dietary composition of Odontesthes argentinensis and Micropogonias furnieri was assessed. Brevoortia aurea was more abundant in the marsh creek, Micropogonias furnieri showed the opposite pattern, and Odontesthes argentinensis and Ramnogaster arcuata did not dominate either habitat. As expected, smaller fishes were more abundant in the marsh creek. Food abundance was higher in the marsh creek but only M. furnieri consumed more prey in this area, while O. argentinensis consumed more in the tidal flat. Differences in prey accessibility and sediment features between areas could explain these results. This work highlights the importance of marsh creeks as refuge and/or feeding grounds for fishes in infrequently flooded saltmarshes.
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Kunishima, Taiga, i Katsunori Tachihara. "What ecological role do soft-substrate tide pools play for fishes? Difference in community structures between estuarine and coastal tidal flats in subtropical Japan". Marine and Freshwater Research 71, nr 7 (2020): 737. http://dx.doi.org/10.1071/mf19019.
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Soft-substrate tide pools are considered important habitats for fishes from an ecological perspective. However, the ecological roles of such pools and use patterns by fish remain unclear, especially regarding differences between estuarine and coastal tidal flats. In this study, quantitative sampling using the quadrat method was performed in the estuarine and coastal tidal flats on Okinawa-jima Island of subtropical Japan during four seasons. Ecological roles of soft-substrate tide pools were classified as follows: (1) permanent habitat for residents; (2) nursery ground for transients; and (3) waiting area until high tide for accidental species. Within these classifications, the ecological role and value of tide pools for transient fishes varied between the tidal flat types. The habitat value of tide pools is higher for residents than for transient species because the habitat is not replaceable for residents because of their specific ability to survive there. By contrast, transient and accidental species use the tide pools as temporary habitats; however, their high diversity affects the variation in community structure on Okinawa-jima Island. Our results suggest that we should consider not only species diversity, but also habitat use patterns of individual species, together with their life history, when evaluating habitat value with regard to conservation and management of each tidal flat.
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Yu, Fei, Jia Yuan Wang i Li Quan Xie. "Hydrodynamic Characteristics in Ecological Arc-Shaped Baffle Fishway". Applied Mechanics and Materials 212-213 (październik 2012): 1119–22. http://dx.doi.org/10.4028/www.scientific.net/amm.212-213.1119.
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Fishways are hydraulic structures allowing fishes upstream migration through engineering constructions in the rivers. The Denil type has a wide application and the main components are flat baffles. In this paper, we present a new type of baffle (arc-shaped baffle) to ameliorate the hydrodynamic characteristics in the fishway. The main improvement of arc-shaped baffle fishway is the alteration that the flat baffles are replaced by arc-baffles. In order to investigate the influence of water flow on migratory fish in the arc-baffle fishway, model tests were conducted. Based on the experimental results, the conclusion can be reached that hydrodynamic characteristics in arc-shaped baffle fishways are steadier than that in traditional Denil fishways, which makes fishes ascend easily.
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Goatley, Christopher H. R., i David R. Bellwood. "Sediment suppresses herbivory across a coral reef depth gradient". Biology Letters 8, nr 6 (24.10.2012): 1016–18. http://dx.doi.org/10.1098/rsbl.2012.0770.
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Sediments are a ubiquitous feature of all coral reefs, yet our understanding of how they affect complex ecological processes on coral reefs is limited. Sediment in algal turfs has been shown to suppress herbivory by coral reef fishes on high-sediment, low-herbivory reef flats. Here, we investigate the role of sediment in suppressing herbivory across a depth gradient (reef base, crest and flat) by observing fish feeding following benthic sediment reductions. We found that sediment suppresses herbivory across all reef zones. Even slight reductions on the reef crest, which has 35 times less sediment than the reef flat, resulted in over 1800 more herbivore bites (h −1 m −2 ). The Acanthuridae (surgeonfishes) were responsible for over 80 per cent of all bites observed, and on the reef crest and flat took over 1500 more bites (h −1 m −2 ) when sediment load was reduced. These findings highlight the role of natural sediment loads in shaping coral reef herbivory and suggest that changes in benthic sediment loads could directly impair reef resilience.
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Steinke, Dirk, Robert Hanner i Paul D. N. Hebert. "Rapid high-quality imaging of fishes using a flat-bed scanner". Ichthyological Research 56, nr 2 (8.10.2008): 210–11. http://dx.doi.org/10.1007/s10228-008-0068-8.
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Priatna, Asep, i Mohammad Natsir. "POLA SEBARAN IKAN PADA MUSIM BARAT DAN PERALIHAN DI PERAIRAN UTARA JAWA TENGAH". Jurnal Penelitian Perikanan Indonesia 14, nr 1 (6.02.2017): 67. http://dx.doi.org/10.15578/jppi.14.1.2008.67-76.
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Penelitian ini bertujuan untuk mempelajari perbedaan pola sebaran ikan pada musim barat dan peralihan di perairan utara Semarang sampai dengan Brebes, berdasarkan pada pengambilan contoh akustik dan oseanografi pada bulan Desember 2005 dan Mei 2006. Hasil menunjukkan secara spasial, pada musim barat di perairan utara Semarang sampai dengan Brebes kepadatan ikan pelagis lebih besar di daerah yang lebih dangkal yaitu sebelah selatan pada kedalaman <40 m, semakin ke tengah kepadatan semakin berkurang. Dilihat dari nilai target strength yang terdeteksi yaitu antara -60 sampai dengan -50 dB bahkan didominasi oleh ikan -60 sampai dengan -55 dB, sasaran merupakan ikan pelagis kecil yang rata-rata mempunyai ukuran 4 sampai dengan 12,5 cm. Pada musim peralihan sebaran kepadatan ikan pelagis kecil cenderung lebih merata dengan jumlah yang lebih rendah daripada jumlah ikan pada musim barat. Faktor pergerakan arah arus dan keberadaan sumber makanan yang lebih besar pada musim barat diduga merupakan penyebab perbedaan tersebut. Ikan pelagis kecil pada musim peralihan berukuran lebih besar dibandingkan ketika musim barat, dengan nilai target strength yang terdeteksi antara -60 sampai dengan -45 dB atau sekitar 4 sampai dengan 22 cm dan didominasi oleh ikan yang berukuran -55 sampai dengan -50 dB atau sekitar 7 sampai dengan 12,5 cm. Sebaran kepadatan Ikan demersal hampir merata pada ke-2 musim tersebut, pada musim peralihan kepadatan lebih rendah daripada musim barat. Ikan demersal pada musim barat terdiri atas ikan berukuran kecil (-55 sampai dengan -50 dB) atau sekitar 7 sampai dengan 12,5 cm terutama di daerah pada kedalaman <40 m, semakin ke tengah ukuran semakin besar yaitu antara -50 sampai dengan -45 dB atau sekitar 12,5 sampai dengan 22 cm. Pada musim peralihan, ikan demersal dengan target strength -55 sampai dengan -50 dB terdapat di kedalaman <40 m. Ikan demersal dengan ukuran -50 sampai dengan -45 dB mendominasi periode ini. Pada kedalaman >45 m terdeteksi ikan -45 sampai dengan -35 dB yang berkisar 22 sampai dengan 70 cm. The aim of this study is to understood the difference of fish pattern distributions at North West and intermonsoon in North of Central Java waters, based on acoustic and oceanography sampling in December 2005 and May 2006. At North West monsoon, the density of pelagic fishes was more gathering in narrower areas <40 m, and low fish density was going to middle areas. Seen from target strength the value was detected about -60 to -50 dB and it was dominated by fishes -60 to -55 dB, the targets for small pelagic fishes are about 4 to 12,5 cm. At the intermonsoon, distribution of small pelagic fishes density tends to be flat, but fish density at this time was the lower than North West monsoon. The higly current direction and food source factor at North West monsoon may cause this difference. The size of small pelagic fishes at the intermonsoon was bigger than fishes at North West monsoon, which target strength value was detected about -60 to -45 dB or 4 to 22 cm and dominated by fishes -55 to -50 dB of about 7 to 12,5 cm. The density distribution of demersal fishes almost flat at both monsoon. How ever at intermonsoon, the demersal fishes density was lower than that at North and West season. Demersal fishes at North West monsoon consisted of small fishes (-55 to -50 dB) with size of about 7 to 12,5 cm especially in narrow areas <40 m, and fish sizes the larger (-50 to -45 dB or 12,5 to 22 cm) were going to the middle areas. At intermonsoon, there were demersal fishes with target strength -55 to -50 dB at <40 m. Demersal fishes with target strength -55 to -50 dB were dominant at this time. At areas >45 m it was detected fishes of -45 to -35 dB target strength of about 22 to 70 cm.
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Kim, S. T., E. R. Ivshina i N. K. Zavarzina. "Современное состояние сырьевых ресурсов рыб в северо-восточной части Японского моря". Bulletin of the North-East Science Center, nr 4 (30.12.2022): 70–84. http://dx.doi.org/10.34078/1814-0998-2022-4-70-84.
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The commercial fish resourses in West Sakhalin waters demonstrated significant growth in the 2010s. It has been confirmed by results of trawling and egg assessment surveys as well as by the dynamics of length-age characteristics of walleye pollack, Pacific cod, Pacific herring, Pacific capelin, and flat-fishes. The important factor of the present fish resourses growing appears the favorable warming of their environment in the course of long-term periodical climate-oceanology fluctuations.
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Dadswell, Michael J., Aaron D. Spares, Erica Porter i Darren Porter. "Diversity, abundance and size structure of fishes and invertebrates captured by an intertidal fishing weir at Bramber, Minas Basin, Nova Scotia". Proceedings of the Nova Scotian Institute of Science (NSIS) 50, nr 2 (11.03.2020): 283. http://dx.doi.org/10.15273/pnsis.v50i2.10003.
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Capturing fish using a weir or trap on the intertidal flats of the Bay of Fundy was developed by native Mi’kamaq who later taught the method to the European settlers. Between 1800-1910 fish weirs were a significant part of the important American shad fishery in the inner Bay of Fundy before the collapse of the northwest Atlantic population from pollution and damming of major spawning rivers in the United States. Weirs remain an important segment of the Minas Basin fisheries but now the largest commercial catches consist of Atlantic herring, gaspereau and flounders. Studies on the fishes captured in Minas Basin weirs were published in 1852, 1924, 1984 and 2014, but all lacked a sampling intensity which would fully describe the diversity, abundance and size structure of the catch. An intertidal weir at Bramber, Minas Basin was surveyed during April-July, 2017 where catches were examined at each low tide. The weir was constructed on the intertidal flat during early April after Minas Basin cleared of drift ice. During the study period mean daily tide range was 10.46 m with a maximum spring tide range of 13.72 m. A total of eight neap and eight spring tide cycles were observed. Daily water temperature of Minas Basin was 8.0 C° during late May and increased to a maximum of 21.4 C° in late July. Fish and invertebrate collections began on April 10 and continued daily until July 22 when water temperatures in the trap became too warm for by-catch species to survive (+25 C°). During the study period an estimated total of 674,402 fishes consisting of 45 species were captured and of these 57,950 were measured. The most abundant fishes observed were gaspereau (alewife and blueback herring 51.9%), rainbow smelt (13.9%), Atlantic herring (13.0%) and tomcod (10.1%). Other commonly captured fishes were American shad, skate (little and winter), winter flounder, windowpane flounder, striped bass, mackerel and Atlantic sturgeon. A total of 18,511 invertebrates were captured and counted. The most abundant were long-fin squid (13.8%) and crustaceans (rock crab, lady crab; 84.0%). Keywords: Bay of Fundy; Canada; Clupeidae; commercial fishing; temperatures; tides
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Sazima, Ivan, Alice Grossman i Cristina Sazima. "Hawksbill turtles visit moustached barbers: cleaning symbiosis between eretmochelys imbricata and the shrimp stenopus hispidus". Biota Neotropica 4, nr 1 (2004): 1–6. http://dx.doi.org/10.1590/s1676-06032004000100011.
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This seems to be the first record of cleaning symbiosis between marine turtles and shrimps. During their foraging on the reef flat, the turtles regularly visited and posed at the stations. The same stations were visited by a few species of reef fishes, which posed and were cleaned by the shrimps. We suggest that cleaning symbiosis between turtles and shrimps is widespread and went unrecognised due to the superficial resemblance between a resting turtle and a posing and cleaned one. Additionally, we submit a putative origin for the cleaning symbiosis between marine turtles and cleaner shrimps following a few simple behavioural steps.
Rozprawy doktorskie na temat "Flat fishes"
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Brown, Stephen Nicholas. "Ecology and enhancement of the flat oyster Ostrea chilensis (Philippi, 1845) in central New Zealand". Thesis, University of Canterbury. Biological Sciences, 2011. http://hdl.handle.net/10092/6203.
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Human activities are causing a global loss of plant and animal species, degrading ecosystem properties and threatening ecosystem services. One indicator of these losses is the increasing proportion of fish stocks in decline, and the Challenger oyster fishery in Tasman Bay, central New Zealand is an example of one such fishery. Anthropogenic effects from land-based activities, and towed-gear fishing have been implicated as contributors to the decline of shellfisheries and degradation of the marine ecosystem in Tasman Bay. Increased sedimentation in the bay caused by soil erosion and runoff associated with forestry, agriculture and subdivision is likely to have a range of negative effects on the benthic community. Also towed-gear fishing, dredging and trawling homogenise benthic habitat structure (reduce habitat heterogeneity) and facilitate sediment resuspension as well as causing removal and direct physical damage to benthic biota. There is an imperative to seek to mitigate these effects and look at ways to restore the benthic community including the commercial shellfish species.
In this context, my central hypothesis was that enhancement of the benthic habitat by returning waste shell to the seabed would increase oyster production for the fishery. Related to this main goal of oyster fishery enhancement, a primary objective of the study was to fill knowledge gaps relating to the biology and ecology of the oyster in Tasman Bay. The second main topic of my thesis was to investigate how this form of habitat enhancement would alter the benthic community structure, and potentially aid in restoration of the wider ecosystem in the bay. I sought to link the twin goals of fishery enhancement and ecological restoration by considering potential management measures to promote a sustainable oyster fishery and at the same time facilitate ecological restoration within Tasman Bay. The investigations focused on four main themes: temporal patterns of oyster larval abundance, spatial patterns of spatfall and larval dispersal, effects of habitat enhancement on oyster population productivity, and effects of habitat enhancement on the benthic faunal community. Laboratory and field studies were conducted between October 2004 and May 2009.
A peak period of oyster reproductive activity began in late spring and continued through summer in each year. Maximum rates of adult oysters brooding larvae were 17% in November 2004 and 2005, and 23 % in December 2006. Over the entire summer breeding period it was estimated that 55 to 78 % of adult oysters incubated larvae. A very low level of brooding activity (1 %) occurred during winter. Temporal trends in larval settlement closely tracked brooding patterns. Settlement on collectors deployed in Tasman Bay was greatest between November and January, and there were very low rates in winter. Results are useful in optimising the timing of substratum deployment in an enhancement program for the oyster fishery.
Spat settlement density was strongly related to background adult oyster density. Spat settlement on experimental arrays deployed through the water column only occurred within a narrow vertical range very close to (<1 m above) the seabed. If suitable habitat is available for settlement, oysters tend to settle within a few hours after release, but approximately half of the larvae settled in a laboratory experiment were capable of remaining viable for several days. Oyster distribution assessed at the scale of the shellfishing industry’s annual biomass survey (median distance between sample tows ~ 1 km) is adequate to broadly predict spat settlement distribution in the subsequent settlement season, and the distribution of mature oysters is a key determinant in the placement of shell for habitat enhancement to maximise spat settlement.
Deployment of waste whole scallop shell on the seabed as settlement substratum increased oyster spat density significantly. Available settlement surface on enhanced shell plots decreased by 82% in the five months after deployment, due to fouling by numerous invertebrates and sedimentation. Survival of oysters recruited to enhanced habitat was generally very low, and varied greatly among 4 experimental sites and through time. After 3+ years, survival among site/treatment combinations ranged from 0% to 0.04%. At the site where survival was greatest, the absolute density of oysters surviving to 3.41 years on enhanced habitat was estimated as 0.4 m⁻². This equated to an increase in relative density of commercial sized oysters from ~0.01 m⁻² prior to enhancement, to ~0.14 m⁻² at the end of the experiment, and demonstrated that habitat enhancement can elevate adult oyster densities to commercial levels on areas of seabed where oysters were previously below threshold densities for commercial fishing (0.02 m⁻²). Peaks in mortality occurred within experimental plots when oysters were less than one year old, and three years old. Growth modeling indicated that after 4.25 years, 98% of living oysters would attain legal size (≥ 58mm length), and 92% would attain sufficient shell depth (≥ 20 mm) to provide high grade (grade A in the industry) meat. Shell depth was a better morphometric predictor of meat weight than either shell height or shell length.
The species assemblages on the shell-enhanced habitat were distinct from those on adjacent non-enhanced seabed. Measures of taxonomic and functional richness, faunal densities, and taxonomic redundancy within functional groups all increased in enhanced habitat. Beta and gamma diversity also increased due to patchiness of the habitat created within enhanced experimental sites. Large scale habitat enhancement in Tasman Bay via the deposition of waste shell on the seabed is likely to confer benefits to ecosystem function associated with those community level effects.
To sustain an oyster fishery in Tasman Bay, an ecosystem-based approach to fishery management is recommended to facilitate restoration of benthic habitats and communities and to help maintain ecosystem function supporting all components of the benthic community, including the oyster population. Planning and implementation of a combination of specific management measures including habitat enhancement, rotational fishing, permanent exclusion of towed fishing gear from a network of protected areas, and integration of the management of the oyster, scallop, and finfish fisheries would provide the best chance for restoration and maintenance of a sustainable oyster fishery.
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Wetherill, Julia Katherine, i Julia Katherine Wetherill. "Transformation Optics Relay Lens Design for Imaging from a Curved to a Flat Surface". Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/620729.
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Monocentric lenses provide compact, broadband, high resolution, wide-field imaging. However, they produce a curved image surface and have found limited use. The use of an appropriately machined fiber bundle to relay the curved image plane onto a flat focal plane array (FPA) has recently emerged as a potential solution. Unfortunately the spatial sampling that is intrinsic to the fiber bundle relay can have a negative effect on image resolution, and vignetting has been identified as another potential shortcoming of this solution. This thesis describes a metamaterial lens yielding a high-performance image relay from a curved surface to a flat focal plane. Using quasi-conformal transformation optics, a Maxwell's fish-eye lens is transformed into a concave-plano shape. A design with a narrower range of constitutive parameters is deemed more likely to be manufacturable. Therefore, the way in which the particular shape of the concave-plano reimager influences the range of needed constitutive parameters is explored. Finally, image quality metrics, such as spot size and light efficiency, are quantified.
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Mushili, Beverly Musonda. "Implications of Climate Variability on Small Scale Fishing Activities and the Fishers’ Adaptive Capacity in the Kafue Flats of Zambia". Diss., University of Pretoria, 2015. http://hdl.handle.net/2263/79285.
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Small scale fisheries serve as a “safety net” to the landless poor and significantly contribute to nutrition, food security, sustainable livelihood and poverty alleviation especially in developing countries such as Zambia. In spite of this substantial contribution, fisheries are highly susceptible to climate change and variability. The main aim of this study is to investigate the implications of climate variability on small scale fishing activities and the fishers’ adaptive capacity in the Kafue Flats of Zambia. Climatic data from Mumbwa, Kafue Polder, Mt Makulu, Magoye and Lusaka City meteorological stations is examined for the monthly, seasonal and annual variabilities with a central focus on the mean rainfall, temperature and wind speed over the 1982-2011 period. Additionally, the periodic size variation of the Kafue flats catchment area and its effects on the fishing activities are explored using satellite imagery in change detection analysis, employing ARC GIS 10.1 and ENVI 4.8. Further, the study explores the livelihood strategies of the fishing communities in determining their adaptive capacity to climate variability effects. Accordingly, the data sets are analysed using MS EXCEL, SPSS, ANCLIM, TREND TOOL, to establish climatic trends and deduce evidence of change and variability in the Kafue flats. Using snowball sampling technique and household survey, 110 fisher-folk were selected for the study. Besides, dissemination of face-to-face- questionnaires and key informant interviews are employed in this study. Climate variability analysis revealed that strong winds, storms, high rainfall and floods have adverse effects on the fisher-folk and their fishing activities. Thus, 90.9% of the fisher-folk indicated that heavy stormy rains have a larger potential to wreak havoc and cause death due to boat submergence. In addition, 95.5% of the fisher-folk stated that fishing activities do not take place during strong winds and heavy storms until calm weather conditions prevail. It is also established that the fisher-folk who are inclined to remain in a declining fishery are those restricted by a lack of alternative livelihoods and poverty. For instance, nearly half (44.5 %) of the fisher-folk interviewed lack alternative sources of livelihood. The conclusion from the study is that, climate variability has a wide range of impacts on fisheries and fishery dependent households. The explicit and localized impacts of climate variability on fisheries include reduced primary productivity, decrease in lake water levels and fish catches resulting from reduced precipitation and high run off. Therefore, there is need to enhance resilience and adoption of sustainable mitigation and adaptation strategies. The fisher-folk should be educated on alternative livelihoods to enable them cope in an event where climate change and variability severely impact on fisheries.Dissertation (MSc)--University of Pretoria, 2015.
Geography Geoinformatics and Mateology
MSc
Unrestricted
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Kekana, Milicent Barileng. "The impact of water and sediment quality on the health of schilbe intermedius r"uppel, 1832 and labeo rosae steindachner, 1984 at Flag Boshielo Dam, Olifants River System, Limpopo Province". Thesis, University of Limpopo (Turfloop Campus), 2013. http://hdl.handle.net/10386/1001.
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Thesis (M.Sc. (Zoology)) --University Limpopo, 2013Major anthropogenic activities such as, mining, coal-fired power stations and intensive agricultural practices in the upper catchment area of the Olifants River, have a dramatic impact on the water quality downstream. As a result the river is presently the third most polluted river in South Africa. The aim of this study was to assess the impact of water and sediment quality on the health of Labeo rosae and Schilbe intermedius. The aim was accomplished by applying the Fish Health Assessment Index (HAI) which includes the Parasite Index (PI) at Flag Boshielo Dam in the Middle Olifants River, Limpopo Province. This was achieved through; assessing the water quality of the dam by determining the levels of physical and chemical constituents in the water at three sampling sites, determining the bioaccumulation of selected metals in the muscle tissue of the two fish species, assessing the fish health (including the fish condition factor) and the fish parasites in the dam by using the fish HAI and PI, and ascertaining the Human Health risk factor upon consumption of fish contaminated with metals from the dam. The water and sediment quality were seasonally sampled at three sites in the dam: inflow, middle and wall. Dorsal muscle tissues from both fish species were collected for metal bioaccumulation analyses. The water, sediment and fish muscle tissue samples were analysed by an accredited laboratory by means of ICP-OES spectrometry. For the fish health and parasites, ten fish per species were collected seasonally (July 2009 to April 2010) by means of gill nets and examined at a field laboratory using the HAI and PI protocol. Generally the water quality of Flag Boshielo Dam was acceptable for aquatic ecosystems according to the SAWQG with the exception of phosphorus and some metals at the inflow area. The pH ranged between slightly acidic to alkaline values; water temperature: 15°C to 26°C; water hardness medium soft, salinity within the freshwater range; turbidity in the clear water range. The TDS and major ions (salts) were acceptable for the duration of the study. The highest concentrations of nutrients (specifically phosphorus) as well as metals (aluminium, cadmium, copper, iron and lead) were recorded at the inflow area of the dam. The nutrients were very low except the eutrophic range phosphorus concentrations recorded at the inflow whereby, the Elands River may be an additional source of nutrients into Flag Boshielo Dam. The metals that were recorded above TWQR are; aluminium, cadmium, copper, iron and lead, of which were mostly recorded at the inflow. However, statistically there was no significant difference among the three sampling sites. The metal concentrations at the inflow were recorded only slightly higher than the middle and the dam wall. The main source of the metals may be the water coming from catchment area of the dam given the intensive agricultural activities taking place between Loskop Dam and Flag Boshielo Dam. Sediment and bioaccumulation: All the metals were recorded at higher concentrations in the sediment than in the water and fish muscle tissue, except antimony, selenium and strontium. The most abundant metals recorded in the sediment were iron and aluminium. However, the concentrations above the TEL were cadmium, nickel and zinc. The elevated metal concentrations in the sediment are indicating that the metal load in the sediment of Flag Boshielo Dam could be a potential risk for the aquatic biota if they become bioavailable. Antimony, selenium and strontium metal concentrations were recorded at higher concentrations in the muscle tissue of both fish species than in the sediment and water. Iron was the most accumulated metal in the muscle tissue of both fish species. In terms of numbers, more metals were recorded in the muscle tissue of S. intermedius than in L. rosae however the metal concentrations were higher in the latter. This can be attributed to their different trophic levels in the food chain; L. rosae is a primary consumer while S. intermedius is a tertiary consumer. However, the metals that accumulated in the fish muscle tissue were indicative of bio-availability of the toxic metals in the dam and not water/sediment pollution. According to a Human Health risk assessment (Chapter 3), metals that may have risks upon consumption of L. rosae are; antimony, arsenic, chromium, iron and vanadium; for S. intermedius are; antimony, chromium, iron, vanadium and arsenic (in descending order). These metals may pose toxic and carcinogenic risks to humans. Therefore, the rednose labeo (L. rosae) and to a lesser extend the silver catfish (S. intermedius) fish species from Flag Boshielo Dam may not be suitable for humans if consumed above 350 g per week. Fish health and parasites: The Health Assessment Index (HAI) values of the two fish species differed significantly with higher index values recorded for S. intermedius than L. rosae. Besides the Parasite Index (PI), abnormal haematocrit readings, liver conditions, skin lesions and clubbed gills are the necropsy anomalies that contributed predominantly to the HAI. Overall, the PI contributed mostly to the total HAI value. The parasite load and therefore also the mean intensity, mean abundance and prevalence of S. intermedius were higher during all seasons than that of L. rosae. The dominant ectoparasites for both species were from the Class Monogenea and the dominant endoparasites were nematodes. Out of 40 L. rosae sampled, 139 parasites were retrieved; five parasite species were ectoparasites and two endoparasites. From the 40 S. intermedius sampled, 2473 parasites were retrieved, from which two species (one genus) were ectoparasites and three species were endoparasites. The condition factor is used to compare the “condition”, “fatness” or wellbeing of fish and it is based on the hypothesis that heavier fish of a particular length are in a better physiological condition. The L. rosae had a better condition factor, recorded at values less than (2) as compared to S. intermedius (>2). The cause of the HAI necropsy anomalies may have been also from parasite load other than the metals in the water and sediment. However, the HAI alone cannot be used for metal pollution, unless it is done in conjunction with a histopathological study of the tissues/organs. Therefore, the cause of the recorded anomalies from both fish species is inconclusive. On the hand, fish can be used as bioindicators because the accumulated metals in the fish tissues are indicative of the bioavailability of metals in Flag Boshielo Dam.
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Mogashoa, M. E. "Seasonal variation in haematological parameters and oxidative stress bio-markers for selected fish species collected from the Flag Boshielo Dam, Olifants River System, Limpopo Province, South Africa". Thesis, University of Limpopo, 2015. http://hdl.handle.net/10386/1188.
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Thesis (M.Sc. (Physiology)) --University of Limpopo, 2015Water is an essential and yet scarce resource, which has a vital role for human use and also serve as a habitat for numerous organisms in aquatic environments. Despite its scarcity there have been many reports indicating that it is continually polluted by domestic, agricultural, mining and other anthropogenic activities; subsequently affecting the health of organisms residing in such water bodies. Fish have been selected as the bio-monitoring species due to its direct interaction with the environment; thereby making it an appropriate model to monitor and evaluate the health status of the environment. The feral population of the alien species, Hypopthalmichtys molitrix (Valenciennes, 1844) commonly known as the silver carp in Flag Boshielo Dam has been considered a healthy population. However, this perception changed considerably after reports of lethargic, dying fish were first noted in 2011. Currently the sporadic deaths amongst mature specimens (>0.7m) persist; and the reason(s) for their demise remains unclear. Therefore, the aim was to employ a seasonal study design to investigate the health status of selected fish species such as H. molitrix in Flag Boshielo Dam by evaluating haematological parameters, oxidative stress biomarkers and bio-accumulation levels of particular transition metals. Seasonal surveys were carried out from February 2012 to January 2013 at Flag Boshielo Dam, Olifants River System, Limpopo Province. The locality surrounding the dam is known to be in an agriculture and mining catchment. Hypopthalmichtys molitrix and Labeo rosae (Steindachner, 1894) commonly known as the rednose labeo were collected with the use of scoop nets, conventional angling gear and gill nets. Following collection, morphometric measurements were taken and blood was collected. The blood samples required for further analysis at the Medical Science Department, University of Limpopo were kept on ice (4˚C). After the collection of all blood samples the specific fish was sacrificed and muscle samples were collected for bio-accumulation analysis and gills and liver samples were collected for the measurement of oxidative stress biomarkers. These tissue samples were rapidly frozen and kept frozen (-85˚C) until further analysis. Haematological parameters from the study reflected a variation amongst comparison of the inter- and intra-species. It was observed that mature H. molitrix suffered from anaemia. The response of glutathione-S-transferase (GST) and thiobarbituric acid reactive substances (TBARS) was relatively constant throughout all seasons when the young (<0.5m) and mature H. molitrix (0.6 – 0.90m) specimens were compared. However, the catalase (CAT) response of mature H. molitrix was dramatically impaired. This would increase their vulnerability to oxidative stress. Bioaccumulation levels of the eleven selected transition elements exhibited various trends. Metals such as Molybdenum (Mo), Vanadium (V), (Chromium) Cr, Cobalt (Co), Zinc (Zn), Cadmium (Cd) and Mercury (Hg) exhibited seasonal bio-accumulation levels that were in support of the various feeding behaviours of the fish species in this study. On the other hand, metals such as Manganese (Mn), Iron (Fe), Copper (Cu), Zinc (Zn), Cadmium (Cd) and Mercury (Hg) also illustrated the potential to be contributing factors in the death of the mature specimens. In conclusion, the findings from this study illustrate the complex nature of metabolic disturbances resulting in the death of mature H. molitrix specimens. It is clear that no single aspect investigated in this study could be solely implicated as the major cause of death. This multifactorial presentation necessitates further haematological assessment focussing on blood cell morphology and pathology, as well as investigations into other oxidative stress biomarkers in liver and gill tissue. In addition, identifying the most appropriate tissue type for future bio-accumulation measurements of transition metals in this feral population is necessitated. It is further suggested that neuro-muscular assessments, focussing on neurotransmitters such as γ-aminobutyric acid (GABA) and acetylcholine (Ach), form part of the investigation into the lethargic behaviour of the mature fish.
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Kirkland, William E. "Guiding the cell group leaders of the Fishers of Men disciplship ministry of San Jose Baptist Church, Jacksonville, Florida, to design an effective men's ministry framework". Theological Research Exchange Network (TREN), 1997. http://www.tren.com.
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Casey, John. "EFFECTS OF STEARIDONIC ACID-ENRICHED SOYBEAN OIL ON METABOLIC PROFILE AND FATTY ACID COMPOSITION IN LEAN AND OBESE ZUCKER RATS". OpenSIUC, 2013. https://opensiuc.lib.siu.edu/theses/1312.
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Background, Consumption of marine-based oils high in omega-3 polyunsaturated fatty acids (n3PUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is known to protect against obesity-related pathologies. It is less clear whether traditional vegetable oils with high omega-6 polyunsaturated fatty acid (n6PUFA) content exhibit similar therapeutic benefits. As such, this study examined the metabolic effects of a plant-based n3PUFA, stearidonic acid (SDA), in polygenic obese rodents. Methods, Lean (LZR) and obese Zucker (OZR) rats were provided either a standard westernized control diet (CON) with a high n6PUFA to n3PUFA ratio (i.e., 16.2/1.0) or experimental diet modified with flaxseed (FLAX), menhaden (FISH), or SDA oil that resulted in n6PUFA to n3PUFA ratios of 1.7/1.0, 1.3/1.0, and 1.0/0.8, respectively. Results, After 12 weeks, total adiposity, dyslipidemia, glucose intolerance, and hepatic steatosis were all greater, whereas n3PUFA content in liver, adipose, and muscle was lower in OZR vs. LZR rats. Obese rodents fed modified FISH or SDA diets had lower serum lipids and hepatic fat content vs. CON. The omega-3 index (i.e., ÓEPA + DHA in erythrocyte membrane) was 4.0, 2.4, and 2.0-fold greater in rodents provided FISH, SDA, and FLAX vs. CON diet, irrespective of genotype. Total hepatic n3PUFA and DHA was highest in rats fed FISH, whereas both hepatic and extra-hepatic EPA was higher with FISH and SDA groups. Conclusions, these data indicate that SDA oil represents a viable plant-derived source of n3PUFA, which has therapeutic implications for several obesity-related pathologies.
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Bodnarova, Adriana. "Texture analysis for automatic visual inspection and flaw detection in textiles". Thesis, Queensland University of Technology, 2000.
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Nowak, Saskia Verfasser], Jochen [Akademischer Betreuer] [Gutachter] Stark, Hans-Bertram [Akademischer Betreuer] [Fischer, Hans-Ulrich [Gutachter] Hummel i Robert J. [Gutachter] Flatt. "Alterung von Calciumsulfatphasen : Physiko-chemisch bedingte Feuchteaufnahmen und Einfluss auf die Reaktivität / Saskia Nowak ; Gutachter: Jochen Stark, Hans-Ulrich Hummel, Robert J. Flatt ; Jochen Stark, Hans-Bertram Fischer". Weimar : F. A. Finger-Institut für Baustoffkunde, 2013. http://d-nb.info/1116094533/34.
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Rawal, Kishor. "Exploring the Geomechanics of Sinkholes: A Preliminary Numerical Study". University of Toledo / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1480069621108946.
Pełny tekst źródłaKsiążki na temat "Flat fishes"
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Tate, Suzanne. Flossie Flounder: A tale of flat fish. Nags Head, NC: Nags Head Art, 1989.
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ill, Carter Andi 1976, red. Flutter and float: Bringing home goldfish. Minneapolis, Minn: Picture Window Books, 2009.
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Horn, William Pierce. Seasons on the flats: An angler's year in the Florida Keys. Mechanicsburg, PA: Headwater Books, 2012.
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Koskey, Michael Stephen. Traditional ecological knowledge and biological sampling of nonsalmon fish species in the Yukon Flats Region, Alaska. Fairbanks: Alaska Dept. of Fish and Game, Division of Subsistence, 2011.
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Andersen, David B. Whitefish and beaver ecology of the Yukon Flats, Alaska. Fairbanks, Alaska: Alaska Dept. of Fish and Game, Division of Subsistence, 2001.
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Havens, Alan C. Fish sampling, July through November 1995, in Union Flat Creek, Whitman County, Washington. Colton, Wash: Willhaven Press, 1996.
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Hansen, Patricia A. Abundance and stock composition of northern pike in Minto Flats, 1991. Anchorage, Alaska: Alaska Dept. of Fish and Game, Division of Sport Fish, 1992.
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Foster, Mark S. Castles in the sand: The life and times of Carl Graham Fisher. Gainesville, FL: University Press of Florida, 2000.
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Taube, Thomas Theodore. Seasonal migrations of northern pike in the Kaiyuh Flats, Innoko National Wildlife Refuge. Anchorage: Alaska Dept. of Fish and Game, Division of Sport Fish, Research and Technical Services, 1996.
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Genechten, Guido van. Gen xiao bai yu yi qi wan duo mao mao. Xinbei Shi: Shuang mei sheng huo wen chuang gu fen you xian gong si, 2016.
Znajdź pełny tekst źródłaCzęści książek na temat "Flat fishes"
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Koyama, Akihiko. "Coastal Fishes in Tidal Flats and Salt Marshes". W Fish Diversity of Japan, 379–94. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-7427-3_22.
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De Grandis, Mario, i Filippo Costantini. "Negotiating with the tradition: representations of fish in Alai’s fictional writing". W Studi e saggi, 111–25. Florence: Firenze University Press, 2021. http://dx.doi.org/10.36253/978-88-5518-506-6.11.
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Tibet has long been orientalized in fictional representations. Taking as a case study two texts by Alai, this paper investigates how a traditional Tibetan cultural trait–the fish taboo–is mobilized to complicate the representation of Tibetan culture. By describing the fish taboo Alai points at Tibet's cultural specificity, which in virtue of its exoticism can catch the attention of non-Tibetan readers. At the same time, however, Alai equips his characters with psychological depth, showing their contrasting inner emotions of attraction and repulsion toward fish. In this sense, Alai subtly points at the fallacies of flat representations of Tibet, thus dismantling them from within.
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Baird, Rachel J. "Measures to deter IUU Fishing in the Southern Ocean in the Absence of Flag State Control". W Reviews: Methods and Technologies in Fish Biology and Fisheries, 245–56. Dordrecht: Springer Netherlands, 2006. http://dx.doi.org/10.1007/1-4020-5339-8_9.
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"14. Fishers in the Salish Sea". W Raising the Workers' Flag, 263–71. University of Toronto Press, 2012. http://dx.doi.org/10.3138/9781442696822-016.
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Rogers, Susan Fox. "Snow Bunting". W Learning the Birds, 13–21. Cornell University Press, 2022. http://dx.doi.org/10.7591/cornell/9781501762246.003.0002.
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This chapter details the author's experience walking along the mud and rock edges of the Ashokan Reservoir to look for a Snow Bunting. Since the water from the Ashokan Reservoir glides south for over one hundred miles to supply New York City, the reservoir and the land around it are protected. The Department of Environmental Protection permits people to fish, but did not allow exploring the flats for birds. The author then went to East Kingston instead, where she finally saw some buntings. In the past forty years, Snow Bunting populations have dropped by 50 percent. Researchers do not know why, and their work is complicated by the fact that the bird breeds in such remote places. The Snow Bunting breeds in the Arctic then travels south for the winter looking for similar flat, wide-open landscapes.
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Grøttum, J. A., T. Sigholt i T. Lunde. "A flexible swimming respirometer designed for round and flat fish of different size". W Fish Farming Technology, 455–57. CRC Press, 2020. http://dx.doi.org/10.1201/9781003077770-76.
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"Early Life History of Fishes in the San Francisco Estuary and Watershed". W Early Life History of Fishes in the San Francisco Estuary and Watershed, redaktorzy Heather M. Brown, Frederick J. Griffin, Eric J. Larson i Gary N. Cherr. American Fisheries Society, 2004. http://dx.doi.org/10.47886/9781888569599.ch1.
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<em>Abstract.</em>—San Francisco Bay provides spawning and rearing habitat for California’s largest population of Pacific herring <em>Clupea pallasi</em>. This population provides a food source for other species and supports a valuable fishery for Pacific herring roe. Since the inception of the roe fishery in 1973, the California Department of Fish and Game has conducted annual surveys of spawning in San Francisco Bay as part of an ongoing assessment of population status and management of the fishery. The purpose of this paper is to document (1) regions of San Francisco Bay used by Pacific herring as spawning grounds over time, and (2) time periods in which spawning took place. Spawn data were analyzed by geographic region in the bay and by month for the period 1973–2000. During this period, we documented 269 spawning events from Point San Pablo south to Redwood City. Estimates of spawning adult biomass (fish that were not harvested by the fishery) ranged from 80,813 metric tons in 1981–1982 to 3,199 metric tons in 1997– 1998 (mean = 34,688 ± 19,325 SD). January was the peak spawning month, followed by December and February; small variations in this pattern occurred during some years. Overall, the majority of spawning took place in the north-central bay region (Point Bonita to Richmond-San Rafael Bridge, Angel Island, Point San Pablo, Berkeley flats; 55%) and the San Francisco region (Golden Gate Bridge to Candlestick Point; 34%), although it alternated between these two regions over time. In some years, considerable spawning took place in the Oakland–Alameda region (San Francisco–Oakland Bay Bridge to Bay Farm Island). The largest spawns and peak periods of spawning may not contribute most toward the next generation of Pacific herring, due to differential mortality within the season. For this reason, all regions documented in this study are important spawning grounds for Pacific herring from November through March each year. A number of recent studies have furthered our understanding of Pacific herring early life history and the forces that drive year-class formation in San Francisco Bay. However, studies are especially needed that will improve our ability to adequately address the potential impacts of human activities on Pacific herring in this highly urbanized estuary.
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Manton, Nicholas, i Nicholas Mee. "Curved Space". W The Physical World. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198795933.003.0006.
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This chapter develops the mathematical technology required to understand general relativity by taking the reader from the traditional flat space geometry of Euclid to the geometry of Riemann that describes general curved spaces of arbitrary dimension. The chapter begins with a comparison of Euclidean geometry and spherical geometry. The concept of the geodesic is introduced. The discovery of hyperbolic geometry is discussed. Gaussian curvature is defined. Tensors are introduced. The metric tensor is defined and simple examples are given. This leads to the use of covariant derivatives, expressed in terms of Christoffel symbols, the Riemann curvature tensor and all machinery of Riemannian geometry, with each step illustrated by simple examples. The geodesic equation and the equation of geodesic deviation are derived. The final section considers some applications of curved geometry: configuration space, mirages and fisheye lenses.
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Westeren, Knut Ingar. "Innovative and Knowledge Developments for Sustainability in Salmon-Based Aquaculture". W Cases on Enhancing Business Sustainability Through Knowledge Management Systems, 103–20. IGI Global, 2023. http://dx.doi.org/10.4018/978-1-6684-5859-4.ch006.
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Coastal marine salmon-based aquaculture has grown considerably in produced volumes in recent years, and projections from FAO lay out possibilities for further increases. This can only be done by introducing stronger restrictions on sustainability, including fish health and environmental regulations. To solve environmental problems, the Norwegian aquaculture company Midt-Norsk Havbruk (now Salmonor AS) received development permits in 2017 for a project based on Aquatraz semi-closed steel cages. The study is based on documentation from the Aquatraz project and interviews with employees at Midt-Norsk Havbruk. The project has mainly been successful, as in the fourth generation of the Aquatraz cage put in operation in 2021/22 delousing was not required and escape did not take place. The projects also showed how knowledge management (KM) procedures were successfully changed during implementation of new innovative technologies, the main reason for this being a flat organizational structure and focus on training and upgrading of knowledge levels and dissemination.
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"Island in the Stream: Oceanography and Fisheries of the Charleston Bump". W Island in the Stream: Oceanography and Fisheries of the Charleston Bump, redaktorzy E. L. Wenner i C. A. Barans. American Fisheries Society, 2001. http://dx.doi.org/10.47886/9781888569230.ch10.
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<em>Abstract</em>.—The geological structure and characteristic community members of four relatively distinct benthic habitats, and their associated subhabitats, are described on the upper- and middle-continental slope just north of the Charleston Bump and below the deflection of the Gulf Stream eastward. The predominant habitats, identified from submersible surveys, included moderate-relief capped mounds, moderate-relief coral mounds, low-relief substrates and cohesive-mud substrates. Moderaterelief capped-mound habitats (185–220 m) due east of Charleston, South Carolina, were characterized by high local relief (about 20 m) outcroppings having abundant and diverse fish and sessile invertebrate communities. Moderate-relief coral-mound habitats, at depths of 503–555 m southeast of Charleston, consisted of mounds of dead coral fragments with a local relief of 15–23 m. Associated with the coral mounds was a depauperate assemblage of live coral and rare fish species. Yet, this habitat had a more diverse biological community than most of the low-relief subhabitats. Low–relief habitats at 293–567 m southeast of Charleston primarily consisted of fine sediments distributed in current generated patterns. Although epibenthic fish and invertebrate species were associated with this habitat, their abundance and diversity was relatively low. Cohesive-mud habitats at 150–250 m were distributed along depth contours for a long distance. Many of the species found here were associated with widely distributed tilefish <em> Lopholatilus chamaeleonticeps </em>burrows that impart negative relief to large areas of this flat habitat.
Streszczenia konferencji na temat "Flat fishes"
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Li, Qiao, Yue Li, Yoichi Mizukami, Shuchuang Dong, Takero Yoshida i Daisuke Kitazawa. "Experimental Study on Fish-Harvest Performance of the Flexible Hose Net". W ASME 2020 39th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/omae2020-18513.
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Abstract Set net fishery is one of the efficient fishery methods and has a history of several centuries in Japan. In 2017, fish harvest amount of set net fishery was 326,200 tons, about 10.2% of the total amount in Japan. The traditional method for harvesting fish is to use two fishing vessels to haul up the box chamber and obtain the fish in it, which requires supplementary equipment and human power. For reducing human power and safety, the automated net-hauling system has been developed. This system used a flexible hose net, with air injected from one side of the hose net, then the net could float up gradually and harvest the fishes. A new hose net was developed by reducing the number of air injection tubes from seven to two in comparison to the previous hose net. The paper presents the results of the animal experiment using 1/60 model of the flexible hose net. The fish-harvest effect in the flow are experimented by the Horizontal Circulating Water Channel. The fish-harvest effect was observed directly. The floating up velocity of the hose net can affect the fish-harvest rate. If the floating up velocity is too fast, the fish are easy to be stuck on the net and cannot swim forward to arrive at the catching spot (trap net). Therefore, the floating up velocity of the hose net not only determines the operational efficiency, but also affects the fish-harvest rate to some extent. Additionally, the deformation of flexible hose net was considered not only during the air injection, but also during the water intrusion.
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Kim, Kyunghoi, Kyunghoi Kim, Oh Seok Jin, Oh Seok Jin, In-Cheol Lee i In-Cheol Lee. "CHANGES IN WATER QUALITY AND FISHERY PRODUCTION IN JINHAE BAY". W Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.31519/conferencearticle_5b1b936d7f2bd3.88169808.
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For the better understanding of long-term variations of water quality in Jinhae Bay after establishment of special law, we analyzed the archive data monitored in Jinhae Bay during the last 17 years (1997-2013). And change on fish catch due to the variations of water quality was investigated. A marked decrease in the number of red tide occurrence is due to the effectiveness of the law and sewage treatment plant that has targeted the reduction of COD in the effluent water since early 2000. Although the improvement of water quality, increase in fishery production was not observed in Jinhae Bay. For the recovery of fishery production, processes for restoration of entire ecosystem such as restoration of artificial intertidal flat and seaweed bed and remediation of organic-rich sea bed should be accompanied with improvement of water quality.
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Kim, Kyunghoi, Kyunghoi Kim, Oh Seok Jin, Oh Seok Jin, In-Cheol Lee i In-Cheol Lee. "CHANGES IN WATER QUALITY AND FISHERY PRODUCTION IN JINHAE BAY". W Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.21610/conferencearticle_58b431709cb62.
Pełny tekst źródłaStreszczenie:
For the better understanding of long-term variations of water quality in Jinhae Bay after establishment of special law, we analyzed the archive data monitored in Jinhae Bay during the last 17 years (1997-2013). And change on fish catch due to the variations of water quality was investigated. A marked decrease in the number of red tide occurrence is due to the effectiveness of the law and sewage treatment plant that has targeted the reduction of COD in the effluent water since early 2000. Although the improvement of water quality, increase in fishery production was not observed in Jinhae Bay. For the recovery of fishery production, processes for restoration of entire ecosystem such as restoration of artificial intertidal flat and seaweed bed and remediation of organic-rich sea bed should be accompanied with improvement of water quality.
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Babu, Mannam Naga Praveen, i P. Krishnankutty. "Numerical Study on Fish Tail Shaped Rudder for Improved Ship Maneuvering". W ASME 2015 34th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/omae2015-41613.
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Maneuvering is an important safety aspect in ship operations so as to avoid accident of ships in seaways and more critically in the restricted area of waterways. IMO stipulates many safety regulations on ship maneuverability in open sea conditions and the local authorities may have additional regulations in harbor, canal and other restricted waterways. The effectiveness of rudder has substantial influence on the maneuverability of a ship. It is often difficult to increase the size of the rudder, to get higher control force/moment, due to the geometrical restrictions of the aft aperture of the ship. A hydrodynamically efficient rudder section addresses this problem to some extent. Most of the fishes maneuver efficiently using their tail. The fish tail functions almost similar to that of a rudder for its movements and navigation. In general, ship with flap rudders and fish tail shaped rudders perform maneuverability better compare to a ship fitted with a conventional rudder having the same underwater surface area. In fishtail shaped rudders, the shape and movements promote good flow patterns in a wider range of rudder angles. In a fish tail, the trailing edge accelerates the flow and recovers lift over the aft section of the rudder. This results in the generation of a higher lift and thus helps in reducing the turning diameter of the vessel. The studies carried out with two rudder types — conventional rudder and fish tail shaped rudder — are presented in this paper. Numerical simulations are performed on these two rudders, both having the same surface area, for different rudder angles in free stream condition. The lift force generated by the fish tail shaped rudder is found to be higher than the conventional rudder. The flow across and the hydrodynamic forces acting on the sections are determined using a commercial CFD code. The effectiveness of the fishtail rudder is also brought out from the numerically simulated turning maneuver of a chosen ship fitted with the same rudder.
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Wang, Cun, i Qi Zhu. "Flat Half Maxwell Fish-Eye Lens for High Directivity Applications". W 2018 Asia-Pacific Microwave Conference (APMC). IEEE, 2018. http://dx.doi.org/10.23919/apmc.2018.8617471.
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Franco Delgado, Ernesto, Muhammad Talha Khan, Rao Shafin Ali Khan, Nestor Molero, Anna Gilash, Rafael Fernando Mattos, Maged Basha, Tony Laplante i Mark Szeller. "Fishing More than 8,300-ft of U-Shaped Collapsed Electric-Cable-Equipped Coiled-Tubing: A Case Study from United Arab Emirates". W SPE/ICoTA Well Intervention Conference and Exhibition. SPE, 2022. http://dx.doi.org/10.2118/209034-ms.
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Abstract (300 words) During the completion phase of an unconventional well in the United Arab Emirates (UAE), an electric-cable-equipped coiled tubing (ECE-CT) had to be cut and dropped in hole while performing a plug-and-perf campaign. The CT service provider and tool manufacturer jointly redesigned a specific fishing tool for a flat-shaped collapsed CT pipe, which allowed the latching of the U-shaped collapsed ECE-CT pipe and its safe recovery. The fish and potential solutions were analyzed by the engineering teams from operator, CT service provider, and tool manufacturer. Because of the U-shape of the fish, the existing techniques of conventional overshot for rounded profiles and flat overshot for flat-shaped profiles could not be applied. The U-shape of the fish was replicated and used to create the overshot entry guide. The prototype was manufactured and tested at surface to ensure the profile was getting inside. The tool-string included an indexing tool to allow controlled rotation, which was key to the success of that fishing operation. Upon completion of the last perforating stage in a 10-stage completion in the well, the ECE-CT pipe accidentally parted and then collapsed when it was being retrieved to surface. The CT operator activated the pipe/slips ram, but a leak was observed. The 2-in. CT pipe was cut and dropped by activating the shear/seal ram, thus leaving 8,360-ft of CT pipe in the well. A lead-impression-block (LIB) run to identify the fish profile found the U-shape fish at a depth of 6,686-ft. The electric cable did not cover the top of the fish, thus reducing the risk of the retrieval operation. Despite several attempts made with the available fishing tools for rounded profiles, even when latching was achieved, the fish was lost. Inspection of the overshot after it reached surface showed the presence of broken slips due to uneven load transmission. After analysis of both the top of fish and available fishing tools, a hybrid rounded/flat overshot was designed to allow the U-shaped CT pipe to get inside the overshot and the traveling slip to latch onto the collapsed body, allowing higher contact area and resulting in the proper latch and retrieval of the collapsed ECE-CT pipe. Because a suitable overshot was not available, the operation required designing, producing, and implementing a customized hybrid semi-rounded/flat overshot for U-shaped profiles, as well as the development of a new methodology, to successfully latch and recover the pipe. The availability of a tools manufacturer inside the country allowed a fast response, it only took 7-days to design, manufacture, and test the tool prototype, thus limiting the time the well remained idle.
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Patri, Ashutosh, i Jayanta Mukherjee. "Fish-eye shaped dielectric flat lens design utilizing 3-D printing technology". W 2016 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting. IEEE, 2016. http://dx.doi.org/10.1109/aps.2016.7696628.
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Li, Yue, Yoichi Mizukami, Takero Yoshida, Qiao Li, Jialin Han i Daisuke Kitazawa. "Experimental Study on the Motion of a Flexible Hose Net Used in Automated Net-Hauling System". W ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/omae2019-95670.
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Abstract In the set-net fishery, large amount of manpower is needed for hauling the box chamber to harvest fish. With aging problem and labor insufficiency, the labor-intensive net-hauling method faces the problems of lower production, lower efficiency and higher operational risk. An automated net-hauling system using the flexible hose net which is installed in the box chamber is being developed to solve such problems. With air injected from one edge of the hose net, the hoses are inflated and the buoyancy force increases, the net floats up gradually, cornering the fish in the other edge. To corner and harvest the fish efficiently and safely, the deformation and the motion parameters of the hose net are of significance. This paper presents the results of the water tank experiment using 1/6 scale model, which was conducted to analyze the deformation of the hose net with different volumes of air in, the time spent for floating up and sinking down and the average velocities of sinking and floating processes. The results showed that when the attached weight reached 42.5% of the maximum buoyancy force of the hose net, the net could float up gradually in an ideal form and sink down smoothly through natural exhaust and stretched on the bottom of the water tank. The time spent and average velocities in floating up and sinking down processes varied with air pressure and air flow rate, making it possible to control the motion of the hose net by adjusting the air flow in practical operation.
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Subramanian, Saravanakumar, Thomas George i Asokan Thondiyath. "Hardware-in-the-Loop verification for 3D obstacle avoidance algorithm of an underactuated flat-fish type AUV". W 2012 IEEE International Conference on Robotics and Biomimetics (ROBIO). IEEE, 2012. http://dx.doi.org/10.1109/robio.2012.6491023.
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Kitazawa, Daisuke, Yoichi Mizukami, Masaaki Isobe, Hiromi Kinoshita, Mamoru Hirayama, Satoshi Ikeda i Yoto Takeuchi. "Tank Model Testing of a Fish-Cage Flotation/Submersion System Using Flexible Hoses". W ASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2011. http://dx.doi.org/10.1115/omae2011-50240.
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A fish-cage flotation/submersion system using flexible hoses is proposed to achieve horizontally stable floating and sinking motions. Waterproof flexible hoses are inserted into polyethylene pipes installed at the top of the frame of the fish cage. These hoses flatten when they are devoid of air and water as the fish cage is submerged. The injection of high-pressure air regenerates buoyancy and enables the fish cage to rise in the water. The advantage of this system is the uniform, circumferential generation of buoyancy at the top of the frame, which suppresses inclination of the fish cage and concomitant deformation of the flexible chemical fiber nets. Tank model testing was carried out to examine the inclination and the floating velocity of the fish cage. Tauchi’s similarity law was applied to make a 1/30 model of the full-scale fish cage. The tank model of the fish cage was installed in the ocean engineering basin at the University of Tokyo, and it was made to float and sink in water with and without currents. The inclination and position of the fish cage were measured using video camera images. As a result, the proposed fish cage was observed to float stably in still water in contrast to systems based on the existing method. When subjected to water currents, the new fish cage inclined by a maximum of 18° just after leaving the bottom; the inclination was reduced with further ascension. The ratio of buoyancy to gravity, the rate of air injection, and the arrangement of the flexible hoses should be optimized to achieve a more stable motion. The floating velocity for the rising fish cage in still water was then analyzed. The drag coefficient of the fish cage, as calculated from experimental data, corresponded to that estimated from a structural analysis of the fish cage. Analysis projected accelerated motion for 0.02 s after the fish cage rose from the bottom, while acceleration lasted a few seconds in the tank model test. This is because uniformly accelerated motion was assumed in the analysis, while the acceleration actually varies from zero to a constant acceleration, because of the difference between gravity and the varying buoyancy of the flexible hoses.
Raporty organizacyjne na temat "Flat fishes"
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ARMY ENGINEER DISTRICT SACRAMENTO CA. Pine Flat Dam Fish and Wildlife Habitat Restoration, Fresno, California. Fort Belvoir, VA: Defense Technical Information Center, grudzień 2001. http://dx.doi.org/10.21236/ada403359.
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ARMY ENGINEER DISTRICT SACRAMENTO CA. Pine Flat Dam Fish and Wildlife Habitat Restoration, Fresno, California. Final Environmental Impact Statement/Environment Impact Report (SCH #96042044). Fort Belvoir, VA: Defense Technical Information Center, grudzień 2001. http://dx.doi.org/10.21236/ada406366.
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ARMY ENGINEER DISTRICT SACRAMENTO CA. Pine Flat Dam Fish and Wildlife Habitat Restoration, Fresno, California. Appendix C. Basis of Design and Cost Estimate Office Report. Fort Belvoir, VA: Defense Technical Information Center, grudzień 2001. http://dx.doi.org/10.21236/ada406461.
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