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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.
Testo completo
2
Bolland, Samuel John. "Describing new species of Cryptosporidium in fish". Thesis, Bolland, Samuel John (2019) Describing new species of Cryptosporidium in fish. Honours thesis, Murdoch University, 2019. https://researchrepository.murdoch.edu.au/id/eprint/54961/.
Testo completoAbstract (sommario):
The protozoan parasite Cryptosporidium (class Gregarinomorphea, subclass Cryptogregaria) causes a range of symptoms in humans and clinical signs in animals from asymptomatic to severe diarrhoea and death. However, relatively little information is available regarding the taxonomy, zoonotic potential and host relationships of Cryptosporidium in fish. Previous studies have indicated that extensive genetic diversity exists with piscine Cryptosporidium species and genotypes. The present study screened fish from two sources in Perth, Western Australia; Water Garden Life Fish Farm (n=233) and Vebas Aquarium (n=234) for Cryptosporidium. Intestinal and gastric tissue was dissected out and screened by PCR and Sanger sequencing using Cryptosporidium specific primers that amplify DNA at the 18S and actin loci. Samples that were positive by PCR were also screened by histology. The overall prevalence of Cryptosporidium was 4.3% (20/467, 95% CI: 2.6-6.5). Phylogenetic analyses of 18S sequences identified C. huwi (n=11), piscine genotype 2 (n=3), piscine genotype 4 (n=1) and piscine genotype 7 (n=5). In addition, ten novel sequences most genetically similar to species from the genus Goussia and a sequence from the non-parasitic alveolate Colpodella were identified. Sequences amplified at the actin locus were C. huwi (n=7), piscine genotype 2 (n=1), piscine genotype 7 (n=1) and one novel Cryptosporidium sequence. Piscine genotype 2 was most closely related to piscine genotype 4 (4.1% genetic distance) and exhibited 11.1-11.9%, 15.3% and 22.3% genetic distances from C. molnari, C. huwi and C. scophthtalmi, respectively. At the actin locus, piscine genotype 2 was again most closely related to piscine genotype 4 (7.2% genetic distance) and exhibited genetic distances ranging from 18.1% (C. molnari) to 20% (C. huwi) and 26.1% for C. scophthalmi, respectively, and 20.7%- 32% genetic distance from all other species. Phylogenetic analysis of concatenated 18S and actin sequences showed that piscine genotype 2 exhibited 14% (C. molnari) to 24.6% (C. canis) genetic distance from all other Cryptosporidium spp. Using concatenated sequences, piscine genotype 7 was most closely related to C. huwi at a genetic distance of 7.5% and exhibited 13.4% (C. molnari) to 23.1% (C. scophthalmi) genetic distances from other piscine Cryptosporidium species, with 17.9% (C. testudinis) to 22.6% (C. canis) genetic distance from all non-piscine Cryptosporidium species. Piscine genotype 2 exhibited 14.6% genetic distance from piscine genotype 7. These genetic distances at two separate loci confirm the genetic distinctness of piscine genotype 2 and piscine genotype 7 and indicate that they are likely novel species. Additionally, 10/467 (2.1%, 95% CI; 1.0-3.9) samples that were positive at the 18S locus, produced sequences most genetically similar to species from the genus Goussia, subclass Conoidasida, nine were novel sequences and were compared at the 18S locus to established species of Goussia and genetic distances between 1.9% and 14.8% were identified, adding to the diversity of this genus. Furthermore, Schyzocotyle acheilognathi, the invasive Asian fish tapeworm, was identified (n=2) by morphology infecting goldfish from a local fish farm. This is only the second report of S. acheilognathi in Western Australia as it was first discovered in 2018 by a Murdoch researcher in feral goldfish from a Lake in Joondalup. Analysis at additional loci or whole genome sequencing will shed more light on the evolutionary relationships between Cryptosporidium species, while next generation sequencing would elucidate the prevalence of mixed infections of Cryptosporidium in fish. The genetic data produced by the present study describes two piscine genotypes of Cryptosporidium (that are likely valid species) in detail and provides new genetic data on the diversity of Goussia spp.
Keywords: Cryptosporidium, 18S, actin, Schyzocotyle acheilognathi, Goussia
3
Wise, Brent Stephen. "Age composition and growth rates of selected fish species in Western Australia". Thesis, Wise, Brent Stephen (2005) Age composition and growth rates of selected fish species in Western Australia. PhD thesis, Murdoch University, 2005. https://researchrepository.murdoch.edu.au/id/eprint/410/.
Testo completoAbstract (sommario):
Growth typically varies considerably amongst the individuals in a population and between individuals in different populations of the same species, especially when those populations are found in environments in which the characteristics differ markedly. Although the annuli in hard structures are often used to age fish, such growth zones are not always clearly defined in these structures. Thus, in these cases, it is necessary to use alternative methods for ageing, such as analysis of modal progressions in length-frequency data. However, these types of techniques can usually only identify distinct size classes that correspond to an age class. They thus only enable an individual fish to be aged when it is a member of a discrete size cohort. Such a situation generally only applies to the younger age classes. This thesis reports the results of studies on a species that can be aged using the annuli in one of its hard parts (asteriscus otoliths), i.e. Cnidoglanis macrocephalus, and four species (Amniataba caudavitatta, Apogon rueppellii, Pseudogobius olorum and Favionigobius lateralis) for which it was necessary to use a method such as length-frequency analysis for ageing.
Cnidoglanis macrocephalus is an important recreational and commercial species caught in coastal marine and estuarine environments in south-western Australia. However, all previous detailed studies on the age and growth on this species have focused on estuarine populations. This thesis reports the results of a study of the biology of C. macrocephalus in Princess Royal Harbour, a marine embayment on the south coast of Western Australia. Samples of C. macrocephalus were collected from amongst the macroalgae that were removed from this highly eutrophic embayment by mechanical harvesters. Analysis of the reproductive and size composition data derived from these catches showed that spawning occurs between October and December and that fecundity ranged from 75 in a 384 mm fish to 465 in a 443 mm fish. Small fish (<200 mm) were rarely caught, reflecting the fact that the young of this species are difficult to capture.
Analysis of the trends exhibited by the marginal increments on otoliths showed that the number of annuli on this hard structure could be used to age C. macrocephalus. The samples of C. macrocephalus collected from Princess Royal Harbour contained female and male fish that had lived for up to 10 and 9 years in age and reached maximum lengths and weights of 523 mm and 745.3 g and 557 mm and 735.8 g, respectively. To overcome the paucity of small fish, von Bertalanffy growth curves were constructed using back-calculated lengths and employing the scale proportional hypothesis and body proportional hypothesis (see Francis 1990). The growth rates of females and males were slower than those in a nearby seasonally closed estuary (Wilson Inlet) and in a permanently open estuary on the lower west coast of Australia (Swan River Estuary). Yield per recruit analyses were conducted in order to ascertain what minimum legal lengths were appropriate for the capture of C. macrocephalus in Princess Royal Harbour, the Swan River Estuary and Wilson Inlet in order to sustain the stocks in those water bodies.
The age and growth of Amniataba caudavittata and Apogon rueppellii in the Swan River Estuary were determined by analysing the trends exhibited by modes in sequential monthly length-frequency data. This was achieved by employing MULTIFAN, which constrained the means of the lengths of the cohorts in successive monthly samples to a seasonal form of the von Bertalanffy growth curve. The resulting growth parameters derived by MULTIFAN were similar to those derived from the growth curves fitted to the means of the cohorts determined independently for each monthly sample by MIX.
The discreteness of the distributions and modes of size classes in length-frequency data for A. caudavittata and A. rueppellii enabled sound growth curves to be constructed for both of these species. The growth curves of these two sexes of both species were significantly different, with K being lower and L being higher for females. The trends exhibited by these growth curves emphasised that the growth of both species is highly seasonal, with little or no increase in length occurring during the cooler part of the year. The seasonal von Bertalanffy growth equations implied that 'negative growth' occurred in winter, but this is an artefact produced by size-related differences in offshore movements that occur at that time of the year.
The age and growth of two further species from the Swan River Estuary, Pseudogobius olorum and Favonigobius lateralis, were also studied. Since P. olorum and F. lateralis both spawn at different times of the year and these times (spring and autumn) are not regularly spaced during the year, they produce new 0+ recruits at two irregularly-spaced times of the year. Consequently, MUTLIFAN cannot be used to analyse the size-distribution data for these two gobiid species. Thus, MIX was used to identify the size classes present in sequential samples and to provide means for the length distributions of those size classes. von Bertalanffy growth equations were then fitted to the mean lengths at the inferred age of the males and females of each size class of each species. It was found appropriate to use the traditional von Bertalanffy growth curve for describing the growth of the product of the spring-spawning group of both species and a seasonal von Bertalanffy growth curve for that of the product of the autumn-spawning groups of both species.
The growth curves, when considered in conjunction with the trends exhibited by reproductive variables, demonstrate that female F. lateralis attains sexual maturity more rapidly and at a larger size than P. olorum. The majority of the female and male progeny of the summer and autumn-spawning groups of F. lateralis reach maturity when they are approximately 3 1/2 and 8 1/2 months old, respectively, compared with five and seven months old, respectively, for P. olorum.
Models, incorporating data on water temperature and salinity and the growth and reproduction characteristics of P. olorum and F. lateralis, were used to postulate how environmental factors might be regulating when these two gobiid species spawn. The results of these models support the conclusion that the bimodal timing of spawning of P. olorum in the upper estuary was regulated by water temperature, with spawning occurring between 20 and 25oC but inhibited by temperatures greater than 25oC. They also showed that, although water temperature also influenced the timing of spawning of F. lateralis in the lower estuary, the onset of spawning by this species only occurred when salinities had reached 300/00.
4
Wise, Brent Stephen. "Age composition and growth rates of selected fish species in Western Australia". Wise, Brent Stephen (2005) Age composition and growth rates of selected fish species in Western Australia. PhD thesis, Murdoch University, 2005. http://researchrepository.murdoch.edu.au/410/.
Testo completoAbstract (sommario):
Growth typically varies considerably amongst the individuals in a population and between individuals in different populations of the same species, especially when those populations are found in environments in which the characteristics differ markedly. Although the annuli in hard structures are often used to age fish, such growth zones are not always clearly defined in these structures. Thus, in these cases, it is necessary to use alternative methods for ageing, such as analysis of modal progressions in length-frequency data. However, these types of techniques can usually only identify distinct size classes that correspond to an age class. They thus only enable an individual fish to be aged when it is a member of a discrete size cohort. Such a situation generally only applies to the younger age classes. This thesis reports the results of studies on a species that can be aged using the annuli in one of its hard parts (asteriscus otoliths), i.e. Cnidoglanis macrocephalus, and four species (Amniataba caudavitatta, Apogon rueppellii, Pseudogobius olorum and Favionigobius lateralis) for which it was necessary to use a method such as length-frequency analysis for ageing.
Cnidoglanis macrocephalus is an important recreational and commercial species caught in coastal marine and estuarine environments in south-western Australia. However, all previous detailed studies on the age and growth on this species have focused on estuarine populations. This thesis reports the results of a study of the biology of C. macrocephalus in Princess Royal Harbour, a marine embayment on the south coast of Western Australia. Samples of C. macrocephalus were collected from amongst the macroalgae that were removed from this highly eutrophic embayment by mechanical harvesters. Analysis of the reproductive and size composition data derived from these catches showed that spawning occurs between October and December and that fecundity ranged from 75 in a 384 mm fish to 465 in a 443 mm fish. Small fish (<200 mm) were rarely caught, reflecting the fact that the young of this species are difficult to capture.
Analysis of the trends exhibited by the marginal increments on otoliths showed that the number of annuli on this hard structure could be used to age C. macrocephalus. The samples of C. macrocephalus collected from Princess Royal Harbour contained female and male fish that had lived for up to 10 and 9 years in age and reached maximum lengths and weights of 523 mm and 745.3 g and 557 mm and 735.8 g, respectively. To overcome the paucity of small fish, von Bertalanffy growth curves were constructed using back-calculated lengths and employing the scale proportional hypothesis and body proportional hypothesis (see Francis 1990). The growth rates of females and males were slower than those in a nearby seasonally closed estuary (Wilson Inlet) and in a permanently open estuary on the lower west coast of Australia (Swan River Estuary). Yield per recruit analyses were conducted in order to ascertain what minimum legal lengths were appropriate for the capture of C. macrocephalus in Princess Royal Harbour, the Swan River Estuary and Wilson Inlet in order to sustain the stocks in those water bodies.
The age and growth of Amniataba caudavittata and Apogon rueppellii in the Swan River Estuary were determined by analysing the trends exhibited by modes in sequential monthly length-frequency data. This was achieved by employing MULTIFAN, which constrained the means of the lengths of the cohorts in successive monthly samples to a seasonal form of the von Bertalanffy growth curve. The resulting growth parameters derived by MULTIFAN were similar to those derived from the growth curves fitted to the means of the cohorts determined independently for each monthly sample by MIX.
The discreteness of the distributions and modes of size classes in length-frequency data for A. caudavittata and A. rueppellii enabled sound growth curves to be constructed for both of these species. The growth curves of these two sexes of both species were significantly different, with K being lower and L being higher for females. The trends exhibited by these growth curves emphasised that the growth of both species is highly seasonal, with little or no increase in length occurring during the cooler part of the year. The seasonal von Bertalanffy growth equations implied that 'negative growth' occurred in winter, but this is an artefact produced by size-related differences in offshore movements that occur at that time of the year.
The age and growth of two further species from the Swan River Estuary, Pseudogobius olorum and Favonigobius lateralis, were also studied. Since P. olorum and F. lateralis both spawn at different times of the year and these times (spring and autumn) are not regularly spaced during the year, they produce new 0+ recruits at two irregularly-spaced times of the year. Consequently, MUTLIFAN cannot be used to analyse the size-distribution data for these two gobiid species. Thus, MIX was used to identify the size classes present in sequential samples and to provide means for the length distributions of those size classes. von Bertalanffy growth equations were then fitted to the mean lengths at the inferred age of the males and females of each size class of each species. It was found appropriate to use the traditional von Bertalanffy growth curve for describing the growth of the product of the spring-spawning group of both species and a seasonal von Bertalanffy growth curve for that of the product of the autumn-spawning groups of both species.
The growth curves, when considered in conjunction with the trends exhibited by reproductive variables, demonstrate that female F. lateralis attains sexual maturity more rapidly and at a larger size than P. olorum. The majority of the female and male progeny of the summer and autumn-spawning groups of F. lateralis reach maturity when they are approximately 3 1/2 and 8 1/2 months old, respectively, compared with five and seven months old, respectively, for P. olorum.
Models, incorporating data on water temperature and salinity and the growth and reproduction characteristics of P. olorum and F. lateralis, were used to postulate how environmental factors might be regulating when these two gobiid species spawn. The results of these models support the conclusion that the bimodal timing of spawning of P. olorum in the upper estuary was regulated by water temperature, with spawning occurring between 20 and 25oC but inhibited by temperatures greater than 25oC. They also showed that, although water temperature also influenced the timing of spawning of F. lateralis in the lower estuary, the onset of spawning by this species only occurred when salinities had reached 300/00.
5
Henriksson, Anna. "Biotic resistance in freshwater fish communities". Doctoral thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-110251.
Testo completoAbstract (sommario):
Invasions of non-native species cause problems in ecosystems worldwide, and despite the extensive effort that has been put into research about invasions, we still lack a good understanding for why some, but not other, communities resist these invasions. In this doctoral thesis I test hypotheses on biotic resistance using a large dataset of more than 1000 both failed and successful introductions of freshwater fish into Swedish lakes. We have found that the classic species richness hypothesis is a poor descriptor of introduction success because it fails to acknowledge that resident species contribute to the resistance in different ways. We developed a new measure of biotic resistance, the weighted species richness, which takes into account that the resident species contributes to the resistance with different strength and sign. Further, we correlated performance traits of species in their role as an invader and as a resident species to predict how the biotic resistance of these communities would develop over time. We found a positive correlation between performance traits: Some species have high introduction success, they make a large contribution to the resistance, and they cause extinctions when introduced but do not go extinct themselves when other species establishes, whereas other species are weak performers in these respects. Thus, the biotic resistance of these communities should grow stronger as non-native species accumulates. These results give us clues about what type of communities that should be most sensitive to further invasions, i.e., communities harboring species weak performers. My results show that the biotic resistance of communities is an important factor in determining invasibility of a community. They also show that methods for quantifying resistance must take into account how interactions are structured in nature. What determine the biotic resistance of a community is the type of interactions that the resident species have with the invader and not the species richness of the community.
6
Lazo, Zamalloa Oxana. "Development of new products from aquaculture fish species". Doctoral thesis, Universitat de Girona, 2018. http://hdl.handle.net/10803/471460.
Testo completoAbstract (sommario):
Europeans are regular consumers of fish and aquaculture products. Therefore, five species of potential aquaculture rearing named: Meagre, Pikeperch, Grey Mullet, Greater Amberjack and Wreckfish were selected for new product development. This work incorporated opinions of both experts and naïve assessors thus, including specific demands and consumer preferences, in selected markets of the European Union (UK, Germany, Spain, France and Italy). Different fish product prototypes were developed from the fish species accordingly with suggested ideas and based on the physicochemical and sensory properties of the selected species. Six of these products were chosen, based on their level of processing and addressed market. Consumers perception of all six of them was also assessed in the five selected countries. As it turned out the image/perception of the different products, differed in an important way between countries, as well as their impact on the product acceptance and purchase probabilityLos pasíses de la Unión Europea son consumidores habituales de productos de acuicultura. Es por ello que, se seleccionaron cinco especies con potencial acuícola: Corvina, Lucioperca, Mújol, Seriola y Cherna para el desarrollo de nuevos productos. Este trabajo incluyó opiniones tanto de expertos como de consumidores habituales, incluyendo asñi demandas específicas y preferencias en mercados seleccionados de la UE (Alemania, España, Francia, Italia y Reino Unido. Se desarrollaron distintos prototipos de productos basados en ideas sugeridas y en las propiedades fisicoquímicas y sensoriales de las especies. Seis de estos fueron seleccionados basados en su nivel de procesamiento y mercado. La percepción de consumidores sobre los productos fue evaluada en los 5 países de la UE.La percepción de la imagen de los productos difirió notablemente entre países, así como en la aceptabilidad e intención de compra
7
Fugère, Vincent. "Electric signals and species recognition in gymnotiform fish". Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=86810.
Testo completoAbstract (sommario):
Gymnotiformes are South American weakly electric fish that produce weak electric organ discharges (EOD) for orientation, foraging and communication purposes. Because EOD properties vary widely across species, electric signals could serve a species recognition function. We quantified the electric signals of various species and used discriminant function analyses to verify whether these signals are species-specific based on different signal parameters. We found that the EOD waveform was a more specific cue than EOD frequency. Using Apteronotus leptorhynchus as a focal species, we complemented these measurements with playback experiments using stimuli of different species (varying in frequency, waveform, or both). In both a free-swimming experiment and a communication assay with restrained fish, we found that the subjects' behaviour was strongly influenced by the frequency of the stimuli but, opposite to what we predicted, the waveform of the stimuli had no measurable effect on either communication or locomotor behaviors.Les gymnotes sont des poisons faiblement électriques d'Amérique du Sud utilisant leur électro-sens à des fins de navigation, d'approvisionnement et de communication. Les décharges électriques varient énormément d'une espèce à l'autre et pourrait ainsi être utilisées pour la reconnaissance des espèces. Nous avons quantifié la décharge de plusieurs espèces et avons utilisé des analyses discriminantes afin de vérifier si les décharges sont spécifiques aux espèces selon différents paramètres. La forme de la décharge semble plus spécifique que la fréquence de celle-ci. Pourtant, en réalisant des expériences comportementales avec le gymnote Apteronotus leptorhynchus et des stimuli de différentes espèces, nous avons découvert que le comportement des sujets varie beaucoup en fonction de la fréquence du stimulus alors que, contrairement à ce que nous avions prédis, la forme de la décharge du stimulus n'eut aucun impact mesurable sur les comportements moteurs ou communicatifs des sujets.
8
Diffoot, Nanette. "Corydoras aeneus: a diploid-tetraploid fish species complex". Thesis, Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/101468.
Testo completoAbstract (sommario):
Corydoras aeneus is an armoured catfish found in the upper amazon regions of South America. It is a member of the family Callichthyidae. Studies done with this species of fish showed that C. aeneus is a tetraploid with a chromosome number of 132 (Scheel et al. , 1972). Dunham et al. (1980) reported 120 chromosomes. The C. aeneus used in this study were bought from direct importers. We had four samples of fishes supposedly coming from Brazil (Belem), Guyana, Peru and Trinidad. During our initial studies in an attempt to karyotype aeneus we came across individuals with a highly reduced chromosome number. A diploid form of C. aeneus was discovered. Only those fishes from our Belem sample were diploid. A comparison of the diploid and tetraploid forms was done. Both forms were karyotyped, the tetraploid form of C. aeneus has 134 chromosomes and the diploid has 56. Physically both forms looked exactly the same. Morphometric as well as meristic data was collected from 131 fishes and analyzed by multivariate, discriminant and contingency chi- square analyses. The results obtained do not suggest any absolute morphological differences between the diploid and the tetraploid forms anymore than between tetraploids.M.S.
9
Pyle, Gregory G. "The toxicity and bioavailability of nickel and molybdenum to standard toxicity-test fish species and fish species found in northern Canadian lakes". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ63914.pdf.
Testo completo
10
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.
Testo completoAbstract (sommario):
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
TESIS
11
Cunningham, Carey O. "Molecular methods of distinguishing Gyrodactylus species parasitising salmonid fish". Thesis, University of Aberdeen, 1995. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU068351.
Testo completoAbstract (sommario):
Gyrodactylus salaris Malmberg, 1957, a monogenean parasite of salmonid fish, has caused the death of up to 95% of salmon parr in 37 Norwegian rivers. In order to prevent further spread of this parasite, a reliable method of identifying G. salaris and distinguishing it from other closely related species is required. This study, the first investigation of Gyrodactylus genetics, has demonstrated that DNA technology can provide methods of gyrodactylid species identification suitable for routine use. DNA was extracted from G. salaris and two other species common on salmonid fish; G. derjavini and G. truttae. The small subunit ribosomal RNA (srRNA) gene was amplified from this DNA by polymerase chain reaction (PCR). The complete nucleotide sequence of the srRNA gene from G. salaris was determined. This was used to predict a secondary structure for gyrodactylid srRNA and to construct molecular phylogenies of platyhelminths including Gyrodactylus. Fragments of the srRNA gene from each species were compared by Denaturing Gradient Gel Electrophoresis. Mobility differences in G. truttae fragments were found and one fragment showed variation between and within species. The V4 region of srRNA was amplified from single specimens of gyrodactylids using a combined lysis and PCR reaction and sequenced. Examination of these sequences enabled prediction of Restriction Fragment Length Polymorphisms (RFLPs) between species and the design of oligonucleotide probes specific for each species. Digestion of the srRNA gene V4 region with two restriction enzymes produced restriction fragment polymorphisms that can be used to discriminate between G. salaris, G. derjavini and G. truttae. The digoxigenin labelled oligonucleotides GsV4, GdV4 and GdV4 are specific for G. salaris, G. derjavini and G. truttae respectively and can detect PCR amplified DNA from single specimens in dot blots. Both RFLP and probe methods of identifying Gyrodactylus species are suitable for use in diagnostic laboratories.
12
Orchard, Trevor Jonathan. "The role of selected fish species in Aleut paleodiet". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ62559.pdf.
Testo completo
13
Johansson, Ulf. "Stream channelization effects on fish abundance and species composition". Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-97292.
Testo completoAbstract (sommario):
Streams are important habitats, providing shelter and feeding opportunities for a wide range of organisms. The species depending on running waters includes a wide array of fish species, using these waters for their whole or parts of their lifecycle. Streams are also the subject of different anthropogenic impact, e.g. hydropower development. Hydropower development usually means lost connectivity, altered flow regimes and channelization. Channelization is one of the major factors causing stream habitat loss and degradation and thereby a threat to biodiversity of running waters. In the present study, the ecological impact of channelization on the fish fauna along a gradient of channelization severeness was examined. Besides channelization, stream velocity and depth were taken in to account. The study was carried out in two adjacent nemoboreal streams, Gavleån and Testeboån. The study was conducted between the 6th of June and the 10th of October 2012 at 15 sites. Sites were selected using historical maps and field observations and graded 0-3 depending on the degree of channelization. Fish community were sampled with, Nordic multi-mesh Stream Survey Net (NSSN). In all, 1.465 fish were captured, representing 15 species and seven families. The sites differed in species richness, abundance and proportion of individuals. Based on the results from rarefaction curves and ANOVA, channelization was found to be the main factor affecting the fish biota, both in abundance as well as species richness and composition. In general the rheophilic species declined along the gradient of increasing channelization severeness, while limnophilic species increased
14
Lefkaditis, Dionysios. "Intelligent visual otolith classification for bony fish species recognition". Thesis, University of Brighton, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.500781.
Testo completoAbstract (sommario):
The study of otoliths is a well-established source of information for understanding the life offish and fish populations. Conducting fish species identification from otolith samples found in the stomach contents of marine fish-eating animals finds interesting applications such as dietary studies, stock monitoring, assessment and management. Fish species identification can provide useful data for climatology, archaeology and palaeontology research, as otoliths can be sourced from geological sediments or archaeological excavations. Analysing an otolith is a highly complex and time-consuming procedure Therefore, an automated otolith classification system can prove to be a vital tool for a wide variety of scientific research. The aim of the programme of work seeks the development of a novel automated fish species identification system. The main focus of this investigation is on the commercially interesting fish of the Northern Aegean Sea. The methodology described in this thesis exploits the inherent shape variability offish otoliths according to their corresponding species. This is based on the processing and analysis of images acquired using a stereoscopic microscope fitted with a digital camera. A compact feature vector is then constructed out of a list of candidate descriptors derived from the morphology as well as the image statistics of the otoliths. The identification is carried out by an intelligent classifier based on an artificial neural network. Several configurations of multi-layer perceptron, radial basis function and hybrid neural networks are considered in pursuit of a practical and expandable classification system.
15
Wearmouth, Victoria Jayne. "Mechanisms underlying sexual segregation in a monomorphic fish species". Thesis, University of Bristol, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.437306.
Testo completo
16
Gibbons, Wade N. "Suitability of small fish species for monitoring the effects of pulp mill effluent on fish populations". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq21350.pdf.
Testo completo
17
Raitaniemi, Jari. "The growth responses of fish to differences in acidity-related lake characteristics and fish species composition". Helsinki : University of Helsinki, 1999. http://ethesis.helsinki.fi/julkaisut/mat/ekolo/vk/raitaniemi/.
Testo completo
18
Carden, Kerilynn M. "Macrophytes as fish habitat : the role of macrophyte morphology and bed complexity in fish species distributions /". Link to abstract, 2002. http://epapers.uwsp.edu/abstracts/2002/Carden.pdf.
Testo completo
19
Edwards, Christopher J. "Recreational Angler Perspectives of Nonnative Fish Species and Mercury Advisories". FIU Digital Commons, 2013. http://digitalcommons.fiu.edu/etd/1035.
Testo completoAbstract (sommario):
The central Everglades serve as a Wildlife Management Area and as a Water Conservation Area for the Miami-Fort Lauderdale metropolitan area. It is also home to over 22 nonnative freshwater fish species and carries restrictive fish consumption guidelines for Mercury. In my study, boat anglers and canal bank anglers were personally interviewed in the field, to research their awareness and perspectives of these potential environmental and health threats. The study found 78% of anglers were aware of the presence of nonnative fish species, but favored native fish species, and that 69% were aware of mercury advisories, but did not eat fewer fish because of them. Demographic characteristics were found to predict awareness, which differed significantly between angler types. Public awareness campaigns of nonnative fish impacts should target high school educated, canal bank anglers while mercury advisories should be directed at canal bank anglers, who typically keep and consume their catch more than boat anglers, to those who live more than 30 miles from the area, and all anglers under the age of 48.
20
Hendrickson, Jamie Willis. "Structural Characterization of Parvalbumin from an Antarctic Notothenioid Fish Species". Fogler Library, University of Maine, 2005. http://www.library.umaine.edu/theses/pdf/HendricksonJW2005.pdf.
Testo completo
21
Parkyn, Gary. "Cloning and characterisation of angiotensin receptors in species of fish". Thesis, University of Exeter, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312337.
Testo completo
22
Costa, Graca Maria Pereira da. "Liver coccidiosis in some marine fish species from Scottish waters". Thesis, University of Aberdeen, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317711.
Testo completoAbstract (sommario):
The Coccidia Goussia clupearum (Thelohan, 1894) Labbe, 1896 was found infecting the liver of four different fish species from Scottish water; herring Clupea harengus, mackerel Scomber scombrus, Norway pout Trisophterus esmarkii and poorcod Trisopterus minutus. Sprat Sprattus sprattus was not infected. The stages of development corresponding to gamogony and sporogony of this parasite are described by light and electron microscopy on livers of naturally infected fish. Macroscopical lesions due to coccidiosis were not found. A condition named as 'red liver' was found in some infected Norway pout. However, there is no evidence of its being a symptom of liver coccidiosis alone but may be related to environmental factors. Histopathological studies of infected livers revealed an effective host reaction in herring, mackerel and Norway pout with engulfing of parasitic stages by host phagocytes, lymphocytes and eosinophils. Occurrence of 'yellow bodies' was also sometimes observed in infected livers of herring and mackerel. Prevalence and intensity of Goussia clupearum infections was followed during the period from October '88 to January '91. There is evidence of a significant relationship between prevalence and season of the year and of a higher prevalence in adult fish compared with juveniles, although the difference was not statistically significant. No clear indication of a statistically significant decrease in condition factor with increasing intensity of liver coccidiosis was found. Experimental infections of uninfected herring with oocysts of G. clupearum collected from infected mackerel were unsuccessful. It is suspected that the life cycle of this coccidian involves euphausiids as intermediate hosts. This conclusion was drawn after studies of the feeding habits of the fish species examined during this work and their relative prevalences of G. clupearum.
23
White, D. J. "The CatchMeter : application of computer vision for fish species recognition". Thesis, University of Aberdeen, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.445154.
Testo completoAbstract (sommario):
This thesis describes trials of a computer vision machine (The CatchMeter) for identifying and measuring different species of fish. The fish are transported along a conveyor underneath a digital camera. Image processing algorithms determine the orientation of the fish utilising a moment-invariant method, identify whether the fish is a flatfish or roundfish with 100% accuracy, and measure the length with a standard deviation of 1.2mm and species with up to 99.8% sorting reliability for sixteen species of fish. The machine can theoretically process up to 30 000 fish per hour using a single conveyor based system. The length measurement algorithms are then further developed so that fish may move along an opaque conveyor belt, through the system and be presented in any position or orientation, against a relatively complex background. By this method the minimum length of fish that can be measured is 50mm and since images can be stitched together the upper limit is >1.5m. The length of fish is measured with an average error of ± 3%. Two methods of object recognition by colour are compared and are applied to fish species identification. The colour histogram method and generates variables for subsequent analysis. The grid method generates a grid on the object and uses the average RGB values in the grid elements as a set of variables for the object. It was found that increasing the number of grid elements and the number of colour cubes (bins) increased sorting accuracy. A classification accuracy of 82.9% for nine species of fish was achieved using colour histograms and 98% using average colours. Furthermore, simple shape descriptors were added to the analysis and this improved the sorting accuracy to 98.5% for the colour histogram method and 99.8% for the grid with average colours method for seven species of fish. Fish species determination using black and white images and by feature extraction using edge detection methods are described with sorting accuracies of up to 95.3% and 97.7% respectively. A machine that was constructed based on the methods in this thesis is currently installed on one of the most advanced marine research vessels in the world, the Norwegian G.O. Sars.
24
Torres, Lisette E. "Variation Among Fish Species in the Stoichiometry of Nutrient Excretion". Miami University / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=miami1123178303.
Testo completo
25
Laughlin, Thomas Fain. "Hypervariable DNA markers and population structure in three fish species". Diss., This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-06062008-171854/.
Testo completo
26
Liyanapatirana, Chamindu. "Microfluidic analysis of free amino acids from different fish species". Master's thesis, Mississippi State : Mississippi State University, 2008. http://library.msstate.edu/etd/show.asp?etd=etd-02032008-193849.
Testo completo
27
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.
Testo completo
28
Abban, Edward Kofi. "Taxonomy and biochemical genetics of some African freshwater fish species". Thesis, Swansea University, 1988. https://cronfa.swan.ac.uk/Record/cronfa43062.
Testo completo
29
Kassler, T. W. "Genetic assessment of two stizostedion species and their hybrid in the Ohio River, final report". [Champaign, Ill.] : Illinois Natural History Survey, Center for Aquatic Ecology, 2000. http://hdl.handle.net/2142/10599.
Testo completoAbstract (sommario):
Includes bibliographical references."Submitted to Ohio Division of Wildlife." "The first objective was to determine the accuracy of field identification of individual fish to species and to assess the extent of hybridization between walleye and sauger ... The second objective was to assess genetic variation in both species ... " -- p.3. Also available in print.
30
Sapp, Shawn A. "Population trends of major near-shore fish species in Indiana waters of Lake Michigan". Virtual Press, 1999. http://liblink.bsu.edu/uhtbin/catkey/1125023.
Testo completoAbstract (sommario):
The purpose of this research was to determine population trends of major nearshore fish species in Indiana waters of Lake Michigan from 1984 to 1998 to gain insight into species dynamics. Index trawl samples were collected twice monthly from June through August at three locations. Trends of catch-per-unit-effort (CPUE) were investigated for the most abundant species: yellow perch (Perca flavescens), alewife (Alosa pseudoharengus), spottail shiner (Notropis hudsonius), rainbow smelt (Osmerus mord iz), and bloater (Coregonus hoyi). Trawl catch of yellow perch, alewife, and spottail shiners at sites M, K, and G were strongly correlated suggesting similar fluctuations. Young-of-the-year trawl catch revealed that insight to population dynamics of species was not always reliable. Trawl CPUE of > age 1 fish provided insight to dynamics of the major species at all sample locations with strong trend similarities between sites. No strong major species interactions were found using simple linear correlations.Department of Biology
31
Zhang, Ziyang. "Studies on otolith growth increments in Tilapia species". Thesis, Bangor University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.291686.
Testo completo
32
Duarte, Gonçalo Filipe Fernandes. "Ghost of diadromous fish past: streamlining research on diadromous fish species using historical data at european scale". Doctoral thesis, ISA/UL, 2019. http://hdl.handle.net/10400.5/18329.
Testo completoAbstract (sommario):
Doutoramento em Restauro e Gestão Fluviais - Instituto Superior de Agronomia / Faculdade de Arquitetura / Instituto Superior TécnicoThe decline of diadromous fish species has been occurring at least since the beginning of the 20th century. In this thesis, multiple European databases on the historical distribution of diadromous fish were consulted and, acknowledging the lack of data for Portugal, the first database of Portuguese historical data for freshwater fish was created. The existence of multiple databases with distinct geographical coverage and data at different spatial scales lead to the development of an historical data framework able to deal with the limitations of historical data. Its output is a reliable and geographically broad dataset of diadromous species occurrence at the beginning of the 20th century at three spatial scales: basin, sub-basin and segment. Also, a software was developed to facilitate the acquisition of environmental and riverscape variables that can be linked with the data at the three scales. Longitudinal connectivity impairment, climate change and land use alterations are some of the most significant threats to diadromous fish species. The influence of these threats was studied performing a spatial and temporal analysis of the longitudinal connectivity impairment by large dams and, modelling the distribution of diadromous fish at the beginning of the 20th century using climate and land use variables. The longitudinal connectivity impairment of the European freshwater networks became widespread in the second half of the 20th century, and is currently more impactful for populations from basins in southern Europe. The distribution of diadromous fish species is mainly affected by climate, though the effects of land use close to river mouths may be relevant since these are critical passage and entry points for the remaining network. The framework and the software developed were key to achieve the scientific knowledge presented, and more importantly, these can be established as the structural basis for future research on diadromous fish species
N/A
33
Syaifullah, of Western Sydney Hawkesbury University e Faculty of Science and Technology. "Genetic variation and population structure within the Gudgeon genus Hypseleotris (Pisces-Eleotridae) in Southeastern Australia". THESIS_FST_XXX_Syaifullah_X.xml, 1999. http://handle.uws.edu.au:8081/1959.7/231.
Testo completoAbstract (sommario):
This study investigated the causes of high level of intra-and inter-population variation known to occur in the morphology of fish in the genus Hypseleotris Eleotride in southern Australia, particularly within the Murray-Darling river system. The three major objectives of the study were, identify the number and distribution of species,determine the genetic structure of the populations and analyse relationships between species and consider the process of speciation in this species complex. The investigation of morphological variation in Hypseleotris confirmed the presence of two well known species i.e. H. compressa and H. galli, in the coastal rivers and also of the inland species H. klunzingeri. Populations of Hypseleotris klunzigeri sensu lato in inland river were found to be very highly variable and analysis using discriminant functions and principle component analysis showed the widespread presence of three forms (A, B1 and B2). The analysis was confused by the presence of north/south clines and upstream/downstream variation in characteristic in each form. After these factors were removed, there was still a great deal of variation in each population. The presence of hybrids between each pair of inland species, identified by both morphological and genetic data, further confused the analysis and makes identification of all specimens to species in the field difficult. Examination of type material of H. Klunzingeri showed that this belonged to form B2. The other forms can be related to the undescribed species, Midgley's carp gudgeon and Lake's carp gudgeon. Keys to the species in the complex in southeastern Australia are given. The morphological and genetic data show that H. compressa and H. klunzingeri are sister species, primarily separated by the eastern uplands. Similarly, the coastal species, H. galli is related to form B1 and more distantly, to form A. Possible scenarios for the complex are given.Doctor of Philosophy (PhD)
34
Alexander, Gavin D. "Foraging ecology of goosander (Mergus merganser) and red-breasted merganser (M. serrator) ducklings in north east Scotland". Thesis, University of Aberdeen, 1995. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU083108.
Testo completoAbstract (sommario):
Fish populations were sampled by electrofishing at a variety of sites on the Rivers N. Esk (1992-3) and Dee (1993-4) for comparison with sawbill duckling diets from the same rivers. Sampling methods are described and discussed in relation to other methods and in terms of possible biases. Within electrofished samples species distribution were similar on the two rivers, but more fish were caught per unit effort on the N. Esk. Catch results are described in terms of fish numbers and catch weights of each species from different sections of river and from different sampling times over the summers. Special attention is paid to the distribution and size frequency of salmon, because of their importance in the fish communities of the two rivers and as food for sawbill ducklings. The diets of goosander and merganser ducklings on the study rivers are quantified in terms of species of prey in the diet, size/age classes of fish and relative proportions of these species and classes. Estimates of diet are made from the stomach contents of samples of ducklings. Species composition of the diets are then related to the distribution of fish in those parts of the rivers in which the ducklings forage. Sizes of fish in the diets are then related to the sizes of fish in the duckling foraging areas, taking into account the changes in fish size with location and overtime, and the size (and approximate age) of ducklings. For comparison with diets, fish length data from electrofished samples was interpolated by regression between pairs of consecutive samples and adjacent river sections. This provided expected mean river fish lengths for the dates and locations at which broods were sampled.
35
O'Sullivan, Martha. "Population structure of demersal fish species in the north eastern Atlantic". Thesis, Available from the University of Aberdeen Library and Historic Collections Digital Resources. Restricted: no access until Dec. 31, 2010. Online version available for University members only until June 2, 2011, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=26063.
Testo completo
36
Khem, Sarim. "Development of model fermented fish sausage from New Zealand marine species". Click here to access this resource online, 2009. http://hdl.handle.net/10292/807.
Testo completoAbstract (sommario):
Three New Zealand marine species, hoki (Macruronus novaezealandiae), kahawai (Arripis trutta) and trevally (Pseudocaranx dentex) were used to develop model fermented fish sausage. The formulation comprised fish mince, carbohydrate, minced garlic and salt in a mass ratio of 1 (fish): 0.15: 0.05: 0.03, respectively. The carbohydrate source was cooked rice or glucose. (Endogenous lactic acid bacteria (LAB) failed to ferment rice). Folate was also added to the mixture as a factor. The mixtures were extruded into 50 mL plastic syringes, where the needle end of the barrel had been excised by lathe. The lubricated barrel was overfilled to 60 mL, capped with a layer of ParafilmTM and aluminium foil, sealed tightly by rubber band and incubated at 30°C. Over time the piston was progressively advanced to yield samples for microbiological, physical, and chemical analysis. Over 96 hours an increase in the LAB count was observed with a concomitant decrease in pH. After fermentation was complete, the samples contained around 8.77 log cfu LAB g-1 with the pH range from 4.38 to 5.08. The microbiological and pH behaviour of each species varied between preparations. Hardness, adhesiveness, springiness and cohesiveness of the treatments increased with fermentation, except for hoki. The treatments showed different colour characteristics with fermentation. The light reflectance (L* values) of the trevally and kahawai treatments increased, while the a* (redness) and b* (yellowness) values decreased. Hoki exhibited smaller colour changes except for yellowness, which increased markedly. Proteolysis, measured colorimetrically by soluble peptide bonds, was greatest for trevally. Lipid oxidation, measured by the thiobarbituric acid method, was least for hoki, notably the species with the lowest fat content. Biogenic amines, which are a general quality indicator of fermented products, increased during fermentation. The trevally treatment generated the highest concentration of amines, but these values were lower than those reported for fermented fish sausage in Southeast Asia. Notably there were no important difference between folate treatments and those without folate. The results point to commercial opportunities and further research with New Zealand marine species, especially trevally. To improve the product quality and to show geographical exclusivity, further research could be done by using starter culture, and a New Zealand staple carbohydrate source such as kumara and potato, and spices and herbs which are commonly used in New Zealand, such as rosemary, thyme and sage or specific to New Zealand, such as horopito. In addition, sensory studies should also be performed before the products could be tested in the market.
37
Shank, Isabelle. "Behavioural Syndromes: Implications for Electrocommunication in a Weakly Electric Fish Species". Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/24169.
Testo completoAbstract (sommario):
Behavioural syndromes, defined as suites of correlated behaviours across different contexts, are used to characterize individual variability in behaviours. Males of the weakly electric fish species, Apteronotus leptorhynchus, produce electro-communication signals called chirps. Chirps are thought to be involved in agonistic signalling, as their relative incidence increases during agonistic conspecific interactions. However, high levels of individual variability in aggression obscure the role of chirps in mediating aggression. Here, I tested the presence of an aggression-boldness behavioural syndrome, and then considered the implications such a syndrome would have on chirping behaviours. Behavioural tests in anti-predation, object novelty, feeding, conspecific intrusion and novel environment exploration contexts revealed a syndrome involving only object novelty and feeding. We found no correlation between chirping behaviour and the assessed behaviours. Our results demonstrate that chirps represent a more complex communication system than previously suggested.
38
Sarkardei, Samiramis. "Mechanisms of lipid oxidation and safety assessment in underutilised fish species". Thesis, University of Surrey, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.418255.
Testo completo
39
Bracewell, Philip John. "The effects of electric fishing on some freshwater cyprinid fish species". Thesis, University of Hull, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327287.
Testo completo
40
Strachan, N. J. C. "Automatic fish species grading using image processing and pattern recognition techniques". Thesis, University of Aberdeen, 1990. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU546342.
Testo completoAbstract (sommario):
Size and species grading of fish (eg on board a fishing vessel) might in future be done entirely automatically using image analysis and pattern recognition techniques. Three methods of discriminating between pictures of seven different species of fish have been compared: using invariant moments, optimisation of the mismatch, and shape descriptors. A novel method of obtaining the moments of a polygon is described. It was found that the shape descriptors gave the best results with a sorting reliability of 90&'37. Different methods of producing symmetry lines from the shape of fish have been studied in order to describe fish bending and deformations. The simple thinning algorithm was found to work best to provide a reference axis. This axis was then used as a basis for constructing a deformation independent position reference system. Using this reference system position specific colour measurements of fish could be taken. For this to be done the video digitising system was firstly calibrated in the CIELUV colour space using the Macbeth colour chart. Colour and shape measurements were then made on 18 species of demersal and 5 species of pelagic fish. The simple shape measurements of length/width and front area/back area ratios were used to do some introductory separation of the fish. Then the variables produced by the shape descriptors and colour measurements were analysed by discriminant analysis. It was found that all of the demersal fish were sorted correctly (sorting reliability of 100&'37) and all of the pelagic fish were sorted correctly except one (sorting reliability of 98&'37). A prototype machine is now being constructed based on the methods described in this work.
41
Dunn, Matthew Richard. "The exploitation of selected non-quota species in the English Channel". Thesis, University of Portsmouth, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301983.
Testo completo
42
Pen, Luke Jerome. "The biology of four species of native and two species of introduced fish in south-western Australia". Thesis, Pen, Luke Jerome (1990) The biology of four species of native and two species of introduced fish in south-western Australia. PhD thesis, Murdoch University, 1990. https://researchrepository.murdoch.edu.au/id/eprint/52017/.
Testo completoAbstract (sommario):
A seine net (3 mm mesh), and where necessary other methods, were used to collect three native species (Galaxias occidental is, Bostockia porosa and Edelia vittata) and two introduced species (Gambusia affinis and Perea fluviatilis) at regular intervals from the southern branch of the Collie River. The same net was used to sample the native species Galaxiella munda from a tributary of the Warren River 120 km further south in Western Australia. Annuli on otoliths and the seasonal trends shown by gonadal development, including changes in oocyte diameter, were used to determine the age and the duration and peak time of spawning of each of the four native species.
Spawning of all four native species, which follows a movement into either tributary creeks or flood waters, takes place between mid-winter and mid-spring, with the peak time of spawning differing slightly amongst species. While sexual maturity is reached by G. occidentals, E. vittata and G. munda at the end of the first year of life, it is not attained by B. porosa until the end of the second year of life. Each species can live for five or six years, except G. munda which dies before it reaches two years of age. The breeding of G. afTinis occurs in the shallows between mid-spring and late summer, while that of P. fluviatilis takes place in deeper water in the spring.
Amongst the native species, G. occidentals and B. porosa spawn only once in a breeding season, whereas E. vittata and G. munda are multiple spawners, producing clutches of eggs at intervals throughout the spawning period. The relationships between the age and size at first maturity and the growth rate and spawning mode of these four species are discussed. The influence of growth of the females of G. affinis during the spring and summer on the number of live young they produce is determined.
All of the above native and introduced species are carnivorous. At most times of the year, the diets of G. occidentals and 0+ P. fluviatilis, which were characterised by insects from the water surface and copepods from the plankton respectively, showed little overlap with those of other species. Although B. porosa and E. vittata both fed predominantly on benthic invertebrates, the former species ingested a greater amount of larger prey and fed at night rather than during the day. The diets of G. affinis varied considerably at different times and in different locations, indicating that this species was particularly opportunistic and could focus on prey which were abundant.
Comparisons are made between the biology of native fish in the highly seasonal environment of south-western Australia and those of the same and other families in eastern Australia and New Zealand.
43
Townhill, Bryony Lindsey. "Marine species and climate change : using modelling techniques to investigate effects on species distributions". Thesis, University of Exeter, 2016. http://hdl.handle.net/10871/25283.
Testo completoAbstract (sommario):
Anthropogenic climate change is one of the main challenges affecting the globe, with particular implications for the oceans. Marine climate change research has moved forward rapidly in recent years, and a range of physical model outputs are available that can be used by ecologists to help predict how species might be affected into the future. Policy makers require a level of understanding of how certain species and their ranges might change so that they can respond with sustainable management actions. This thesis aims to make use of a number of modelling techniques to explore implications of past and future conditions for marine species, and to appraise those tools that can be used under differing circumstances. Policy questions are answered relating to changes in the abundance and distribution of marine species. The links between historical climatic conditions and Barents Sea cod abundance are explored using Generalised Additive Models using data collected in the middle of the 20th century. This valuable historical data indicated that cod have temperature preferences and expand and shift their distributions based on environmental conditions. A simpler modelling technique is used to examine how oxygen conditions have changed in recent decades in the North Sea, how they might change in the future, and what implications this has for commercial fish species. The models show that oxygen conditions have improved recently and that they will not decrease to levels that result in large negative effects in the coming century. Species distribution modelling using a combination of global and downscaled model outputs shows that the UK will become more suitable for some non-native and harmful algal species in the 21st century, and less suitable for others. The model outputs contribute to the understanding of climate change effects and development of management tools to ensure the resilience of marine ecosystems into the future.
44
Go, Jeffrey. "Megalocytiviruses of freshwater ornamental fish and pathogenicity in marine and euryhaline species". Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/14118.
Testo completoAbstract (sommario):
Megalocytiviruses affect a broad range of fish species and have caused widespread mortality in aquaculture throughout Asia. The first confirmed report involved mass mortality in red sea bream cultured off Shikoku Island, Japan in 1990. Ornamental fish exhibiting pathology consistent with Megalocytivirus infection have been reported from a range of countries, frequently in association with fish recently imported from south east Asia. Although the relationship between megalocytiviruses in ornamental fish and food fish remains unclear, a potential linkage between a Megalocytivirus from a disease outbreak in Murray cod, Maccullochella peelii, in Australia and those in ornamental fish imported from south east Asia had been demonstrated experimentally. However, no data existed on the strains of virus involved in the first reported cases of Megalocytivirus-like pathology in ornamental fish. Furthermore, the potential for spread from ornamental fish to food fish other than Murray cod was also unknown. This study aimed to characterise Megalocytivirus from archival ornamental fish tissues, and to determine the potential for spread of megalocytiviruses from freshwater ornamental fish to other species, including marine fish. In situ hybridisation (ISH) assays were developed to demonstrate megalocytiviral DNA in tissue sections. The presence of megalocytiviral DNA was confirmed in two archival ornamental fish from 1986 and 1988 which had Megalocytivirus-like pathology. Unlike all other reported cases of Megalocytivirus in ornamental fish, these cases did not involve the Infectious spleen and kidney necrosis (ISKNV)-like genotype. The sequence of the major capsid protein (MCP) and the adenosine triphosphatase (ATPase) genes from the viruses in the archival tissues had a high degree of identity to each other (96.7-100%) and to a turbot reddish body iridovirus (TRBIV)-like Megalocytivirus (96.6-99.9%), reported as a cause of mass mortality in barred knifejaw, Oplegnathus fasciatus, fingerlings in Taiwan. By contrast, MCP sequences of Megalocytivirus in ornamental fish samples from 2002-2010 had almost complete identity to each other (99.9-100%) and to ISKNV, and only 91.5-95.0% identity to the archival samples, providing further evidence that these megalocytiviruses were genetically distinct. Megalocytiviruses in ornamental fish cases during 1986-1993 were TRBIV-like whereas all cases from 1996 onwards were ISKNV-like. Evidence also indicated that a single ornamental fish could be concurrently infected with two different megalocytiviruses. The confirmation of Megalocytivirus infection in ornamental fish prior to 1990 resulted in a revision of the index case for confirmed Megalocytivirus in any fish species. The detection of a novel TRBIV-like strain of Megalocytivirus in ornamental fish raised the possibility that current polymerase chain reaction (PCR) assays may not detect this group of megalocytiviruses. Consequently, new conventional and real-time quantitative (q) PCR assays were developed to differentiate between megalocytiviruses from each of the three major Megalocytivirus genotypes. The discovery of a potential link between historical cases of Megalocytivirus infection and a recent disease outbreak in barred knifejaw, provided further impetus for investigation of the potential for spread of megalocytiviruses from freshwater ornamental fish to marine fish species. The susceptibility of Australian bass, Macquaria novemaculeata, an important euryhaline Australian native species, to a Megalocytivirus (DGIV-10) originating from a recently imported dwarf gourami, Trichogaster lalius, was tested. Australian bass were susceptible to lethal infection with this Megalocytivirus both by direct inoculation and by cohabitation, and transmitted Megalocytivirus to naïve Murray cod through cohabitation. Australian bass could therefore be used as a model to study vector-borne transmission of Megalocytivirus between freshwater and marine fish species. Silver sweep, Scorpis lineolata, an Australian native marine fish was shown to be highly susceptible to DGIV-10 both by direct inoculation and cohabitation, and is the first Australian marine fish with demonstrated susceptibility to a Megalocytivirus originating from ornamental fish. Transmission of DGIV-10 from freshwater Murray cod to euryhaline Australian bass and then to marine silver sweep was demonstrated using cohabitation. Transmission of DGIV-10 from marine silver sweep to euryhaline Australian bass and then to Murray cod was also demonstrated. In summary, megalocytiviruses originating from the freshwater ornamental fish trade were demonstrated to be a potential biosecurity risk not only to Australian native freshwater species, but also to euryhaline and marine species and therefore to marine aquaculture, and recommendations for further research are presented.
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Buckwalter, Joseph Daniel. "Temporal trends in stream-fish distributions, and species traits as invasiveness drivers in New River (USA) tributaries". Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/64773.
Testo completoAbstract (sommario):
Biological invasions represent both an urgent conservation problem and an opportunity to advance ecological theory. Development of pertinent research questions and proactive management strategies require knowledge of which introduced species are present and of spatiotemporal trends in the distribution of natives and invaders. In Chapter 2 we developed a quantitative framework to identify spreaders and decliners and estimate invasion chronologies based on a historical fish presence data set for upper and middle New River (UMNR) tributaries. Our framework accounts for spatiotemporal variability in sampling effort by aggregating presences by watershed and expressing range size as a function of the number of watersheds sampled per time period. The majority (55%) of fish species present in the study area were introduced, 51% of which were spreaders. Most spreaders (84%) appeared to be spreading exponentially. The rate of new introductions detected in the study area has slowed since the mid-20th century. Two natives, the mound-spawning bluehead chub Nocomis leptocephalus and its strong nest associate (reproductive mutualist), mountain redbelly dace Chrosomus oreas, were among the most rapid spreaders. Four natives showed evidence of decline. Our framework leverages historical presence data to reconstruct temporal trends in species distributions. It sets the stage for further study of factors driving stream fish invasions and declines in the Appalachian region, and is transferable to diverse taxonomic groups and geographic regions.
Species traits and human activities mediating stream-fish invasions remain poorly understood. In Chapter 3 we modeled the contribution of species traits to invasion success of UMNR tributary fishes during the colonization and spread stages. Biological traits accurately explained colonization and spread success, whereas ecological traits resulted in less accurate models. Colonization success was positively related to time since introduction, benthic feeding, an equilibrium life history, and nest spawning. Successful spread was positively related to winter air temperature in the native range and an equilibrium life history. Variables estimating human use and propagule pressure were non-informative. Traits that influenced invasion success were consistent with the hypothesis that human land-use practices have increased the invasibility of highland watersheds by creating novel conditions suited to lowland and equilibrium invaders.Master of Science
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Hupé, Ginette Jessica. "Electrocommunication in a Species of Weakly Electric Fish Apteronotus Leptorhynchus: Signal Patterning and Behaviour". Thesis, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/20675.
Testo completoAbstract (sommario):
Weakly electric fish produce and detect electric fields and use their electrosensory modality in a number of behaviours including navigation and communication. They can modulate their electric discharge in frequency and amplitude to produce electrocommunication signals in variable patterns during social interactions. In one model neuroethological species, Apteronotus leptorhynchus, the most commonly produced communication signal is the ‘small chirp’ – a brief 10-30ms modulation. Individuals tend to produce these signals at high rates during agonistic interactions. In this thesis I will explore the social value of chirps, and to a lesser extent other communication behaviours, in A. leptorhynchus using a variety of experimental designs involving different staged social contexts. I use time series analysis methods to explore the patterns of chirps produced and accompanying aggressive behaviours.
I first characterize electrocommunication and chirping in pairs of free swimming fish and correlate signal production with aggressive displays. Bursts of echoed, or reciprocated, chirps tend to be produced in the intervals separating aggressive attacks. Behavioural analysis shows that fish respond to conspecific chirps with echoed chirps and decreased aggression in social contexts outside the range in which previous modelling and electrophysiological data predicted that chirps could be encoded effectively.
I then characterize the chirping and aggressive responses to playbacks simulating intruders with different chirping styles to test whether alternative chirp patterns differentially influence conspecific behaviour. In response to simulated intruders producing chirps that echo the real fish’s chirps with a short latency, less aggressive fish tend to produce more of their chirps in bursts than more aggressive fish. For randomly chirping intruders, the response of fish depends on the rate of chirps delivered. Fish respond less aggressively, with fewer chirps, and echo the stimulus chirps at a higher rate when high rates of random chirps are delivered than when responding to simulated intruders with low rates of randomly delivered chirps. Further, across all playback scenarios, fish that produce chirps in response to the playbacks are more aggressive than those that do not chirp. Finally, to better understand the electrosensory inputs during these interactions, I characterize changes in the electric image received by a restrained fish during movements of a free-swimming conspecific and correlate these with chirp production. When one fish is restrained, bursts of chirps tend to be associated with approach behaviours. Communication signals often function to promote individual assessment of potential rivals during agonistic encounters and bursty, antiphonal chirp exchanges may facilitate these assessments and deter potentially costly physical escalations.
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Kuta, Kevin G. "The Effect of Demersal Reef Fish on Two Species of Gorgonian Coral". NSUWorks, 1992. http://nsuworks.nova.edu/occ_stuetd/356.
Testo completoAbstract (sommario):
The effect of demersal reef fish on the gorgonians Pterogorgia anceps and Plexaurella grisea was determined under controlled conditions. Demersal reef fish cause significant changes in Pterogorgia anceps zooxanthellae concentration (cells cm-3), bulk density (g cm-3), and spicule concentration (g cm-3). Growth rates as measured by changes in planar area (cm2) are not significantly affected. No significant differences were found among any of the parameters measured for Plexaurella grisea; however, trends in the data were similar to those of P. anceps.
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au, bwise@fish wa gov, e Brent Stephen Wise. "Age composition and growth rates of selected fish species in Western Australia". Murdoch University, 2005. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20061123.120638.
Testo completoAbstract (sommario):
Growth typically varies considerably amongst the individuals in a population and between individuals in different populations of the same species, especially when those populations are found in environments in which the characteristics differ markedly. Although the annuli in hard structures are often used to age fish, such growth zones are not always clearly defined in these structures. Thus, in these cases, it is necessary to use alternative methods for ageing, such as analysis of modal progressions in length-frequency data. However, these types of techniques can usually only identify distinct size classes that correspond to an age class. They thus only enable an individual fish to be aged when it is a member of a discrete size cohort. Such a situation generally only applies to the younger age classes. This thesis reports the results of studies on a species that can be aged using the annuli in one of its hard parts (asteriscus otoliths), i.e. Cnidoglanis macrocephalus, and four species (Amniataba caudavitatta, Apogon rueppellii, Pseudogobius olorum and Favionigobius lateralis) for which it was necessary to use a method such as length-frequency analysis for ageing.
Cnidoglanis macrocephalus is an important recreational and commercial species caught in coastal marine and estuarine environments in south-western Australia. However, all previous detailed studies on the age and growth on this species have focused on estuarine populations. This thesis reports the results of a study of the biology of C. macrocephalus in Princess Royal Harbour, a marine embayment on the south coast of Western Australia. Samples of C. macrocephalus were collected from amongst the macroalgae that were removed from this highly eutrophic embayment by mechanical harvesters. Analysis of the reproductive and size composition data derived from these catches showed that spawning occurs between October and December and that fecundity ranged from 75 in a 384 mm fish to 465 in a 443 mm fish. Small fish (<200 mm) were rarely caught, reflecting the fact that the young of this species are difficult to capture.
Analysis of the trends exhibited by the marginal increments on otoliths showed that the number of annuli on this hard structure could be used to age C. macrocephalus. The samples of C. macrocephalus collected from Princess Royal Harbour contained female and male fish that had lived for up to 10 and 9 years in age and reached maximum lengths and weights of 523 mm and 745.3 g and 557 mm and 735.8 g, respectively. To overcome the paucity of small fish, von Bertalanffy growth curves were constructed using back-calculated lengths and employing the scale proportional hypothesis and body proportional hypothesis (see Francis 1990). The growth rates of females and males were slower than those in a nearby seasonally closed estuary (Wilson Inlet) and in a permanently open estuary on the lower west coast of Australia (Swan River Estuary). Yield per recruit analyses were conducted in order to ascertain what minimum legal lengths were appropriate for the capture of C. macrocephalus in Princess Royal Harbour, the Swan River Estuary and Wilson Inlet in order to sustain the stocks in those water bodies.
The age and growth of Amniataba caudavittata and Apogon rueppellii in the Swan River Estuary were determined by analysing the trends exhibited by modes in sequential monthly length-frequency data. This was achieved by employing MULTIFAN, which constrained the means of the lengths of the cohorts in successive monthly samples to a seasonal form of the von Bertalanffy growth curve. The resulting growth parameters derived by MULTIFAN were similar to those derived from the growth curves fitted to the means of the cohorts determined independently for each monthly sample by MIX.
The discreteness of the distributions and modes of size classes in length-frequency data for A. caudavittata and A. rueppellii enabled sound growth curves to be constructed for both of these species. The growth curves of these two sexes of both species were significantly different, with K being lower and L being higher for females. The trends exhibited by these growth curves emphasised that the growth of both species is highly seasonal, with little or no increase in length occurring during the cooler part of the year. The seasonal von Bertalanffy growth equations implied that negative growth occurred in winter, but this is an artefact produced by size-related differences in offshore movements that occur at that time of the year.
The age and growth of two further species from the Swan River Estuary, Pseudogobius olorum and Favonigobius lateralis, were also studied. Since P. olorum and F. lateralis both spawn at different times of the year and these times (spring and autumn) are not regularly spaced during the year, they produce new 0+ recruits at two irregularly-spaced times of the year. Consequently, MUTLIFAN cannot be used to analyse the size-distribution data for these two gobiid species. Thus, MIX was used to identify the size classes present in sequential samples and to provide means for the length distributions of those size classes. von Bertalanffy growth equations were then fitted to the mean lengths at the inferred age of the males and females of each size class of each species. It was found appropriate to use the traditional von Bertalanffy growth curve for describing the growth of the product of the spring-spawning group of both species and a seasonal von Bertalanffy growth curve for that of the product of the autumn-spawning groups of both species.
The growth curves, when considered in conjunction with the trends exhibited by reproductive variables, demonstrate that female F. lateralis attains sexual maturity more rapidly and at a larger size than P. olorum. The majority of the female and male progeny of the summer and autumn-spawning groups of F. lateralis reach maturity when they are approximately 3½ and 8½ months old, respectively, compared with five and seven months old, respectively, for P. olorum.
Models, incorporating data on water temperature and salinity and the growth and reproduction characteristics of P. olorum and F. lateralis, were used to postulate how environmental factors might be regulating when these two gobiid species spawn. The results of these models support the conclusion that the bimodal timing of spawning of P. olorum in the upper estuary was regulated by water temperature, with spawning occurring between 20 and 25oC but inhibited by temperatures greater than 25oC. They also showed that, although water temperature also influenced the timing of spawning of F. lateralis in the lower estuary, the onset of spawning by this species only occurred when salinities had reached 300/00.
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Madden, Peter William. "Structural and Kinetic Characterization of Myoglobins from Eurythermal and Stenothermal Fish Species". Fogler Library, University of Maine, 2003. http://www.library.umaine.edu/theses/pdf/MaddenPW2003.pdf.
Testo completo
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Nunan, Gustavo W. "Composition, species distribution and zoogeographical affinities of the Brazilian reef-fish fauna". Thesis, University of Newcastle Upon Tyne, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386738.
Testo completo