Environmental factors affect fish distribution and fisher behavior. These factors are seldom included in stock assessment models, resulting in potentially inaccurate fish abundance estimates. This study determined the impact of these factors using the commercial catch rate of sauger (Sander canadensis) and walleye (Sander vitreus) in Lake Winnipeg by: (1) the use of satellite data to monitor turbidity and its impact on catch via simple linear regression and (2) the effect of environment on catch and effort using generalized linear models. No statistically significant relationship was found between catch and turbidity; a result which may be due to small sample sizes, the fish species' examined, and variable turbidity at depth. Decreased effort was correlated with harsh weather and decreased walleye catch. Increased walleye catch was correlated with low temperature and low Red River discharge. Increased sauger catch was correlated with high temperature, high cloud opacity, and average Red River discharge.

Environmental factors affect fish distribution and fisher behavior. These factors are seldom included in stock assessment models, resulting in potentially inaccurate fish abundance estimates. This study determined the impact of these factors using the commercial catch rate of sauger (Sander canadensis) and walleye (Sander vitreus) in Lake Winnipeg by: (1) the use of satellite data to monitor turbidity and its impact on catch via simple linear regression and (2) the effect of environment on catch and effort using generalized linear models. No statistically significant relationship was found between catch and turbidity; a result which may be due to small sample sizes, the fish species' examined, and variable turbidity at depth. Decreased effort was correlated with harsh weather and decreased walleye catch. Increased walleye catch was correlated with low temperature and low Red River discharge. Increased sauger catch was correlated with high temperature, high cloud opacity, and average Red River discharge.

This thesis had two overriding aims. The first was to describe the biology of Samson Fish Seriola hippos and therefore extend the knowledge and understanding of the genus Seriola. The second was to uses these data to develop strategies to better manage the fishery and, if appropriate, develop catch-and-release protocols for the S. hippos sportfishery. Trends exhibited by marginal increment analysis in the opaque zones of sectioned S. hippos otoliths, together with an otolith of a recaptured calcein injected fish, demonstrated that these opaque zones represent annual features. Thus, as with some other members of the genus, the number of opaque zones in sectioned otoliths of S. hippos are appropriate for determining age and growth parameters of this species. Seriola hippos displayed similar growth trajectories to other members of the genus. Early growth in S. hippos is rapid with this species reaching minimum legal length for retention (MML) of 600mm TL within the second year of life. After the first 5 years of life growth rates of each sex differ, with females growing faster and reaching a larger size at age than males. Thus, by 10, 15 and 20 years of age, the predicted fork lengths (and weights) for females were 1088 (17 kg), 1221 (24 kg) and 1311 mm (30 kg), respectively, compared with 1035 (15 kg), 1124 (19 kg) and 1167 mm (21 kg), respectively for males. Despite these differences, female and male S. hippos attained similar maximum age, i.e. 29 (1470 mm FL) and 28 years (1280 mm FL), respectively. The maximum age determined for S. hippos is greater than that recorded for any other Seriola spp. The largest female and male S. hippos recorded during this study were encountered during the tagging component and had fork lengths of 1600 mm and 1380 mm, respectively. Seriola hippos has a protracted spawning period, ca four months, which starts in late spring and continues through summer into early autumn during which time many individuals engage in large spawning aggregations on the lower west coast of Australia. The length at which 50 % of the females in the population reached maturity was 831 mm FL (888 mm TL) and approximately 4 years of age, whilst all females over 950 mm FL were mature. Whilst aggregated for spawning S. hippos ceases feeding, however, during the non-spawning period this species can best be described as an opportunistic carnivore which feeds on a variety of pelagic and demersal prey. This study has greatly increased our understanding of S. hippos movement on the west and south coasts of Australia and has documented, for the first time, the migratory behaviour of a carangid in these waters. Many S. hippos individuals undertake long distance migrations to join spawning aggregation sites near Rottnest Island. Individuals tagged at these aggregation sites where recaptured throughout this species distribution along the south coast of Australia, some after travelling distances of over 2400 km. Many S. hippos individuals displayed strong temporal and spatial spawning ground fidelity as numerous fish released at the spawning aggregations were recaptured at the exact same spawning site at similar times in subsequent years. Tagging data suggest that on the completion of spawning S. hippos individuals return to a resident location and remain in that general vicinity over the winter months. This study has developed a hypothesis describing larval dispersal associated with the S. hippos spawning behaviour exhibited near Rottnest Island. It is proposed that variations in the prevailing ocean currents, at this important spawning location throughout the protracted spawning period, leads to high intra and inter-annual variation in larval distribution and survival. The affect of this variation on the evolution of the spawning and migratory behaviour displayed by S. hippos is discussed. A recent increase in the popularity of S. hippos as a catch-and-release sportfish has led to concerns by some anglers about post release survival of this species, particularly due to the depth of capture. Short term mortality of S. hippos capture at the sportfishing sites was assessed by monitoring fish held within an enclosure near the site of capture for up to 31 hours post release. The total hooking mortality of S. hippos subjected to catch-and-release angling within the Rottnest Island sportfishery is approximately 8%. Most of this observed mortality is delayed and occurs sometime after release. Although best handling practises require ongoing development, the current level of mortality associated with this catch-and-release fishery is considered acceptable. Furthermore, this mortality is likely to have little effect on the S. hippos population due to the high abundance of this species and the fact that even the highest fishing effort yields a relatively low catch. Seriola hippos exhibits a typical teleost neuroendocrine stress response associated with catch-and-release. The physiological dysfunction associated with the stress of capture in this species does not appear to cause any post release mortality. Instead, most mortality was attributable to barotrauma, however, although mortality in S. hippos increases with capture depth, this species is much less susceptible to depth induced mortality than other commonly targeted species in which barotrauma has been observed. This study developed key handling protocols for fishers who catch-and-release S. hippos at the Rottnest Island aggregation sites. These protocols cover aspects of catch-and-release fishing such as hook type, water depth, time at surface, release method and shark predation. Almost all S. hippos observed during capture from deep water released large quantities of gas from the opercular region, particularly during the last 10 to 20 m before reaching the surface. This phenomenon has also been witnessed by divers and fishers to occur under natural conditions. Investigations into this release of gas revealed this physoclistous species to exhibit unique swim bladder characteristics. Seriola hippos possess a membranous tube that connects the posterior-dorsal surface of the swim bladder internally to a region under each operculum externally. This connection, termed the swim bladder vent, allows the escape of expanding swim bladder gases on rapid ascent. The presence of the swim bladder vent provides an explanation as to why the incidence of external barotrauma symptoms in S. hippos captured from the deepwater was low. The ability to expel excess swim bladder gases during rapid ascent whilst retaining full swim bladder function is likely to offer this semi-pelagic species considerable advantages when hunting prey, avoiding predators and engaging in spawning activities. Preliminary estimates of total mortality indicated that S. hippos is not currently subjected to a high level of fishing pressure. However, managers must remain mindful of the fact that the size at which females reach sexual maturity, i.e. 888 mm TL, is greater than the current minimum legal length, i.e. 600 mm, and thus fishers are currently allowed to harvest sexually immature fish. Furthermore, the effectiveness of future conservation measures must consider the large scale migration and spawning strategy undertaken by this species in order to ensure its protection. The collaborative research approach undertaken during this study demonstrated that a high level of community engagement produced a large amount of research interest, increased stakeholder satisfaction from project input, improved understanding of research outcomes, and increased research uptake, all of which has led to increased stewardship and conservation of the S. hippos fishery and fisheries resources in general. Indeed, projects of this nature would not be possible without this type of approach.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2004. / Härtill 4 uppsatser.

Licentiatavhandling (sammanfattning) Uppsala : Sveriges lantbruksuniversitet. / Härtill 3 uppsatser.

Thesis--Münster. / Vita. Includes bibliographical references (p. [187]-196).

Thesis--Münster. / Vita. Includes bibliographical references (p. [187]-196).

Environmental factors affect fish distribution and fisher behavior. These factors are seldom included in stock assessment models, resulting in potentially inaccurate fish abundance estimates. This study determined the impact of these factors using the commercial catch rate of sauger (Sander canadensis) and walleye (Sander vitreus) in Lake Winnipeg by: (1) the use of satellite data to monitor turbidity and its impact on catch via simple linear regression and (2) the effect of environment on catch and effort using generalized linear models. No statistically significant relationship was found between catch and turbidity; a result which may be due to small sample sizes, the fish species' examined, and variable turbidity at depth. Decreased effort was correlated with harsh weather and decreased walleye catch. Increased walleye catch was correlated with low temperature and low Red River discharge. Increased sauger catch was correlated with high temperature, high cloud opacity, and average Red River discharge. / October 2006

Organizations responsible for managing commercial fisheries conduct annual stock assessments to monitor stock and, in principle, reduce the risk of overexploitation. These are fundamental to setting the total allowable catch for the upcoming fishing year. While there have been many attempts to estimate uncertainty associated with certain components and estimates of stock assessments, to date there has been no systematic assessment of their forecasted predicted value. Using data from annual stock assessments from 65 commercial fisheries around the world, estimates were obtained of both predicted (from the previous year) and observed (in the current year) catch-at-age. When comparing observed (actual) and predicted catch-at-age for a given stock, estimates were obtained of the predictive power of next-season forecasts. Using other attributes of the fishery and the stock (biological (e.g. life history) and management (e.g. assessment model employed)), empirical models were constructed that attempt to determine variability in predictive power among stocks. It was observed that, on average, within-year predictive powers (age-series within time samples) were higher than year over year predictive powers (time-series within age samples). While focusing on time-series within age, it was observed that change over the period of record (in natural mortality rate, assessment model employed, etc.) reduced predictive power; while for age-series within time, it was shown that cumulative landings reduced predictive power. This study represents one of the first attempts to quantify systematically the predictive power of fisheries stock assessment models.

Submitted by MARCELO MARUCCI PEREIRA TANGERINA null (marcelomptang@hotmail.com) on 2016-07-09T22:03:34Z No. of bitstreams: 1 Tese ABNT Marcelo Tangerina Wagner Vilegas CD.pdf: 3984472 bytes, checksum: 993744f837a77327c951b1988896f63c (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-07-12T17:19:33Z (GMT) No. of bitstreams: 1 tangerina_mmp_dr_araiq.pdf: 3984472 bytes, checksum: 993744f837a77327c951b1988896f63c (MD5) / Made available in DSpace on 2016-07-12T17:19:33Z (GMT). No. of bitstreams: 1 tangerina_mmp_dr_araiq.pdf: 3984472 bytes, checksum: 993744f837a77327c951b1988896f63c (MD5) Previous issue date: 2016-06-27 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A fauna acompanhante da pesca do camarão inclui uma série de invertebrados marinhos que são descartados por não ter valor comercial. A fim de tentar acrescentar algum valor a este material, foi analisada a composição química da estrela-do-mar Luidia senegalensis coletada na costa brasileira como consequência da aplicação da pesca de arrasto. A fim de avaliar sua composição química, foi utilizada uma combinação de extração em fase sólida (SPE) seguida de cromatografia líquida de ultra eficiência acoplada a espectrômetro de massas equipado com fonte de ionização por eletrosptray e analisador ion-trap linear (UPLCESI- IT-MSn). Luidia senegalensis contém asterosaponinas, que são esteroides glicosilados sulfatados contendo cinco e seis unidades de açúcar, além de poliidroxiesteroides. Este estudo mostrou a presença de compostos importantes e potencialmente bioativos em invertebrados associados à fauna acompanhante da pesca do camarão, usando um método rápido e eficiente. Normalmente descartada, a fauna acompanhante contém muitos invertebrados que podem hospedar uma grande variedade de gêneros de bactérias, algumas das quais com potencial de produzir produtos naturais bioativos com aplicações biotecnológicas. Assim, para utilizar um material normalmente descartado, foi explorado o potencial biotecnológico de bactérias cultiváveis de duas espécies de invertebrados abundantes na fauna acompanhante, o gastrópode Olivancillaria urceus e a estrela-do-mar Luidia senegalensis. Uma amostra de sedimento da mesma área de coleta também foi investigado. Utilizando múltiplas abordagens de isolamento 134 isolados foram obtidos a partir dos invertebrados e do sedimento. Sequenciamento parcial da subunidade de rRNA (16S) revelou que os isolados pertenciam aos filos Proteobacteria, Firmicutes e Actinobacteria, distribuídos em 28 gêneros. Vários gêneros conhecidos pela sua capacidade de produzir produtos naturais bioativos (Micromonospora, Streptomyces, Serinicoccus e Verrucosispora) foram obtidos a partir das amostras estudadas. Para avaliar as bactérias isoladas quanto à sua capacidade para produzir metabólitos bioativos todas as cepas foram fermentadas e os extratos de fermentação analisados por LC-HRMS e testados em ensaio de atividade antimicrobiana. Quatro cepas apresentaram atividade antimicrobiana contra Staphylococcus aureus resistente à meticilina (MRSA) e Staphylococcus warneri. A produção de metabólitos secundários por bactérias isoladas da fauna acompanhante também foi avaliada por uma abordagem metabolômica utilizando LC-HRMS, onde foi avaliado como as diferenças na composição dos meios de cultura podem alterar a produção de substâncias. Utilizou-se a metabolômica como uma ferramenta para investigar a produção de abyssomicinas, um agente anticâncer, e outros metabólitos secundários em três cepas do actinomiceto raro Verrucosispora maris, isoladas a partir de uma amostra de sedimento e associadas à estrela-do-mar Luidia senegalensis de Ubatuba - SP, Brasil. Nove composições diferentes de meios de cultura foram avaliadas e verificou-se que, dentre todas as cepas, somente RKMT_111 foi capaz de produzir abyssomicinas. O estudo da composição do meio de cultura revelou que a produção de abyssomicinas só foi possível em BFM-11m. Embora as três cepas pertençam à mesma espécie e são provenientes da mesma localização, é notável que cada isolado apresentou diferente capacidade de produção de metabólitos secundários. Os produtos de fermentação de Erythrobacter vulgaris foram avaliados utilizando técnicas de HPLC preparativo, LC-HRMS e RMN. A cepa foi isolada pelo método dry-stamp de uma amostra de sedimento marinho da costa de Ubatuba-SP, Brasil. Depois de sequenciamento completo do rRNA (16S) e identificação, o isolado foi fermentado em larga escala, seu caldo de fermentação extraído por solvente e os compostos purificados por HPLCMS. Análise de LC-HRMS e RMN dos compostos isolados levou à identificação de dois novos derivados do ácido cólico, ácido 3-acetil-glicocólico e o ácido 3-acetilglicodesoxicólico. As substâncias obtidas podem ter sido produzidas por biotransformação do ácido glicocólico e ácido desoxicólico, respectivamente, já presentes no meio de cultivo. Este é o primeiro relato de tais compostos e também a primeira observação de uma acilação realizada por um isolado marinho de Erythrobacter vulgaris. / The by-catch fauna of the shrimp fishery includes a number of marine invertebrates that are discarded because they do not have commercial value. In order to try to add some value to these materials, we analyzed the chemical composition of the starfish Luidia senegalensis collected in the Brazilian coast as a consequence of the trawling fishery method. In order to access their chemical composition, we used a combination of solid phase extraction (SPE) followed by ultra performance liquid chromatography coupled to electrospray ionization ion trap tandem mass spectrometry (UPLC-ESI-IT-MSn). Luidia senegalensis contains asterosaponins, which are sulphated glycosilated steroids, containing five and six sugar moieties, in addition to polyhydroxysteroids. This study helped us to support the presence of important and potentially bioactive compounds in invertebrates associated to the by-catch fauna of the shrimp fishery, using a fast and efficient method. Typically discarded, by-catch contains many invertebrates that may host a great variety of bacterial genera, some of which may produce bioactive natural products with biotechnological applications. Therefore, to utilize by-catch that is usually discarded we explored the biotechnological potential of culturable bacteria of two abundant by-catch invertebrate species, the snail Olivancillaria urceus and the sea star Luidia senegalensis. Sediment from the collection area was also investigated. Utilizing multiple isolation approaches 134 isolates were obtained from the invertebrates and sediment. Small subunit rRNA (16S) gene sequencing revealed that the isolates belonged to Proteobacteria, Firmicutes and Actinobacteria phyla and were distributed among 28 genera. Several genera known for their capacity to produce bioactive natural products (Micromonospora, Streptomyces, Serinicoccus and Verrucosispora) were retrieved from the invertebrate samples. To query the bacterial isolates for their ability to produce bioactive metabolites all strains were fermented and fermentation extracts profiled by LC-HRMS and tested for antimicrobial activity. Four strains exhibited antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus warneri. The production of secondary metabolites was assessed using a LC-HRMS-based metabolomics approach, where it was evaluated how differences in media composition can alter the production of chemical compounds. We used metabolomics as a tool to investigate the production of abyssomicins, an anticancer agent, and other secondary metabolites in three strains of the rare actinomycete Verrucosispora maris, all marine isolates from a sediment sample and associated to a starfish from the species Luidia senegalensis of Ubatuba – SP, Brazil. Nine different media compositions were evaluated and it was found that, among all strains, only RKMT_111 was capable of producing abyssomicins. The media composition study revealed that the production of abyssomicins was only achievable in BFM-11m. Although the three strains belong to the same species and the same location, it is worthwhile noticing that each isolate showed different capability for production of secondary metabolites. The products of fermentation of Erythrobacter vulgaris were evaluated using preparative HPLC, LC-HRMS and NMR techniques. Bacterial strain was isolated by drystamp method from a marine sediment sample from the coast of Ubatuba-SP, Brazil. After fully 16S rDNA sequence and identification, the marine isolate was fermented in large-scale, extracted and the compounds purified through HPLC-MS. Analysis of LC-HRMS and NMR of the isolated compounds led to the identification of two new cholic acid derivatives, 3- acetyl-glycocholic acid and 3-acetyl-glycodeoxycholic acid. Both new compounds may have been produced by the biotransformation of glycocholic acid and deoxycholic acid, respectively, already present in the cultivation medium. This is the first report of such compounds and also the first time an acylation has been observed for an Erythrobacter vulgaris marine isolate. / FAPESP: 2011/23159-0