Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2018-05-22T13:24:04Z No. of bitstreams: 1 PDF - Gleydson Kleyton Moura Nery.pdf: 28016541 bytes, checksum: dee318975b7418cd78bfb23b8b8cb2ec (MD5) / Approved for entry into archive by Secta BC (secta.csu.bc@uepb.edu.br) on 2018-05-23T16:37:33Z (GMT) No. of bitstreams: 1 PDF - Gleydson Kleyton Moura Nery.pdf: 28016541 bytes, checksum: dee318975b7418cd78bfb23b8b8cb2ec (MD5) / Made available in DSpace on 2018-05-23T16:37:33Z (GMT). No. of bitstreams: 1 PDF - Gleydson Kleyton Moura Nery.pdf: 28016541 bytes, checksum: dee318975b7418cd78bfb23b8b8cb2ec (MD5) Previous issue date: 2017-07-04 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The present study aims to adapt and apply a Biotic Integrity Index (IBI) for reservoirs in the Paraíba River basin located without Brazilian semiarid, with the use of fish community sites as a subsidy. For that, 20 points were sampled in 5 reservoirs with four sample stations from July 2016 to March 2017. The IBI was obtained by elaboration and selection of metrics based on the community studied. The study was divided into two chapters. In the first one, the factors that explain the adaptive success of Oreochromis niloticus in the aquatic systems of the semiarid were oriented. It was found that the invasion ability of O. niloticus was associated with both environmental factors and biological interactions. However, there is a strong influence of environmental variables linked to these relationships, since a dissimilarity of systems regarding water quality and habitat structuring directly influence the structuring of the community in terms of composition as trophic relationships. In the second chapter, the biotic integrity index based on the fish community was proposed and applied as an environmental assessment tool for non - semiarid systems. The composition of the index was based on the metrics% native species,% endemic species,% invasive species, abundance of cichlids, abundance of species,% sp. piscivorous and% sp. intolerant An application of the index for the semiarid to the problem, the limnological state of the environment, such as total phosphorus (r² = -0.62, p <0.005), chlorophyll a (r² = -0.74, p < 05) and volume (r² = 0.33, p <0.005). The study points to a community of fish as a good indicator of environmental quality, since, during the studied period, it reduced the quality of the quality of the environment with the direct reflection in the fish community. / O presente estudo tem como objetivo adaptar e aplicar um Índice de Integridade Biótica (IBI), para reservatórios da bacia do rio Paraíba localizado no semiárido brasileiro, tendo como subsídio a utilização de atributos da comunidade de peixes. Para tanto, foram amostrados 20 pontos distribuídos em 5 reservatórios com quatros estações amostrais no período de julho/2016 a março/2017. O IBI foi obtido pela elaboração e seleção de métricas com base na comunidade estudada. O estudo foi dividido em dois capítulos. No primeiro, foram avaliados os fatores que explicam o sucesso adaptativo de Oreochromis niloticus nos sistemas aquáticos do semiárido. Constatou-se que a habilidade de invasão de O. niloticus foi associada tanto a fatores ambientais, quanto as interações biológicas. Contudo, há uma forte influência das variáveis ambientais atrelados a estas relações, uma vez que, a dissimilaridade dos sistemas quanto a qualidade de água (eutrofização) e estruturação do habitat influenciam diretamente na estruturação da comunidade quanto a composição e as relações tróficas. No segundo capítulo, foi proposto e aplicado o índice de integridade biótica com base na comunidade de peixes, como ferramenta de avaliação ambiental de sistemas no semiárido. A composição do índice se baseou nas métricas % espécies nativas, % espécies endêmicas, % espécies invasoras, abundância de ciclídios, abundância de characiformes, % sp. piscívoros e % sp. intolerantes. A aplicação do índice para o semiárido foi eficaz, apresentando correlações significativas com variáveis que descriminam o status limnológico do ambiente, tais como, fosforo total (r²= -0,62; p< 0,005), clorofila-a (r²= -0,74; p< 0,05) e volume (r²= 0,33; p< 0,005). O estudo aponta a comunidade de peixes como um bom indicador de qualidade ambiental, uma vez que, ao longo do período estudado houve redução da qualidade cênica do ambiente com reflexo direto na comunidade de peixes.

Climate changes alter species composition in both aquatic and terrestrial ecosystems. For establishment of species in a fish community, dispersal barriers, habitat structure and interactions between species act as a filter. The aim of this study was to examine changes in the fish community in Lake Tåkern, Sweden, by repeating a test-fishing in a lake 40 years after a previous test-fishing. Special interest was directed towards the possible establishment of bream (Abramis brama) and (Cyprinus carpio) which recently had been found in the lake. In addition, a decline of the low oxygen tolerant species crucian carp (Carassius carassius) and tench (Tinca tinca) was expected. Test-fishing was performed in June and August 2019 and combined with analyses of Environmental-DNA from samples in September 2019. A comparison with the average catch of 1978-1979 together showed that all cyprinid species had decreased in 2019. The hypoxic tolerant crucian carp decreased 16-fold in numbers, which was expected due to fewer events of cold winters and hypoxia. One bream was caught from the test-fishing and was also detected through eDNA-analysis. The ecological status of the fish community was classified as moderate but showed a high proportion of piscivore percids contra cyprinids, compared to six other shallow lakes in Sweden with similar characteristics. The high proportion of piscivore percids is probably contributing to the stability of the present clear-water state of the lake.

Despite the increases in the intensity and frequency of disturbances on coral reefs in the Red Sea over the past decade, patterns of variability in fish communities are still poorly understood. This study aims to contribute to a better understanding of how fish communities vary along multiple spatial scales (10-100’ of kilometers) and to provide a baseline for future comparisons, fundamental to assess responses to climate change and other disturbances. Coral reefs along the Saudi Arabian Red Sea coast were surveyed from 2017 to 2019. The reefs ranged from 28° N to 18 °N and were categorized according their geographical location and grouped within three regions, namely north (24-28.5°N; 12 reefs), central (20.4-22.3°N; 11 reefs), and south (18.5-21.2°N; 30 reefs). The quantification of spatial patterns was conducted based on both taxonomic- and trait-based approaches. Considering the dependence of fish communities on the benthic habitat the relationship between different attributes of the fish assemblages and coral cover was also investigated. A consistent pattern of separation between assemblages of the northern and central region from the ones in the south was observed in nearshore reefs but was not evident for offshore reefs. The southern region supported higher densities, biomass, and species richness than the other two regions. The analysis showed that transect and reef scales contributed to the greatest variation in fish communities, suggesting higher levels of variability within small spatial scales. Several parameters of the fish community (total species, total density, total biomass, total functional entities, functional richness, functional redundancy) were positively correlated to coral cover, particularly in the northern region. Responses were not consistent across the Red Sea basin, suggesting that management plans should be regionally based. This study can be helpful to design management strategies as it provides a current baseline from both taxonomic and trait perspectives for Red Sea reefs that can be used to evaluate future changes due to natural and human-based disturbances.

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Following the construction of the Pongolapoort Dam in 1974, the potential impacts on the lower Phongolo River and floodplain due to alterations in the natural flow regime have caused concerns. Fish communities and population structures are directly influenced by these alterations. The only protected section of the Phongolo River is a 15 km reach and its associated pans that flow through the Ndumo Game Reserve. Historic data shows that the community and population structure of the fish in the Phongolo Floodplain has changed as a result of irregular flood releases. The Ndumo Game Reserve plays an important role in the conservation of many ecologically and economically important species as the pans inside the reserve serve as a refuge area in which these species can breed to replenish the fish numbers in the Phongolo River. The fish diversity inside the Ndumo Game Reserve is also higher when compared to outside. During the high flow period fish move into the floodplain pans as a result of the higher water level. Oreochromis mossambicus, the most common species found in this area, utilize Nyamiti Pan for breeding but the health of this species is under pressure due to severe infestations of Lernaea cyprinacaea and nematode parasites. Lernaea cyprinacaea is a parasitic copepod associated with the introduced exotic fish species Cyprinus carpio which is found in large numbers in various pans inside Ndumo Game Reserve. The presence of this alien species in the refuge area raises concerns as it competes for the same resources as the economically important native fish species. Nyamiti Pan is largely populated by adult cichlid species between the ages of six and ten years old. The importance of flood releases which simulate natural flow regime is emphasised by the negative impacts irregular floods have on fish health, community and population structure. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

Following the construction of the Pongolapoort Dam in 1974, the potential impacts on the lower Phongolo River and floodplain due to alterations in the natural flow regime have caused concerns. Fish communities and population structures are directly influenced by these alterations. The only protected section of the Phongolo River is a 15 km reach and its associated pans that flow through the Ndumo Game Reserve. Historic data shows that the community and population structure of the fish in the Phongolo Floodplain has changed as a result of irregular flood releases. The Ndumo Game Reserve plays an important role in the conservation of many ecologically and economically important species as the pans inside the reserve serve as a refuge area in which these species can breed to replenish the fish numbers in the Phongolo River. The fish diversity inside the Ndumo Game Reserve is also higher when compared to outside. During the high flow period fish move into the floodplain pans as a result of the higher water level. Oreochromis mossambicus, the most common species found in this area, utilize Nyamiti Pan for breeding but the health of this species is under pressure due to severe infestations of Lernaea cyprinacaea and nematode parasites. Lernaea cyprinacaea is a parasitic copepod associated with the introduced exotic fish species Cyprinus carpio which is found in large numbers in various pans inside Ndumo Game Reserve. The presence of this alien species in the refuge area raises concerns as it competes for the same resources as the economically important native fish species. Nyamiti Pan is largely populated by adult cichlid species between the ages of six and ten years old. The importance of flood releases which simulate natural flow regime is emphasised by the negative impacts irregular floods have on fish health, community and population structure. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

Master of Science / Department of Biology / Craig Paukert / I evaluated sampling strategies and the effects of dike structure modifications in the lower Missouri River to better develop sampling and mitigation strategies to protect and enhance native river fishes. Sampling occurred in the lower 1,212 km of the Missouri River during October-June (coldwater season) and June-October (warmwater season) with stationary gill nets (GN), drifted trammel nets (TN), towed otter trawls (OT), and mini fyke nets (MF) from 2003-2006. We compared probabilities of detection (p), variability (coefficient of variation; CV) in catch per unit effort, and lengths for 25 species. Over 80% of adult large-bodied fishes were collected in GN during coldwater, >90% of chub spp. (Macrhybopsis) were collected in OT, and >90% of nine small-bodied and juvenile fishes were collected in MF. Trammel nets never had the highest p during coldwater, but had the highest or equally high p for 85% of adult large-bodied fishes during warmwater. Mean CV was lowest with GN for adult large-bodied fishes; chub spp. had the lowest CV in OT. Mean lengths were typically greater in GN and TN. Large river monitoring programs might best achieve the highest p, lowest variability, and widest size range of fishes by employing GN and OT during coldwater and TN, OT, and MF during warmwater sampling periods. We also compared fish community composition and the probability an un-notched and notched dike structure and channel sand bar (referred to as channel structures) was occupied by various fish species. Few differences in species richness and diversity were evident among channel structures. Notching a dike structure had no effect on proportional abundance for any habitat guild. Catch per unit effort (CPUE) was greater at notched dikes for only three (lake sturgeon Acipenser fulvescens, paddlefish Polyodon spathula, and shovelnose sturgeon Scaphirhynchus platorynchus) of 12 great river species. Occupancy at notched dikes increased for blue catfish Ictalurus furcatus and decreased for blue sucker Cycleptus elongatus, but did not differ for 17 (81%) other species. No distinct increase in occupancy at natural channel sand bars compared to engineered dike structures was evident. Mean CPUE was higher in dike structures than channel sand bars for four great river species (goldeye Hiodon alosoides, lake sturgeon, paddlefish, and shortnose gar Lepisosteus platostomus), but did not differ for ten. Our results suggest dike structures may provide necessary habitats for many fluvial species when compared to channel sand bars, but notching did not increase abundance or occupancy of most native Missouri River fishes.

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