Submitted by Ricardo Cedraz Duque Moliterno (ricardo.moliterno@uefs.br) on 2016-03-01T00:26:45Z No. of bitstreams: 1 Disserta??o Luiz Alberto.pdf: 2080024 bytes, checksum: e6fbb727385961e9b7622db8acdbd075 (MD5) / Made available in DSpace on 2016-03-01T00:26:45Z (GMT). No. of bitstreams: 1 Disserta??o Luiz Alberto.pdf: 2080024 bytes, checksum: e6fbb727385961e9b7622db8acdbd075 (MD5) Previous issue date: 2013-02-04 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / A year-long otter trawl survey in the Todos os Santos bay (TSB) was conducted between November 2011 and September 2012 with the aim of describing the composition and structure of fish communities of the bay and check community fluctuations in both periods of the hydrological cycle (dry and wet). Fifty-three morphospecies were catch, comprising 10 orders and 29 families. The most representative families in terms of species richness were, respectively, Carangidae, Gerreidae, Syngnathidae, Engraulidae, Gobiidae and Paralichthyidae. Despite the significant number of species caught, the fish community of the Todos os Santos bay, on the beaches sampled with trawl, is dominated by five species: Atherinella brasiliensis, Sphoeroides greeleyi, Eucinostomus argenteus, Sphoeroides testudineus and Lile piquitinga, which represent 99.5% of the relative importance of the catch. Influences of environmental parameters of rainfall, temperature and salinity on the composition and structure of fish fauna of TSB were absent or very subtle. The use of different fishing gear (simple net and with bag) did not influence the values of CPUE for different beaches sampled. We can conclude that the shallow areas of the Todos os Santos bay have quite important for maintaining their fish stocks, since species (including commercial interest) to use, partially or completely, the TSB as nursery or creation area. / Um programa de amostragens bimstrais de arrasto de praia em seis esta??es de coleta na Ba?a de Todos os Santos (BTS) foi realizado entre novembro de 2011 e setembro de 2012 com o objetivo de descrever a composi??o e estrutura da comunidade de peixes da ba?a e verificar flutua??es da comunidade nos dois per?odos do ciclo hidrol?gico (seco e chuvoso). Cinquenta e tr?s morfoesp?cies de peixes foram levantadas, compreendendo 10 ordens e 29 fam?lias. As fam?lias mais representativas em termos de riqueza de esp?cie foram, respectivamente, Carangidae, Gerreidae, Syngnathidae, Engraulidae, Gobiidae e Paralichthyidae. Apesar do n?mero relevante de esp?cies capturadas, a comunidade ?ctica da Ba?a de Todos os Santos, nas praias amostradas com arrasto manual, ? dominada, basicamente por cinco esp?cies: Atherinella brasiliensis, Sphoeroides greeleyi, Eucinostomus argenteus, Sphoeroides testudineus e Lile piquitinga, as quais correspondem a 99.5% da import?ncia relativa das capturas. Influ?ncias dos par?metros ambientais de pluviosidade, temperatura e salinidade sobre a composi??o e estrutura da ictiofauna da BTS foram ausentes ou muito sutis. A utiliza??o de diferentes petrechos de pesca (rede simples e com saco) n?o influenciou nos valores de CPUE para as diferentes praias amostradas. O elevado n?mero de esp?cie tamb?m sugere que muitos peixes utilizam as zonas rasas da BTS como ?reas de cria??o, usufruindo da prote??o e alimento, portanto, pode-se concluir que as ?reas rasas da Ba?a de Todos os Santos possuem assaz import?ncia para manuten??o dos seus estoques pesqueiros, j? que esp?cies (inclusive de interesse comercial) a utilizam, parcial ou totalmente, como ?reas de ber??rio e/ou cria??o.

Fischgemeinschaften in Seen sind zunehmenden Umweltveränderungen unterworfen. Die Analyse des Einflusses abiotischer und biotischer Faktoren auf die Größenstruktur von Fischgemeinschaften ist entscheidend, um die Entwicklung von Seeökosystemen im Zuge von Umweltveränderungen vorhersagen zu können. Es ist jedoch schwierig Fische in Seen zu beproben, da Fanggeräte selektiv sind. Die Qualität und Vergleichbarkeit von Fischfängen durch Angler, Kiemennetze, Schleppnetze und Hydroakustik wurden untersucht. Anglerfänge eignen sich begrenzt für vergleichende Fischbestandsuntersuchungen. Vertikale Hydroakustik eignet sich für die Fischbiomassequantifizierung in geschichteten Seen. Der Beprobungsaufwand von Kiemennetzen kann reduziert werden, wenn zeitnah hydroakustische Untersuchungen statt finden. Schleppnetze eignen sich für die Beprobung von pelagischen Fischen in tiefen Seen. Die Größenstruktur von Fischgemeinschaften unterschied sich auf regionaler und überregionaler Ebene entlang abiotischer und biotischer Gradienten. Die regionale Studie zeigte, dass tiefe nährstoffarme Seen mit hohen Raubfischabundanzen durch mehr große Fische gekennzeichnet waren. Nährstoffreiche Flachseen mit wenigen Raubfischen zeigten höhere Anteile von mittleren Fischgrößen. Im überregionalen Vergleich führten Temperaturpräferenzen der Fischarten zu zwei Fischgemeinschaften, die sich in ihrer Größenzusammensetzung unterschieden. Ein hoher Anteil großer Salmoniden war typisch für hochgelegene Kaltwasserseen im Norden und Süden Europas. Flachlandseen mit Kühl- und Warmwasserfischen zeichneten sich durch eine Dominanz von kleinen Fischen aus. Das lässt vermuten, dass Fischgemeinschaften in Flachlandseen relativ robust gegenüber Umweltveränderungen reagieren. Kaltwasserfischgemeinschaften könnten im Zuge der Klimaerwärmung starken Änderungen unterliegen, da eine Veränderung in der Artenzusammensetzung von einer Verschiebung in der Größenstruktur hin zu mehr kleinen Fischen begleitet sein wird. / Lake fish assemblages are increasingly exposed to environmental change in their habitats. The investigation of abiotic and biotic factors and their effects on the size structure of lake fish is essential for predicting the response of fish assemblages to environmental change. However, sampling of lake fish is challenging because sampling gears are selective. The quality and correspondence of fish catches from angling, gillnetting, trawling and hydroacoustics were analysed. Non-standardised catch data from recreational angling were of limited quality for a comparison of fish stocks. Vertical hydroacoustics is an efficient method to quantify fish biomass in stratified lakes. Sampling effort of multi-mesh gillnets can be reduced when fish abundance estimates are derived from contemporarily operating hydroacoustics. Trawling is useful to sample pelagic fish assemblages in deep lakes. The size structures of fish assemblages differed on a small and a large geographical scale along gradients of abiotic and biotic lake descriptors and differences in fish assemblage composition. At a small geographical scale assemblages in deep and less nutrient-rich lakes with high predator abundances were characterised by a higher proportion of large fish. Shallow nutrient-rich lakes with few predators were characterised by more medium-sized fish. At a large geographical scale thermal optima of fish generated two types of assemblages with different size structures. A high proportion of large salmonids was observed in coldwater lakes at high elevation sites in northern and southern Europe. Lowland lakes with cool- and warmwater fish were dominated by small-sized individuals. The results suggest that lowland lake fish assemblages are relatively robust against environmental change. Coldwater fish assemblages instead may suffer dramatic consequences from global warming as expected species shifts are likely to be accompanied by shifts in the size structure towards smaller individuals.