Reef fishes captured by recreational spearfishing on reefs of Bahia State, northeast Brazil. Biota Neotrop. 12(1): http:// www.biotaneotropica.org.br/v12n1/en/abstract?article+bn02012012012Abstract: Although recreational spearfishing is a growing activity, its impacts are poorly understood. This paper aims to present data on reef fishes captured by recreational spearfishing in the Bahia State, Northeastern Brazil. We analyzed 168 photos of spearfishing conducted in the reefs of this region between 2006 and 2008. A total of 1.121 fish belonging to 48 species were captured in three sub-regions of the Bahia coastline: Litoral Norte (LN), Salvador (SSA) and Baixo Sul (BS). The main species caught were: Scomberomorus brasiliensis (n = 191), Sphyraena barracuda (n = 153), Lutjanus jocu (n = 150) and Caranx bartholomaei (n = 141); these four species represented 56.5% of total captures. Over the sampling period, the highest values of catch rates per day were observed at BS, followed by SSA and LN. There were significant between-sites differences in the number of fish in the number of species caught. However, there were no significant between-years differences in the number of fish and numbers of species caught. The trophic classification of fish showed that carnivores (n = 623) were more frequently captured, followed by piscivores (n = 371), herbivores (n = 101) and invertivores (n = 26). The results showed that high sized, top predatory fishes, were the main targets, although other trophic levels were also captured. e Caranx bartholomaei (n = 141); estas quatro espécies representaram 56,5% do total de peixes capturados. Ao longo dos anos amostrados, foram registradas taxas mais elevadas de captura por dia em BS, seguido pelo SSA e LN. Foram encontradas diferenças significativas entre os locais estudados para a quantidade de peixes e o número de espécies capturadas. Entretanto, não foram encontradas diferenças significativas entre os anos para a quantidade de peixes e número de espécies capturadas. A classificação trófica de peixes mostrou que os carnívoros (n = 623) foram mais frequentemente capturados, seguidos de piscívoros (n = 371), herbívoros (n = 101) e invertívoros (n = 26). Os dados apresentados demonstram que grandes peixes predadores de topo são o alvo principal, no entanto outros níveis tróficos também são capturados. Palavras-chave: sobrepesca, recifes de coral, Salvador, Litoral Norte, Baixo Sul. Data AnalysisEach photograph corresponded to one fishery, and was considered as an independent sample. Spatial and temporal variations in total capture and richness (total number of species) were evaluated with nonparametric analysis of variance (Kruskall-Wallis test). Whenever differences were detected in the parameters, the Dunn's test was applied to the data in order to quantify and establish those differences.
Estuaries are areas of recognized importance in the development and sanctuaries of fishes and also a great source of fishing resources. This article presents an inventory of fishes from the Paraguaçu River estuary, Todos os Santos Bay, Bahia, Brazil. 28 points comprising the saline sections that may exist in a tropical estuary were sampled quarterly from March 2009 to February 2010 with the aid of bottom gill nets, surface gill nets, seine net and casting net. A total of 4.097 individuals were captured, belonging to 7 species of Chondrichthyes and 117 species of Actinopterygii (83 genera and 49 families). Most of the geographical extent of the estuary was sampled by assessing large spatial variability in fish assemblage structure. The curve of species accumulation (rarefaction) had stabilization with ½ of the samples. The general structure of the assemblage is described and commented trough evidences for a new spatial organization of the fish fauna due to dam effects upstream the estuary. Resumo: Estuários são áreas de reconhecida importância no desenvolvimento e refúgio dos peixes e também grande fonte de recursos pesqueiros. Este artigo apresenta um inventário dos peixes do estuário do Rio Paraguaçu, Baía de Todos os Santos, Bahia, Brasil. 28 pontos constituindo as três seções salinas que pode haver em um estuário tropical foram amostradas trimestralmente de março de 2009 a fevereiro de 2010 com auxílio de redes de espera de fundo, de superfície, redes de arrasto manual e tarrafas. Um total de 4.097 indivíduos foram capturados, pertencendo a 7 espécies de Chondrichthyes e 117 espécies de Actinopterygii (83 gêneros e 49 famílias). A maioria da extensão territorial do estuário foi amostrada para acessar maior variabilidade espacial na estrutura da assembléia de peixes. A curva de acumulação de espécies (rarefação) apresentou estabilização com ½ das amostras. A estrutura geral da assembléia é descrita e comentada através de evidências para uma nova organização espacial da fauna de peixes devido a efeitos de barragem a montante do estuário. Palavras-Chaves: inventário, peixes estuarinos, distribuição espacial, efeitos a montante, nordeste brasileiro. Biota Neotrop., vol. 10, no. 4 Keywords: inventory, estuarine fishes, spatial distribution, effects upstream, brazilian northeast. REIS-FILHO Material and MethodsFishes were collected at 28 points within the Paraguaçu River estuary with quarterly samples between March 2009 and February 2010 (Figure 1). Several types of collectors were used: for marginal environments and with depths up to 3 m, trawl manual (12 m × 2 m with 12 mm mesh), gillnets (100 m × 3 m with 15 mm mesh) and flue (casting net ) (10 mm mesh). For environments with depth between 4 and 20 m, bottom gill nets (300 m × 3 m with 20 mm, 30 mm, 40 mm, 50 mm and 60 mm mesh) and surface gill nets (200 m × 4 m with 15 mm mesh) were used. In order to evaluate the ichthyofauna distribution in the estuary, this one was segmented into three sections (lower, middle and upper).
The influence of the lunar phases and tidal range on the fish capture was analysed in a tidal flat in Barra do Paraguaçu (Baía de Todos os Santos). The sampling was realized in the flood tide and ebb tide of the spring (full moon) and neap (waning moon) tides, between June 2007 and May 2008. At all sampling occasions, two parallel drags were accomplished to the tidal flat, in the same direction of the current, in a 100 m long area marked on the beach beforehand, using a seine net of 15 m × 2.0 m with a mesh of 12 mm between adjacent knots. A total of 2312 fish specimens were captured (26.5 kg), belonging to 75 species from 45 families. The mean number of captured fish was significantly larger in full moon at ebb tides, while the mean weight in the captures was larger in ebb tides. There was significant difference in number of species, number of fish, richness and diversity between full and waning moons. The number of fish and biomass were significantly different between tides. Significant differences were found in community structure regarding trophic groups in relation to tide and moon, although the classic diversity indices did not capture this effect between tides. Furthermore, it was possible to identify preferences of occurrence related to the change of tide in dominant species.
A B S T R A C TThis study aims to describe for the first time the fish community structure of five shallow reefs located off the cities of Santa Cruz de Cabrália and Porto Seguro (Araripe-AR, Itacipanema-IT, Alagados-AL, Naufrágio-NA and Recife de Fora Marine Park-RF Reefs), South Bahia, Northeastern Brazil. Fish density and richness were assessed through stationary point counts of 2 m radius for small cryptic species and 3 m for more conspicuous species. A total of 1 802 fishes belonging to 23 families and 54 species were observed. The most abundant species were the pomacentrids Stegastes fuscus and Abudefduf saxatilis. No significant differences were found for species richness or density of conspicuous species, but density of small cryptic species was low on reefs with high bottom rugosity, where there were more holes and crevices available. Herbivores were dominant on AR, AL and RF, invertivores on AL and both groups were dominant on IT. Some habitat variables such as rugosity and benthic cover were strongly correlated to species and sites. High bottom heterogeneity was found among reefs but they still presented similar species composition, richness and density. Within small-scale studies, such similarities in composition and richness are to be expected for reef fish communities, as most of the species concerned have a wide distribution range. R E S U M OEste trabalho descreve pela primeira vez as comunidades de peixes em cinco recifes rasos de Santa Cruz de Cabrália e Porto Seguro (Araripe-AR, Itacipanema-IT, Alagados-AL, Naufrágio-NA e Recife de Fora Marine Park-RF), sul da Bahia, nordeste do Brasil. A densidade e riqueza foram obtidas utilizando censos estacionários de 2 m de raio para espécies pequenas e criptobênticas e 3 m de raio para espécies conspícuas. Um total de 1802 peixes pertencentes a 23 famílias e 54 espécies foram registrados, sendo as espécies mais abundantes dos pomacentrídeos Stegastes fuscus e Abudefduf saxatilis. Nenhuma diferença significativa foi encontrada para a riqueza entre os recifes e também para a densidade de espécies vágeis. Entretanto, a densidade de espécies criptobênticas foi mais alta em lugares com maior rugosidade. Herbívoros foram dominantes nos recifes AR, AL e RF, invertívoros em AL e a dominância dos dois grupos ocorreram em IT. Algumas variáveis ambientais como rugosidade e cobertura bentônica estão fortemente relacionadas às espécies e diferentes recifes. Estes são fisicamente heterogêneos, mas a composição e riqueza de espécies similares, o que seria esperado em comunidades recifais abrangendo estudos em pequena-escala, pois peixes recifais estão amplamente distribuídos.
The present study evaluated changes in an estuarine fish community caused by blooms of the dinoflagellate Akashiwo sanguinea. Samples were collected before, during and after the red tide using seine nets and surface and bottom nets in three areas near the affected area. The area was around the mouth of the Paraguaçu River. A total of 144 samples were collected, containing 1,989 individuals, with a total weight of 51.4 kg, belonging to 42 species in 29 families. During the red tide, fish density, richness and biomass decreased significantly. Atherinella brasiliensis and Sphoeroides greeleyi were the most abundant species during the red tide, indicating some possible resistance to the effects of the red tide. One month after the red tide, there was a rapid recovery of the density, biomass and richness of fish, and Cetengraulis edentulus was the most captured species. An important result of the present study is the finding that the dynamics of small populations of fish are often influenced by fortuitous events, and stochasticity may dominate. The establishment of a continuous and adequate monitoring program in the area may contribute to understanding the effects of red tides on fish population dynamics. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Southwestern Atlantic Ocean rocky shores sustain important reef fish communities. However, those communities in tropical regions are not well understood, especially in Brazil. In this present article we assess community parameters of reef fishes such as composition, trophic organization and their relationships with physical and biological factors on four tropical rocky shores in Todos os Santos Bay, southwestern Atlantic. During six months, a total of 80 visual censuses were performed, in which 3,582 fish belonging to 76 species were recorded. Territorial herbivorous fish and turf algae were dominant at all the sites. The spatial variability of fish community structure was related to the benthic cover composition and depth. The high abundance of territorial herbivores and mobile invertebrate feeders could be associated with high levels of turf cover, low wave exposure and shallow waters. Moreover, this fact could be a consequence of the low density of roving herbivores and large carnivores probably due to the pressure of intense fishing activity. Thus complementary studies are needed to evaluate the actual conservation status of these rocky shore reefs, singularly located habitats connecting inner and outer reefs in Todos os Santos Bay.
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