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Non-lethal human disturbances are often drivers of change in animal population and community structure. To gauge their severity, short-term behaviour (e.g. avoidance and habituation) has been argued to be a sensitive measure. However, many of these behavioural changes may occur only if disturbance-free habitat is readily accessible. In coral-reef fish, we tested whether human disturbances from intensive (i.e. loud music, swimming, snorkelling, splashing and fish feeding by numerous visitors) tourist visitations resulted in assemblage structure shifts led by shortterm behaviour. We monitored fish assemblage before, during and after tourist visitations to monitor changes associated with behaviour. Additionally, we monitored two adjacent reefs not visited by tourists because of difficult approach by boat. We posited that if short-term benefits of relocating to disturbance-free habitat outweigh the costs of tolerating disturbances, fish assemblage structure should shift along with tourist visitation levels. By contrast, if sensitive species are unable or unwilling to relocate, we predicted greater levels of assemblage heterogeneity between the visited and control reefs. Our results showed that in situ human visitations led to significant shifts in assemblage structure, resulting from short-term behavioural changes. Additionally, we showed significant between-reefs differences, whereby control reefs were characterised by higher species richness, larger fish sizes and variations in relative trophic guild prevalence. Our results suggest that short-term relocations to adjacent disturbance-free reefs may not mitigate the effects of human disturbances.

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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).

Intertidal reef environments are facing a global crisis as climate changes are causing sea-level rise. Synergistically, other human-induced impacts (e.g., sewage, habitat loss) caused by concentration of human populations near the coast increase the natural vulnerability of intertidal ecosystems. However, the effect of these threats have long been neglected due, in part, to a limited knowledge of some aspects of intertidal fish ecology. We tested what are the main differences and drivers in fish assemblages structure between tidepools in three oceanic and three continental shelf (coastal) sites of the tropical southwestern Atlantic (Brazilian Province) using standardized sampling methods. Oceanic and coastal fish assemblages were distinctly structured at the trophic and composition levels. The noteworthy endemism species rate (38–44%) and high densities in oceanic sites are supported by resident species restricted to mid and high-shore tidepools where herbivores were the major trophic group. The coastal sites, on the other hand, were dominated by widely distributed and carnivore species. Physical (substrate type, pool height, subtidal distance and rock coverage), biological (sessile animal coverage) and chemical (salinity) parameters act as the driving forces influencing fish spatial occupancy. Here, clear evidences of high fish endemism and importance of endemics structuring oceanic communities may act as the last straw in favor of the conservation of oceanic intertidal reefs.

While there is already a comprehensive understanding of the effects of environmental variables, such as dissolved oxygen, temperature and salinity, on the structure, biomass and metabolism of aquatic biota in estuarine habitats, the effect of sedimentation, a harmful underlying factor, remains unclear. The aim of this study was to assess the differences in fish assemblages along the freshwater to salt water gradient of a large tropical estuary, and to evaluate the effects on them of habitat disturbance associated with shallow water sedimentation in the intertidal areas. Fish and environmental variables were recorded in the upper, middle and lower salinity zones of the estuary at ebb tide in both the dry and wet seasons. Sediment samples associated with different levels of habitat disturbance were analysed using granulometry, and their organic content and dissolved oxygen levels were quantified. Water temperature, salinity, pH and dissolved oxygen levels were also measured. Habitat disturbance was found to be correlated with the density, biomass and richness of fish assemblages. A total of 77 species were recorded, forming two distinct fish assemblages, with the Eleotridae family dominating in the upper zone, and Gerreidae, Gobiidae and Tetraodontidae the most common in the middle and lower estuary. Changes in the structure of fish assemblages, including reductions in density, biomass and richness, were associated with disturbance to natural features, where muddy sediment was replaced by sandy sediment and the quantity of organic matter fell. Atherinella brasiliensis was the species which showed a preference for the disturbed areas in the middle and lower zones, while Dormitator maculatus showed a preference for them in the upper estuary. They may be taken as indicators of habitat disturbance due to shallow sedimentation.