A multimetric index based on fish fauna for the evaluation of the biotic integrity of streams at a mesohabitat scale

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influência da estrutura do hábitat sobre a ictiofauna de um riacho em uma micro-bacia de pastagem, São Paulo, Brasil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Temporal distribution and composition of the ichthyoplankton from Leopoldo's Inlet on the Upper Parana River floodplain (Brazil)

Temporal distribution and composition of ichthyoplankton and their relationships with some environmental variables of Leopoldo's Inlet (Ressaco do Leopoldo) on the upper Parana River floodplain, southern Brazil, were analysed. Samples were taken from February 1991 to February 1992, and 3480 larvae were collected. The highest density of larvae was observed in November 1991 (36.79 larvae/ 10 m(3)) at night (night/day ratio 7: 1). Species composition showed a predominance of Characiformes (80%). There was a high density (4.28 larvae/10 m(3)) of Bryconamericus stramineus throughout almost the whole study period, the majority of the species were more frequently collected at night. Pearson's correlation indicated a relationship between larval density, temperature, and pluviometric index. Leopoldo's Inlet, whose ichthyofauna is mainly composed of grazing and resident species. shows favourable conditions for fish reproduction and development.

Food resources partitioning among sciaenid fishes (Perciformes, Sciaenidae) of the Flamengo bay, Ubatuba, southeastern Brazil

The determination of the diet and feeding habits is one of the principal aspects of the study on fish biology, as feeding is a basic process and its study is necessary for the understanding of the populations' dynamic and ecology. The Sciaenidae family has a significant occurrence in the bay's demersal ichthyofauna, constituting an important fishing resource. The goal of this work was to analyze how the partitioning of available food resources takes place among the ten sciaenid species which live in the Flamengo Bay. One single survey, consisting of three trawls, was carried out with a fishing boat equipped with two otter-trawl. Diet analysis showed that all species are exclusively carnivore, using several items as food, but crustaceans are the main food ingested. The use of the ''Proportional Overlap Index'' showed possible overlapping between six couples of species but in the majority of cases, morphologic differences between these species, such as the mouth position, probably determine different foraging strategies.

Artificial reefs and their effects on fish assemblages in a Brazilian reservoir and Tailrace

In this paper, we evaluate the effects of artificial reefs on fish assemblages in a hypereutrophic reservoir and in the lotic zone immediately below dam. Fish diversity was highest in the lotic zone relative to the reservoir. We also found an inverse relationship between diversity and distance from the river margin. Catches near the artificial reefs were more diverse than in control areas. A seasonal effect, possibly caused by variation in temperature, was significant in all comparisons. We argue that, in a scale of local effects, the ecological function of these structures would be similar to refuges.

Composição e abundância da ictiofauna na zona litorânea de um tributário, na zona de sua desembocadura no reservatório de Jurumirim, Estado de São Paulo, Brasil

Monthly collections of fishes using a trawl net were carried out from August 1996 to December 1997 with the objective of evaluating the composition and diversity of fish species in the littoral area of the transition zone between Veados Stream and Jurumirim Dam (Upper Paranapanema River, São Paulo State). Diversity and similarity indices of ichthyofauna at the sites were determined and correlated with abiotic factors such as dissolved oxygen, temperature, pluviometric precipitation and hydrological level. Twenty-six (26) fish species (the majority small-sized) of the family Characidae (Tetragonopterinae and Cheirodontinae) were registered. Representatives of the orders Siluformes, Gymnotiformes, Perciformes and Synbranchiformes occurred in lower abundance. Significant differences were found in the site diversity indices, but not in the abiotic factors. Significant correlations between the abundance of the ichthyofauna and the variations in the abiotic factors were not detected. The presence of fish larvae in the samples indicates the importance of the transition zone as a reproduction area of the fish species registered in this study.

Factors affecting fish diversity and abundance in drying ponds and lagoons in the upper Paraná River basin, Brazil

Monthly samples were taken from April 1992 to March 1993 of fish assemblages present in six permanent lagoons and four ponds, fragmented from them during the drought period and during the terminal phases of desiccation, to evaluate changes in their diversity, abundance and dominance. Their relationships with hydrological and environment conditions were examined. A total of 63 fish species were identified. Species composition and abiotic factors were heterogeneous among the different water bodies. The proportion of piscivores and oxygen concentration were the determining factors for structuring the assemblages. The impact of piscivory upon fish diversity was neutral at the beginning and negative at the end of the dry season. In the terminal phase of desiccation, diversity was higher in ponds that contained a moderate proportion of piscivores than in these containing a higher proportion.

Habitat, distribuição e aspectos adaptativos de peixes da microbacia do ribeirão Grande, Estado de São Paulo, Brasil

The ichthyofauna of ribeirão Grande microbasin that runs through one of the few remaining fragments of Atlantic Forest (in Mantiqueira mountain range, Valley of Paraíba) was studied. Fish samples were obtained with an electric fishing powered by a maximum capacity generator of 155 V and 60-Hz alterning current, gill-nets and traps. In three collecting days, during July/2001, October/2001, January/2002 and April/2002, 2865 fishes were sampled. These fishes belonged to 12 families, 23 genera and 37 species. The species were more abundant between the piedmont and the plain of the Valley of Paraíba. The Characidium, Trichomycterus genera and the Imparfinis minutus species presented only one ovary or testis and no swim bladder. The ecological significance of morphological features in stream mountain fishes was used to predict the niche adaptation for those conditions, towards K-strategy.

Alien fishes in lakes of the Doce river basin (Brazil): Range, new occurrences and conservation of native communities

The present study shows the distribution of alien fish species in tropical lakes in the middle Doce river basin, southeastern Brazil, obtained from a rapid assessment program. The causes for their introductions were sport-fishing improvement in some specific lakes and aquaculture in the studied basin. Presently, these species have a wide distribution occurring in 41 of the 54 lakes studied, representing an actual threat to regional native fish community. The natural connection among lakes and streams during the rainy season and the dispersal mediated by local people are the main invasion agents for alien fishes. The success of these invaders is probably due to absence of pre-existing effective competitors or top-predators in the invaded communities. We consider that the eradication of alien fishes by means of the available management tools may be very difficult due to the large number of lakes invaded and to the wide spectrum of lake conditions and resources exploited by these alien species. We recommend the use of environmental education as a tool to stop the human-mediated dispersion of aliens and to improve conservation of native fish community in lakes where these alien species are not present yet. © 2004 Instituto de Ciências Biológicas - UFMG.

Ocorrência do peixe-pescador-branco, Lophiodes beroe Caruso, 1981 (Lophiiformes: Lophiidae), em águas brasileiras

One specimen of the lophiid white anglerfish, Lophiodes beroe was collected for the second time in Brazilian waters, which far extends the limit distribution of the species to southeastern region (25°00'08).

Fish fauna of headwater streams that cross the Atlantic forest of South São Paulo state

The fishes of the present study were collected in the headwater streams of the Sorocaba, Paranapanema and Ribeira de Iguape river basins during the dry period in 2010. A total of 2892 fishes, grouped in 53 species, were captured. The composition of the ichthyofauna captured in the streams of Sorocaba and Paranapanema river basin was greatly similar. On the other hand, the fish fauna of the streams of Ribeira de Iguape river basin were quite different from the ones captured in the others basins, with the occurrence of endangered species (Isbrueckerichthys epakmos and I. duseni) and exotic species (Misgurnus anguillicaudatus). The previous list of fish for the Sorocaba river basin increased with the addition of seven species of Characiformes, one Gymnotiformes and four Siluriformes. © 2012 Check List and Authors.

Can DNA barcoding accurately discriminate megadiverse Neotropical freshwater fish fauna?

Background: The megadiverse Neotropical freshwater ichthyofauna is the richest in the world with approximately 6,000 recognized species. Interestingly, they are distributed among only 17 orders, and almost 80% of them belong to only three orders: Characiformes, Siluriformes and Perciformes. Moreover, evidence based on molecular data has shown that most of the diversification of the Neotropical ichthyofauna occurred recently. These characteristics make the taxonomy and identification of this fauna a great challenge, even when using molecular approaches. In this context, the present study aimed to test the effectiveness of the barcoding methodology (COI gene) to identify the mega diverse freshwater fish fauna from the Neotropical region. For this purpose, 254 species of fishes were analyzed from the Upper Parana River basin, an area representative of the larger Neotropical region.Results: Of the 254 species analyzed, 252 were correctly identified by their barcode sequences (99.2%). The main K2P intra- and inter-specific genetic divergence values (0.3% and 6.8%, respectively) were relatively low compared with similar values reported in the literature, reflecting the higher number of closely related species belonging to a few higher taxa and their recent radiation. Moreover, for 84 pairs of species that showed low levels of genetic divergence (<2%), application of a complementary character-based nucleotide diagnostic approach proved useful in discriminating them. Additionally, 14 species displayed high intra-specific genetic divergence (>2%), pointing to at least 23 strong candidates for new species.Conclusions: Our study is the first to examine a large number of freshwater fish species from the Neotropical area, including a large number of closely related species. The results confirmed the efficacy of the barcoding methodology to identify a recently radiated, megadiverse fauna, discriminating 99.2% of the analyzed species. The power of the barcode sequences to identify species, even with low interspecific divergence, gives us an idea of the distribution of inter-specific genetic divergence in these megadiverse fauna. The results also revealed hidden genetic divergences suggestive of reproductive isolation and putative cryptic speciation in some species (23 candidates for new species). Finally, our study constituted an important contribution to the international Barcoding of Life (iBOL.org) project, providing barcode sequences for use in identification of these species by experts and non-experts, and allowing them to be available for use in other applications. © 2013 Pereira et al.; licensee BioMed Central Ltd.

Interference of cage fish farm on diet, condition factor and numeric abundance on wild fish in a Neotropical reservoir

Historically, the ichthyofauna of large Brazilian rivers has been subject to anthropogenic interference, such as impoundments. Currently, cage fish farming systems are a new source of impact on aquatic ecosystems. The objective of this study was to characterise the impact of freshwater fish farms on the feeding of five species of Neotropical freshwater fish. Specimens of Astyanax altiparanae, Galeocharax knerii, Iheringicthys labrosus, Pimelodus maculatus and Plagioscion squamosissimus were sampled in areas around two systems of cage fish farming (CF), and two control areas (CT) that were not influenced by this activity. Results show that there were significant changes in the diet of trophic generalist species (A. altiparanae, P. maculatus and I. labrosus) accompanied by a related increase in the condition factor values of these species in cage areas. Trophic specialist species, such as the carnivorous fish species G. knerii and P. squamosissimus, presented small differences between the CF and CT areas with regard to diet and showed no differences in other analyses performed. In conclusion, cage fish farms can affect the natural diet of trophic generalist fish species, directly affecting the nutritional status (condition factor), where food wastes was found to be one of the principal items consumed by this trophic guild. Results indicate that these species are responsible for recycling a great quantity of organic matter transferred by this type of activity, which, along with local fishery activities, contribute to mitigation of associated processes of eutrophication. © 2013 Elsevier B.V.

Ictiofauna nos trechos médio e baixo rio Pardo, Alto Paraná: inventário

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

As assembléias de peixes da represa de Jurumirim (alto rio Paranapanema, SP): status atual e mudanças históricas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)