Distribuição, dominância e estrutura de tamanhos da assembleia de peixes da lagoa Mangueira, sul do Brasil

Abstract

ABSTRACT. Distribution, dominance and sizes structure of the fish assemblage in the Mangueira lake, southern Brazil. This study presents the composition of species, the distribution and dominance patterns, and the structure of sizes of the assemblage of fish in distinct habitats (littoral, deeper and near shore limnetic zone) of the Mangueira lake, in the southern Brazil. Samples were taken in the north, south and central regions of the lake from 2001 to 2007 using a multi-gear approach (gillnet, cast net, beach seine, dip net and bottom trawling). A total of 52 species were identified, 46 in the littoral zone, 33 in the near shore limnetic zone and 26 in the deep zone, distributed in 17 families, of the which, Characidae, Cichlidae, Loricariidae, and Atherinopsidae were the most diverse. The dominant species summed up 91.1 %, 92.9 % and 82.7 % of the all individuals caught in the littoral, deeper and limnetic zone, respectively. The littoral zone was comprised of small fishes, nearly 70 % between 25 and 50 TL mm. The dominance patterns showed that, in this zone, 19,5 % of the species were dominant, although four of those also prevailed in the other zones. In the deep zone, 7,6% of the captured species were dominant, with similar sizes to the littoral zone. For the other species, the sizes resemble to the near shore limnetic zone. The near shore limnetic zone was comprised of larger fishes, the major part between 150 and 200 TL mm, such as the great characins, the toothless characin and the silverside fishes. A larger difference was observed in the composition of species between the littoral and limnetic zones, with the species Jenynsia multidentata, Bryconamericus iheringii, Hyphessobrycon luetkenii and Gymnogeophagus gymnogenys dominating exclusively in the littoral, and the species Oligosarcus jenynsii, Cyphocharax voga, Odontesthes perugiae and Astyanax fasciatus dominating exclusively the near shore limnetic zone. The littoral zone presented differences in the composition and dominance of the species among the portions north and south of the lake. The 52 species registered in this study represent a high diversity of fishes in Mangueira lake, specially when compared to other coastal lakes of RS. Differentiated patterns of composition and abundance of species seem to reflect characteristics different from the coastal habitats sampled. KEYWORDS. Coastal lakes, biodiversity, ichthyofauna.RESUMO. Este estudo apresenta a composição de espécies, os padrões de distribuição e dominância, e a estrutura de tamanhos da assembleia de peixes em diferentes unidades de hábitat (zonas litoral, profunda e limnética costeira) da lagoa Mangueira, no extremo sul do Brasil. As amostras foram obtidas no norte, centro e sul da lagoa, entre os anos de 2001 e 2007 utilizando-se de diversos amostradores (rede de emalhe, tarrafa, rede de arrasto de praia, puçá e rede de arrasto de fundo). Um total de 52 espécies foi identificado, 46 na zona litoral, 33 na limnética costeira e 26 na profunda, distribuídas em 17 famílias, das quais, Cha...

Ichthyofauna of the hydrographic basin of the Chasqueiro Stream (Mirim Lagoon system, southern Brazil): generating subsidies for conservation and management

“…Teixeira et al (2005) emphasize that the differences in physiography over a longitudinal gradient corresponded to the changes in the diversity and abundance of the fish assemblage, where species of Characiformes and Siluriformes have wide spatial distribution. The rarest species in the system were Trachelyopterus lucenai and Gymnotus pantherinus (0.004%), which corroborate data reported by Artioli et al (2009) in Mangueira Lagoon, Rio Grande do Sul state. Trachelyopterus lucenai is not considered a native species of the region, and might have come to the hydrographic basin through irrigation channels (rice fields) (Bertoletti et al 1992, Becker et al 2013.…”

“…BHAC also showed high species diversity compared to similar studies in aquatic systems. For example, in the coastal streams of austral Brazil, Bastos et al (2013) recorded a total of 41 species, while Artioli et al (2009) documented the occurrence of 52 species in Mangueira Lagoon, located in the same coastal plain, with the largest values comparable to those found in other aquatic environments in southern Brazil (Lucena et al 1994, Tagliani 1994, Malabarba et al 2009, Carvalho et al 2012. Lower numbers of species in the studies described above can be associated with the type of sampler, as well as lower environmental heterogeneity; however, the outstanding abundance of Characiformes and Siluriformes are documented for every location (Artioli et The downstream biotope presented the greatest richness, which may be related to increased diversity of habitats and micro habitats observed in this biotope, which corroborates the river continuum theory (Vannote et al 1980), where changes along the longitudinal gradient (upstream to downstream) tend to increase the biological diversity.…”

Diet and reproductive dynamics of Trachelyopterus lucenai (Siluriformes: Auchenipteridae) in subtropical coastal lagoons in southern Brazil

“…Using a combination of FO and PA, the items were rated on the following scale of relative importance (RI): 4 -abundant and frequent, 3 -abundant, 2 -frequent, 1 -present. Items classified as abundant and frequent were found to be dominant (ARTIOLI et al 2009). Subsequently, they were analyzed for temporal variation and between the sexes.…”

Diet of Lontra longicaudis (Olfers, 1818) (Carnivora: Mustelidae) in three limnic systems in Southern Rio Grande do Sul State, Brazil

“…The relative importance (RI) of each prey category (i) (mollusks, crustaceans, insects, fishes, amphibians, reptiles, birds, mammals) was verified for each system by the rate of FO of such prey category over the sum of the frequency of occurrence of all prey categories: RI = (FO i /∑FO)x100. The RI values of each prey category were compared to the mean and the categories with values over the mean were considered frequent (Artioli et al 2009). The food niche breadth was calculated for each sampled system.…”