RESUMO
Temporal changes in larval fish species composition and abundance compared with other components of the seston are described in four estuarine habitats in the Atrato Delta, Colombia. In comparison with zooplankton, fish larvae and egg density and anthropogenic debris abundance were low in the South Atrato Delta. Transparency, water temperature and chlorophyll a were the major factors influencing the spatiotemporal distribution of ichthyoplankton in the delta. The most abundant fish larvae were Astyanax sp. 1, Anchovia clupeoides, Cetengraulis edentulus, Anchoa sp., Bathygbius curacao, Dormitator maculatus, Hyporhamphus sp., Atherinella blackburni, Gobiosoma sp. 1 and Menticirrhus americanus (92·8% of total abundance). Spatial temporal analysis shows that in this delta, shrub (arracachal) and grass (eneal) habitats are important for freshwater and estuarine species, whilst mudflat and mangrove are important for estuarine species and estuarine-marine species, since most flexion and post-flexion stages of these species were found there. Anthropogenic debris density never surpassed the total ichthyoplankton density, but was ubiquitous. Shrub and mangrove habitats had higher densities of anthropogenic debris, since these are flood-stem habitats that trap solids.
Assuntos
Ecossistema , Peixes/fisiologia , Rios/química , Estações do Ano , Poluentes da Água , Zooplâncton/classificação , Animais , Região do Caribe , Peixes/classificação , Larva/classificação , Larva/fisiologia , Especificidade da EspécieRESUMO
A total of 66 fish species belonging to 32 families were recorded between November 2012 and April 2014 in the southern arm of the delta to the Atrato River. Total length (LT ; range: 1·7-48 cm), total mass (MT ), LT and MT relationships (b values ranged from 1·8 to 3·7, mostly with negative allometric growth), and LT frequency (for 25 species) were estimated for freshwater, estuarine and marine species. LT and MT of Porichthys pauciradiatus and Membras argentea are given for the first time and maximum LT records for 14 species exceed those in the literature.