PADRÕES DE DISTRIBUIÇÃO E OCORRÊNCIA DO ICTIOPLÂNCTON NO MÉDIO RIO XINGU, BACIA AMAZÔNICA, BRASIL/DISTRIBUTION AND OCCURRENCE PATTERNS OF ICHTHYOPLANKTON IN THE MIDDLE RIVER XINGU, AMAZON BASIN, BRAZIL

Abundance and distribution of ichthyoplankton in the Volta Grande do Xingú, Pará, Brazil, are analyzed. Collections were undertaken during four campaigns in the local hydrological cycle phases, distributed into 16 sampling stations, featuring 95 eggs and 398 larvae of fish of 25 taxa belonging to 5 orders, 16 families, 19 genera and 18 species, of which 9 were the source of income, food and subsistence of the local population. Largest egg and larvae collection occurred during the night period, especially in places close to sand banks, lake entrances and along the tributaries. Data revealed a seasonal pattern where high ichthyoplankton abundance was related to the flood pulse and rainfall. The other variables (temperature, pH, OD and conductivity) also affected ichthyoplankton distribution differently. Results showed that the area studied is a spawning, breeding and egg and larvae dispersion of several fish species requiring preservation.