Molecular identity and demographic responses to salinity of a freshwater strain of Brachionus plicatilis from the shallow Lake Patzcuaro, Mexico

Brachionus plicatilis is one of the most important rotifers used in aquaculture worldwide. We found a strain of B. plicatilis in Lake Patzcuaro, a shallow water body in Central Mexico, which also supports several species of endemic fish. Here we present an investigation of the life-table demography and population growth of B. plicatilis at salinities of 5, 10, 15, 20, and 25 g L-1, and the molecular identity of this rotifer, comparing its genetic relation with other related taxa. The experiments were conducted using standard cohorts in five replicates. We found that this strain of B. plicatilis was better adapted to low (5 and 10 g L-1) rather than high salinities, with the survivorship ranging from 15 to 18 days, but 50 % mortality of the population occurred by day 6. The population-growth rate varied from 0.2 to 0.35 d(-1). We discuss the results with reference to similar studies conducted on several strains and species of the Brachionus plicatilis complex and the importance of our findings for aquaculture of endemic fish from this ancient shallow lake.