Larval feeding behaviour of the endangered fish golden bubblebee goodeid, Allotoca dugesi, implications for conservation of an endangered species

" To improve survival of cultured juvenile fishes, it is important to understand prey preferences and predation behaviour of fish larvae. In this study, the feeding behaviour and prey preference of Allotoca dugesi (Bean), a small fish species endemic to Mexico and currently threatened with extinction are presented. Three zooplanktonic prey, viz. Brachionus calyciflorus (Pallas), Moina macrocopa (Goulden) and Daphnia pulex (Leydig) were tested. The mean size (standard length ± SE, mm) of the larvae ranged from 9.0 ± 0.1 mm at week 1 to 18 ± 2 mm at the end of the experimental period (8 weeks). The gape size (mean ± SE) increased from 0.125 ± 0.002 mm at the first week to 2.300 ± 0.361 mm by the eighth week. Capture success (capture/attack) ranged from 0.80 to 0.98 with Brachionus, 0.72–0.94 with Moina and 0.17–0.46 with Daphnia. Prey preference experiments were conducted using B. calyciflorus, M. macrocopa and D. pulex at a fixed ratio of 5 : 2 : 2 ind. mL)1, respectively, and revealed a positive selection for rotifers and Moina, but avoidance of Daphnia. The results are discussed with reference to conservation efforts for Allotoca dugesi "