Anchialine crustaceans (Crustacea: Decapoda) from Siquijor Island, Philippines

Crustaceans occurring in the anchialine ponds of Siquijor Island are reported for the first time. The crustacean fauna in anchialine habitats consist of two species of shrimps and four species of crabs. Physico-chemical parameters measured in situ during the survey show typical characteristics of tropical anchialine habitats, i.e., subsurface temperatures ranged from 25°C to 29.6°C (mean ± standard deviation, throughout = 28.26 ± 1.87°C); pH of about 7.0; low dissolved oxygen (DO) level from 4.5 mg/L to 6.63 mg/L (5.93 ± 0.87 mg/L); and higher salinity in an open anchialine pool (21.7‰, Cambakjaw) than in anchialine caves, from 5.5‰ to 13.3‰ (12.18 ± 6.21‰). Degradation of anchialine habitats were observed as a result of agriculture run-off, human utilization (e.g., bathing and laundry) and, in one case, introduction of Tilapia Oreochromis niloticus.