Insights on Evaluating Commercially Important Macroinvertebrate Species in Danjugan Island Marine Reserve, Philippines.

The commercial importance of benthic macroinvertebrates like echinoderms and molluscs has led to the overexploitation of wild stocks in many areas around the Philippines. Despite their ecological and economic importance, studies on the status of wild populations of commercial macroinvertebrates in unexploited habitats such as marine protected areas (MPAs) are very scarce. The diversity and abundance of commercially valuable echinoderms and molluscs in the seagrass and reefs of Danjugan Island Marine Reserve were assessed. Shallow areas (1-3 m depth) around the island were surveyed both during the day and after dusk using belt transects. A total of 226 individuals belonging to 21 different taxa were recorded during the surveys, of which 71% were molluscs and 29% were echinoderms. In the seagrass habitat, Cypraeidae, Toxopneustidae, and Conidae were the dominant families, while molluscs from the Cardiidae family comprised more than half of the total assemblage in the reef flat. The most diverse commercial macroinvertebrate group was Holothuriidae with five different species. The densities of the families were higher during dusk than during the day in both habitats, except for Cardiidae in the seagrass. The highest values of species richness and H' index were observed during dusk surveys in the reef habitat (H'= 1.57), while the lowest was observed in seagrass areas during morning surveys (H'= 1.37). This is the first study that assessed commercially valuable macroinvertebrates during day and night in two connected habitats within a protected area. The differences in diversity and abundance in each habitat depending on the time of day highlight the importance of considering these factors when evaluating macroinvertebrate populations in unexploited areas. [ABSTRACT FROM AUTHOR]