Species composition of macroinvertebrates in Sto. Tomas Cove, La Union, Philippines

Abstract

Macroinvertebrates usually inhabit coastal areas. Being numerous in the shallow zones, they provide readily available food source. They are mostly exposed to high fishing pressure as most of them are immobile or slow moving andimals. Results of the three-year survey from 2013 August to June 2016 on the status of macroinvertebrates collected by a modified trawl net (locally known as Karkar) at four established stations in Sto. Tomas cove are presented in this study. This include species composition, abundance and distribution of invertebrates in the area. Four groups were identified: Mollusks, Arthropods, Echinoderms and Cnidarians. Of these, mollusks were the most diverse, widespread and common group throughout the sampling months. The mollusks consist of three groups in the collections: Bivalves, Gastropods and Cephalopods. Two species: T. terebra and A. pleuronectes represented the most abundant taxa. Arthropods were also abundant in the collected samples and consisted primarily important species such as shrimps (Metapenaeus spp.); crabs: Charybdis sp., Portunus sp., S. serrata and other species of Portunidae.  S. mantis is also common and abundant in the collected samples. Others were collected in small quantity. Echinoderms were less common and represented by two species of sea cucumbers (H. ocellata & H. scabra). Few samples of Cnidarians were collected and may come from other source or carried by water currents into the cove. They may also have entered the cove in search of food. Considering the catches of these resources, a need for an immediate action towards their sustainability seems necessary.