Ecology, distribution, and recruitment of conch (Gastropoda: Strombidae) in intertidal zones

Macroinvertebrates from Family Strombidae locally known as ‘’sikad-sikad’’ are some of the major gleaned species in the intertidal areas. This study investigated the ecology, abundance, distribution, and recruitment of conch species of Family Strombidae in the three coastal barangays (Pandaraonan, Dolores, and Tando) of Guimaras Island. The ecological aspects were assessed for three habitat types (seagrass beds, bare sand, and edges of mangrove areas) within each barangay. A total of 319 conch individuals were identified belonging to seven species (Canarium erythrinum, Canarium labiatum, Canarium mutabile, Canarium urceus, Conomurex luhuanus, Gibberelus gibbosus, and Laevistrombus canarium). The distribution of these species varied across habitats but were found most abundant in Enhalus acoroides and Thalassia hemprichii seagrass beds with patchy distribution exhibited by regular or clumping patterns. Shell lengths ranged from 15–50 mm with C. mutabile being the smallest and C. luhuanus and L. canarium as the largest species. Temporal assessment at one site (i.e., seagrass beds of Dolores) showed no significant variation in the abundance and size of adult conch species across monitoring months. However, conch juveniles assessed showed increasing trend in shell length (5, 8, and 12 mm) but with decreasing density (103, 104, and 90 individuals/m2) from February to April, and June 2023, respectively. This study provides relevant information in the development of policies to ensure sustainability of conch as a valuable fisheries commodity.