〈原著〉フィリピン・ビサヤ諸島において漁獲される干潟棲貝類の販売量および種構成の変化とその要因の検討〈原著〉フィリピン・ビサヤ諸島において漁獲される干潟棲貝類の販売量および種構成の変化とその要因の検討 〈Original〉Changes in quantity and species composition of tidal flat inhabiting mollusks sold at the local markets of Visayas Islands, Philippines
[Synopsis]Degradation of the Philippines’ coastal environment with economic growth is expected to negatively impact tidal flat inhabiting mollusks. But there are few studies investigating local changes in quantity and species composition of Philippine tidal flat mollusks. This study surveyed the quantity and species composition of tidal flat mollusks at several coastal sites and those being sold at the local markets of the Visayas, Philippines, compared the results between sites and against previous studies, and estimated current resource quantity and ecological status of the tidal flat habitat. The total volume of mollusks sold in Cebu –significantly, mollusks from mangrove and freshwater habitats have decreased as compared to 30 years past. No change in volume was found in Dumaguete, Negros Island. The results indicate decreasing population and species number of mollusks in the tidal flats of Cebu possibly caused by worsening coastal degradation due to widespread urbanization of the island. This study suggests implementation of mollusk resource management and prevention of further coastal environment disturbance and over-exploitation of coastal resources in the Visayas, Philippines.