Species composition of anguillid glass eels recruited at southern Mindanao Island, the Philippines

Abstract

Commercial exploitation of tropical Anguilla species has been expanding rapidly in Southeast Asia, even though their ecological status is unknown. In the present study, we investigated the species composition of anguillid glass eels recruited in southern Mindanao, the Philippines. The glass eel specimens were collected monthly between April 2014 and March 2015 in General Santos and identified by morphological and genetic analyses (n = 4745). Among the seven species/subspecies identified, A. marmorata was the dominant species (76.1 %), A. bicolor pacifica was the second most abundant (19.5 %), and A. celebesensis, A. interioris, A. luzonensis, A. borneensis, and A. japonica rarely occurred (0.02–3.0 %). In addition, caudal fin pigmentation, which is an important diagnostic trait at the glass eel stage, was found to be similar in the short-finned A. bicolor pacifica and the long-finned A. interioris and A. borneensis. The recruitment of Anguilla in the Philippine archipelago comprises seven anguillid species, including endangered, vulnerable, and data deficient species, according to the latest IUCN Red List assessment. The results of the present study provide essential information for future studies of tropical anguillid species, and might contribute to the development of strategies for the management of their stocks.