Chapter 21 - Sustainable management of tropical anguillid eels in Southeast Asia

Abstract

The anguillid eels of genus Anguilla are a catadromous fish species, recruiting from spawning ground in the ocean and staying their most lives in continental habitats and travelling again to the ocean for reproduction and end of life cycle. The eels are thought to be an important fishery and aquaculture resources from biological and ecological perspectives. The eel populations are highly fluctuating in terms of biotic and abiotic factors. Populations and abundance of temperate eels such as the European, American, Japanese and Australasian eels have declined severely over several decades. Glass eel recruitment in the European eel, the American eel, the Japanese eel and New Zealand longfin eel have declined by 90% to 99%, over 95%, 80% and 75%, respectively, since 1970s/1980s. The reasons of the decrease in stock and recruitment are not well understood, while some of the causes for the drastic decline are overfishing and overexploitation. Eel aquaculture still depends on wild juveniles and it is because commercial propagation has not yet been established, although it has succeeded under captive condition. Therefore, tropical eels from Southeast Asia are considered and targeted as important resources and productions for the eels to compensate the decline in temperate eel population from European and East Asian countries. However, there are few researches on fundamental biology and ecology and on conservation and management of tropical eels. Therefore, Southeast Asian countries must conduct biological study and stock assessment for the tropical eels immediately having responsibility for the sustainable management in the future.