The role of Poso estuary ecosystem in elver eels (Anguilla spp.) anadromous migration

Estuaries are one of the most productive ecosystems of theworld, man fish species have evolved their life histories that take ad­ vantage of the high primary and secondary productivity. Most fishes in estuarine communities are juveniles, estuaries are often the nurser ground for fishes.The Poso estuary is invaded ever season b hundred of thou­sands of elvers Anguilla spp. (eel larvae). This invasion begin in April and reach its maximum in June to July. The elvers arrived from sea, from the Bay of Tomini. Migration into the estuarine occurs during a dark moon night. The advantages of the Paso estuary to the migratory elver are its high productivity, favorable water quality, abundant phsi­ cal shelter, low incidence of piscivous predator, and abundant food suppl that facilitate the rapid elver grouth. The upriver migration of glass eels from the sea to freshwater in European and North African countries has given rise to commercial fisheries. In Indonesia, elver exploitation has developed in several es­ tuaries. Glasseels fishing in the estuaries is a shore-based artisanal fishing dip-net. Fishing take place mainly at night and some did it during daytime. Poso estuary is the single estuary that supports eels to LakePoso, the eels in the lake originate from elvers ascending from the es­ tuar to the lake elevation of 500 m above sea level. Eel catch in Lake Poso was reported 30 ton in 1998. This high figure shous the impor­ tance of Poso estuary for the continuation of eel life cycle. In future planning and utilization of the Poso estuary the Provincial government must consider this elver potential seriously.