Conservation and management of Lake Manapao (Philippines), a ‘Sinarapan’ (Mistichthys luzonensis) sanctuary: Status, problems and solutions

Abstract

Lake Manapao — a mountain lake in San Ramon, Buhi, Camarines Sur Province, Philippines — is the only natural habitat which supports a viable population of ‘Sinarapan’, Mistichthys luzonensis Smith (Gobiidae). This species is only 1.2 cm when adult and is considered the world's smallest commercial fish. The Lake Manapao population is especially important because of the near-total collapse of stocks of Sinarapan in Lakes Buhi and Bato, both in Camarines Sur, where the goby once formed the basis of commercial fishing. The reason for this decline is not known, but a brief history of Sinarapan fishery in Camarines Sur is presented and present concerns relating to the Lake Manapao sanctuary are highlighted.

In view of the urgent need to manage Lake Manapao and conserve this endangered goby, the paper focuses on three aspects of its biology: population dynamics (growth, mortality, exploitation rate, yield-per-recruit and virtual population analyses); the continuing threat posed by degradation of the lake's drainage basin due to logging, increasing human settlements near the lake, and illegal fishing; and the need to foster international linkages leading to collaborative researches on strategies for rational management of the sanctuary.

Aside from a fishing ban on Sinarapan in Lake Manapao, this paper advocates the immediate implementation of specific activities such as reduction through fishing of Sinarapan predators (Oreochromis, Ophicephalus and Clarias), prohibition of further fish introductions, and assignment of personnel to conduct studies and manage the sanctuary.