Is Lak Lake overfished?

摘要

Fish yields from Lak Lake increased by 2.3 percent between August 1997 and July 1999, and landed value by 14.1 percent. However, the status of the Lak fishery is highly species-specific, amounting to an estimated annual yield of 126-130 kg/ha. Over two years of surveys, the study has identified 40 fish species from catches in the lake. Fourteen major species accounted for an estimated 89.2 percent of the total yield over the two years. Six major gears account for most of the catch from Lak: fence-nets, gill-nets, long-lines, lift-nets, shrimp traps, and electrofishing gear. Data on the effects of electrofishing have not been possible to collect, as electrofishing is now banned. Gill-nets and fence-nets accounted for a total of 84 percent of the entire recorded yield, and probably put excessive pressure on some species. While overall yield and landed value from the lake have not declined, species diversity and the abundance of native fish species appear to be reduced. Restrictions on increases in fenceand gill-netting, especially the use of small mesh sizes, appear advisable. Electrofishing, which is highly non-selective, should be discouraged, and efforts made to encourage the cooperation of the fishing community in adopting measures to assure yield sustainability.