Status of Taal Lake Fishery Resources with Emphasis on the Endemic Freshwater Sardine, Sardinella tawilis (Herre, 1927)

Abstract

Assessment of fisheries in Taal Lake was conducted from 1996-2000 and 2008-2011 to know the status of the commercially important fishes with emphasis on the endemic freshwater sardine, Sardinella tawilis. Results of the fish landed catch survey in 11 coastal towns of the lake showed a decreasing fish harvest in the open fisheries from 1,420 MT to 460 MT in 1996 to 2011. Inventory of fisherfolk, boat, and gear also decreased to 16%, 7%, and 39%, respectively from 1998 to 2011. The most dominant gear is gill net which is about 53% of the total gear used in the lake with a declining catch per unit effort (CPUE) of 11kg/day to 4 kg/day from 1997 to 2011. Active gear such as motorized push net, ring net, and beach seine also operated in the lake with a CPUE ranging from 48 kg/day to 2,504 kg/day. There were 43 fish species identified in which S. tawilis dominated the catch for the last decade. However, its harvest also declined from 744 to 71 mt in 1996 to 2011. The presence of alien species such as jaguar fish, pangasius, and black-chinned tilapia amplified in 2009. Population parameters of S. tawilis from 2009 to 2011 were estimated using the FiSAT (FAO-ICLARM Stock Assessment Tool) software. The analysis of length frequency data showed an estimated L∞ of 15.40 to 16.36 cm and K value ranged from 0.53 to 0.73. The total mortality (Z) ranged from 3.01 to 5.03, natural mortality (M) from 1.44 to 1.75, fishing mortality (F) from 1.57 to 3.28 and exploitation rate (E) from 0.52 to 0.65. The high values of fishing mortality and exploitation rates indicate unsustainable fishing practices. Conservation and management measures of the fishery resources in the lake were recommended for appropriate action of the Protected Area Management Board (PAMB)