Relative Abundance and Diversity of Fishes Caught by Beach Seine and Drift Longline in the Coastal Waters of Brgy. Sta. Monica, Infanta, Quezon (2003)

Abstract

The relative abundance and diversity of a multispecies fishery in Brgy. Sta. Monica, Infanta, Quezon, were studied using catches from beach seines and drift longlines from January 2003 to February 2003. Approximately 9,794 individuals (TW=96,688.5 g) of at least 58 species belonging to 37 genera and 26 families were caught by these gears during the study. Encrasicholina punctifer (RA=46.21% and RD=76.67%) and Nemipterus bathybius (RA=14.82% and RD=22.28%) were the most abundant and dominant in the beach seine (CPUE=10,468.83 g/hr) and drift longline (CPUE=955.84 g/hr) catch, respectively. Majority of species with n>10 that were tallied for their size distribution had mean lengths significantly less (P<0.05) than the reported mean lengths of the Food and Agriculture Organization (FAO) in 1999 and Fish Base in 2000. Family Leiognathidae and Trichiuridae had the shortest and longest sizes with mean lengths of 6 cm and 49 cm, respectively. Isometric and negative allometric growth was exhibited by the beach seine and drift longline catch, respectively. Isometric growth was exhibited by the fish assemblage of Brgy. Sta. Monica whose length-weight relationship (LWR) had a mean exponent (b=2.77), which was not significantly less than 3 (t=1.105, df=15, P>0.05). Diversity indices for the drift longline (H’=4.06; D=6.08; and J=1.16) were higher than those computed for the beach seine (H’=1.08; D=2.84; and J= 0.33). Mean diversity index for Brgy. Sta. Monica is as follows: H’=1.28; D=6.20; and J=0.32.