SIZE STRUCTURE AND REPRODUCTIVE PHENOLOGY OF THE SUCKERMOUTH SAILFIN CATFISH Pterygoplichthys disjunctivus WEBER 1991 FROM MARIKINA RIVER PHILIPPINES
The length weight relationships (LWR) sex ratio and gonado somatic index (GSI) of the suckermouth sailfin catfish Pterygoplichthys disjunctivus caught in 2010 2011 from Marikina River, Philippines was reported to provide information essential for management of this invasive species in non native ranges. Pooled LWRs for males and females was expressed by Log W= 0.1396 (LS) 2.74 (r 2 =0.975) suggesting negative allometric growth. Gonadosomatic index show a peak in reproduction during the rainy months (June August) Sex ratio did not deviate from the 1:1 ratio, although females were more numerous during the spawning season. Males dominated the larger size classes (41 45 cm SL) Females are highly fecund and are spawning capable even at smaller sizes compared to its congeners.