Growth, Survival, and Site Fidelity of Florida and Intergrade Largemouth Bass Stocked in a Tropical Reservoir

Abstract

Differential performance of genetic strains of largemouth bass Micropterus salmoides is an important management consideration. In Puerto Rico, largemouth bass are widely stocked without attention to which stock is the superior genetic stock for island reservoirs. We simultaneously stocked fingerling Florida largemouth bass M. s. floridanus and intergrade (hybrids of Florida and northern largemouth bass M. s. salmoides) largemouth bass at four sites within Lucchetti Reservoir, Puerto Rico. Recapture efforts 24–26 d following stocking revealed no differences in initial growth or survival. Dispersion from stocking sites varied among sites and between groups at two sites and for all sites pooled; Florida largemouth bass were significantly more mobile after stocking. Relative abundance of each group was similar at age 1, but Florida largemouth bass accounted for 76% of the catch at age 2 and 100% at ages 3 and 4. Initial growth rate was rapid for both groups (1.25 mm/d) until about 275 mm total length, but growth slowed to 0.25 mm/d by age 1 and was only 0.06 mm/d after age 2. Mean relative weight (W_r ) of intergrade largemouth bass was significantly higher than that of Florida largemouth bass at ages 1 and 2 during the spawning season (although the Florida groups' W_r remained at nearly 100). Because Florida largemouth bass displayed greater longevity, we recommend future stockings to use only this subspecies in Puerto Rico.