Alexis R. Alicea

The feeding dynamics of juvenile largemouth bass (Micropterus salmoides) were studied from March 1992 to December 1994 in Lucchetti Reservoir, Puerto Rico. Early piscivory by juvenile bass was aided by constant, but qualitatively variable, availability of fish prey items including threadfin shad (Dorosoma petenense), mozambique tilapia (Tilapia mossambica), redbreast tilapia (T. rendalli), and bluegills (Lepomis macrochirus). Threadfin shad was the primary food item for juvenile bass, supplemented by bluegills and tilapias when abundant. Insectivory was high in situations of low fish prey...

Although threadfin shad (Dorosoma petenense) have been widely introduced as forage fish, little is known about their natural history in tropical reservoirs. Gonadosomatic index (GSI) analysis of threadfin shad from Lucchetti Reservoir, Puerto Rico, indicated that most spawning occurred from January to June and again in October, but some spawning occurred year-round, except from mid-August to mid-September. Aging of sagittal otoliths indicated that total length (TL) increased with age (r2 = 0.36). Maximum length was 86 mm TL (N = 2,002) and maximum age was 141 days (N = 124). Hatch date...

The validity of otolith ageing in Puerto Rico was examined using known-age largemouth bass (Micropterus salmoides) in Lucchetti Reservoir. Age-0 largemouth bass were tagged with binary-coded wire microtags and stocked into the reservoir on 6 separate events between April 1992 and May 1996. Fish were collected throughout the study at ages 1-3 and otoliths and microtags were removed from tagged bass. Of 36 age-1 and older tagged bass recovered, 50% had no discernible otolith rings (read as age 0). Observed ages of all otoliths agreed with true ages only 14% of the time, and often differed by...