Richard L. Noble

Radio-telemetry was used to evaluate the movements of 11 adult largemouth bass {Micropterus salmoides) from November 1995 through May 1996. A significant offshore migration occurred during the day throughout much of the winter. Seasonally, fish shifted offshore during cold water temperatures; a significant inverse correlation existed between distance offshore and water temperature. During high water levels some fish moved inshore to use inundated terrestrial habitat, even at water temperatures as low as 6 C. Although fish tended to move less during colder weather, most fish remained active...

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...

Florida largemouth bass (Micropterus salmoides floridanus) have been stocked extensively into Texas reservoirs containing the northern largemouth bass (M. s. salmoides) subspecies, and knowledge of the genetic make-up of these potentially intergraded populations is important to their continued management. Bass populations from 19 such reservoirs were analyzed by electrophoretic determination of individual fish genotypes. As measured by variation at 3 loci, intergradation ranged from 2% to 92%. Variations in percent intergradation among reservoirs were related to individual reservoir...

Food habits of gizzard shad (Dorosoma cepedianum), threadfin shad (D. petenense), and blue tilapia (Tilapia aurea) were studied in summer and winter, 1975. Stomach contents of all 3 species consisted predominantly of organic detritus, followed by green algae, blue-green algae and diatoms. Occurrence of planktonic foods corresponded closely with the composition of the plankton. Although food habits differed between season, they were closely correlated among species within season. Similarities in food habits of the 3 planktivorous species suggest potential food competition.

Scales from blue tilapia (Tilapia aurea) captured in gillnets indicated that annulus formation occurred primarily in March and April in 1973 and 1974, but in April and May 1975,. Average back-calculated total lengths of males were 197 and 258 mm at Age I and II and for females 183 and 248 mm. Total population of blue tilapia in December 1974 was estimated as 4,856,963. Of this total 3,120,810 were Age 0 and 1,591,823 were Age I. Biomass of the tilapia population was estimated to be 799,978 kg or 2,640 kg/ha. Survival of blue tilapia from Age I to II was calculated to be 7%. From these...

In the presence of a dense population of blue tilapia, the population of northern largemouth bass declined in three years to one-third its 1972 abundance in Trinidad Lake, Texas. A pond experiment with Florida largemouth bass indicated that bass failed to reproduce sllccessfully at a tilapia density of 2000 Ib/A, but at 1000 Ib/A some bass spawning occurred. Trends in gonosomatic indices suggest that eggs were retained by bass at high tilapia densities.