FIRST-YEAR CONTRIBUTION TO THE YEAR CLASS AND GROWTH OF LARGEMOUTH BASS STOCKED AT 50 MM AND 100 MM INTO THE ARKANSAS RIVER
 

N. Elizabeth Heitman, Christopher L. Racey, and Steve E. Lochmann

 Student next to electrofishing boat
 
Student holing large mouth bassFew evaluations of largemouth bass stockings have been conducted in rivers. Oxytetracycline-marked largemouth bass Micropterus salmoides, averaging 50 or 100 mm TL, were stocked into backwater areas of pool 4 of the Arkansas River, in the summer of 2003, at densities of 309 and 62 fish/ha, respectively. Contributions to the year class of 50-mm (13.2%) and 100-mm (13.8%) stocked largemouth bass were not significantly different in fall 2003. Stocking contributions of 50-mm (17.6%) and 100-mm (17.2%) largemouth bass were also not significantly different in spring 2004. Contributions were not significantly different between seasons. Mean (SD) total lengths for 50-mm stocked, 100-mm stocked, and wild fish were 164 (38), 172 (39), and 162 (43) mm, respectively, in fall 2003, and 187 (37), 185 (43), and 179 (44) mm, respectively in spring 2004. There were no significant differences among mean lengths for stocked or wild fish in either season. Stocking five times as many 50-mm as 100-mm largemouth bass yielded similar contributions. Largemouth bass stocked into the Arkansas River had one-year stocking contributions similar to largemouth bass stocked into reservoirs and lakes.
 

VARIABILITY IN EGG CHARACTERISTICS AMONG WHITE BASS AND THE EGG VOLUME:LARVAL STANDARD LENGTH RELATION IN SUNSHINE BASS

Steve E. Lochmann*, Christopher L. Racey, Kelly J. Goodwin, and Christopher C. Green

 Sunshine Bass
 
Student working with sunshine bass eggsBesides fast growth or favorable feed conversion, selection of white bass Morone chrysops brood stock could be based on favorable egg or fry characteristics. Eggs from 12 white bass, used to produce sunshine bass fry, were individually photographed and incubated. Average egg volume ranged from 0.316 to 0.422 mm3 and varied significantly among females (P<0.0001). Hatch rates ranged from 49% to 96%, but there was no relationship between hatch rate and egg volume. Total lipids varied from 4.03% to 6.17%, and n-3 HUFAs comprised more than 3% of lipids in eggs from all females. There was no relationship between egg volume and lipid levels. Yolk-sac fry were also photographed within 3 h of hatching. Standard lengths of yolk-sac fry were less variable than egg volumes (CV=6.3%) and ranged from 2.35 to 3.62 mm. Average standard length ranged from 2.89 to 3.08 mm and also varied among females (P<0.0001). Specific female and time to hatch explained 60% of the variability in yolk-sac fry SL. Some females had egg and fry characteristics more suitable to increasing survival and fingerling production. Selection for these characteristics in brood stock white bass females could lead to improved production of sunshine bass fingerlings.
 

MATERNAL AND TEMPERATURE INFLUENCES ON PERCENT HATCH AND TOTAL LENGTH AT HATCH OF SUNSHINE BASS

Steve E. Lochmann, Kelly J. Goodwin, and Christopher L. Racey

 Wet Lab
 
Sunshine Bass LarvaeWe examined the relation between temperature and egg stage duration, and tested the hypothesis that a longer egg stage would produce a larger larvae. We examined the relation between temperature and percent hatch. Finally, we tested the hypothesis that maternal genetic influences were greater than temperature effects on size at hatch and percent hatch. Eggs from female white bass Morone chrysops were fertilized by a single, but different male striped bass M. saxatilis each week for four weeks. Approximately 4000 eggs from each female were hatched at 14, 16, 18, and 20 oC. Yolk-sac larvae were removed from the jars, photographed individually, and enumerated. Eggs incubated at a cooler temperature took longer to hatch, but larvae were significantly larger at hatch. Temperature did not influence percent hatch. The maternal influence on length at hatch appeared to be greater than the temperature influence on length at hatch. There was an interaction between maternal influence and temperature. Larvae from some females exhibited a monotonically decreasing length at hatch as temperature increased. Larvae from other females exhibited a non-linear response to temperature, with larvae significantly larger at hatch at the lowest and highest temperatures and smaller at intermediate temperatures.
 
 

SUNSHINE BASS FINGERLING TANK CULTURE: EFFECTS OF TANK STOCKING DENSITIES ON GROWTH AND SURVIVAL.

Gerald M. Ludwig and Steve E. Lochmann

 Fingerling Tanks
 
Research Associate working with Tank Stocking DensitiesDetermining the optimum parameters for tank culture of sunshine bass fingerlings will facilitate a year-round supply of seed for the production cycle of this increasingly popular food fish. This experiment determined the relationship between the stocking density of sunshine bass larvae into tanks and their survival rate and size at the time they had become trained to accept commercial feeds. Four-day post-hatch (dph) larvae were stocked at 10 densities from 30 to 120 larvae.L-1 at 10 larvae.L-1 increments. The larvae were initially fed rotifers cultured with Nannochloropsis sp. algae paste and commercial rotifer feed until 10 dph. Conversion to Artemia began at 7 dph and training to dry starter feed began at 20 dph. Photographs of live samples of larvae taken at 4 dph and harvest were used to determine length and depth of the fish. Regression analysis determined no significant relationship between survival and stocking density. Length and weight of the fish had a linear, negative relationship with stocking density, while total tank yield had a curvilinear relationship with stocking density. The stocking density that provided maximum yield was 85.6 larvae.L-1. Based on prices of larvae and fingerlings, maximum value was realized when larvae were stocked at 115 larvae.L-1.