3301

• UCREFRP Catalog Number: 3301
• Author: Papoulias, D.
• Title: Effect of Food Availability on Growth and Mortality of Larval Razorback Sucker,
• USFW Year: n.d.
• Copyright Material: NO

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larvae were largest (23.2 mm TL) when fed from 5 days after
hatching and smallest (15.8 mm TL) when fed beginning 29 days
after hatching (Table 1; Fig. 6; Appendix B).
Experiment 3. Mortality was greatest, but not significantly
different (.1>p>.05), when larvae were fed concentrations of 5 or
10 nauplii per liter. Larvae fed 50, 100, 500, and 1,000 nauplii
per liter had < 20k mortality, with no significant differences
(.1>p>.05) among treatments (Table 2; Fig. 7; Appendix C).
Mortalities leveled off when numbers of deaths resulted in food
concentrations available to survivors of 10-20 nauplii per fish
in 5 and 10 nauplii-per-liter treatments (Fig. 8; Appendix C).
Larval deaths were mostly between days 20 and 30 (Fig. 9;
Appendix C) at a mean TL of 10.1±1.2 mm (Fig. 10; Appendix C).
Surviving larvae fed at concentrations of 5, 10 and 50 nauplii
per liter did not differ in mean TL at end of the experiment
(14.9±.9 mm, 13.6±2.1 mm and 16.1±1.8 mm, respectively). Fish
fed 500 and 1000 nauplii were larger, at 25.0±2.9 mm and 23.8±3.4
mm, but did not differ significantly between one another (Table
2; Fig. 11; Appendix C).
Days to yolk sac absorption in razorback sucker, which were
not specifically identified in my experiments, is at about 7 days
post-hatch (Minckley and Gustafson, 1982). In my fish, yolk was
present at 5 days and at 8 days 2/3 of the fish were feeding.