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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density resulting in <50% mortality was between 10 and 50 nauplii
per liter. At 50 nauplii per liter, the fish were receiving
approximately 20 nauplii each at both beginning and end of the
experiment. In treatments where fish received 5 and 10 nauplii
per liter, mortalities during the experiment resulted in a range
of 10 to 20 nauplii per fish at termination. These surviving
fish grew as large as those receiving 20 nauplii per liter from
the outset, which may indicate that 10-20 nauplii per fish is a
minimum necessary for survival during the critical period.
Larval fish put energy from food directly into growth
(Blaxter, 1969). Rapid growth makes the fish less vulnerable to
predation, but perhaps more dependent on reliable exogenous food
supplies due to a lack of energy reserves (O'Connell and Raymond,
1970; Taylor and Freeberg, 1984). Fish in my experiments that
had been starved for different periods, but survived to take
advantage of food when finally offered, grew reasonably well.
Fish starved for 29 days achieved an average TL of 15.8±.9 mm
while those offered abundant food from the beginning grew to
23.2±2.3 mm. The same trend was seen for fish receiving
different amounts of food. Fish receiving 5 nauplii/l were
14.9+.9 mm TL and those at 500 and 1,000 nauplii/l were 25±2.9
and 23.7+3.4 mm TL. Fish that starved to death in absence of
food measurers 9.3+.7 to 9.6+.8 mm TL and those that died from
insufficient food measured 10.1+1.2 mm TL. It has been shown
that fish will resorb tissue and lose weight and perhaps length
when starved (Ivlev, 1961). Fish with no food were slightly