8142

• UCREFRP Catalog Number: 8142
• Author: Horn, M. J.
• Title: Nutritional Limitation of Recruitment in the Razorback Sucker ‎(
• USFW Year: 1996.
• Copyright Material: NO

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25

in turn to estimate feeding rates. Once feeding commenced, excess food and feces were

siphoned and half the volume in each tank was replaced with aged tap water daily.

c. Experimental Protocols.

. Similar protocols were followed for each experiment. 250 larvae were transferred

to 30 L of aged water in each 38-L tank and allowed to acclimate for 24 hr prior to

beginning. Larvae dying in this period, presumably from handling stress or pipetting

injury, were replaced.

Experiments I (lipids) and IT (growth) in 1992 were performed at water

temperatures of 14 :t IOC and 23 :t IOC , respectively. Experiment ill, again for lipids and

growth and also for morphology and histology in 1993, was at 18:t IOC. In 1995, larvae

were reared at 18 :t IOC to ascertain otolith formation and growth (Experiment IV). Three.

treatments were applied (in all but otolith studies where the second was omitted) as

follows: 1) Starved, all food was withheld; 2) Suboptimal, approximating a

"maintenance" level; and 3) Ad libitum. Each treatment was replicated 3 times, and food

was provided (if appropriate) 3 times a day.

In the Starved treatment no food was supplied and dead and dying larvae were

removed immediately after discovery to preclude cannibalism or carrion feeding (neither

of which were observed). The Suboptimal treatment involved a food level of 4-6

naupliHarva-l.feeding-1 (15 naupliHarva-l.d-I), the minimum ration necessary for

maintenance estimated by Papoulias (1988). Feeding Ad libitum was at a level of 120

. naupliHarva-l.feeding-1 (360 nauplii.larva-I.d-I).