Submitted to: Journal of Applied Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2000
Publication Date: 6/1/2001
Citation: LUDWIG, G.M., LOCHMANN, S. CULTURE OF SUNSHINE BASS MORONE CHRYSOPS X M. SAXATILIS, FRY IN TANKS WITH ZOOPLANKTON CROPPED FROM PONDS WITH A DRUM FILTER. JOURNAL OF APPLIED AQUACULTURE. 2001. v.10(2). p.11-26. Interpretive Summary: Culture of fish fry in tanks instead of ponds enables farmers to monitor fry health and survival and to maintain an optimum aquatic environment for growth. However, some fish such as sunshine bass a hybrid between white and striped bass require live rotifers tiny zooplankton for their first food. Rotifers are abundant in ponds at certain times. This research found that ponds could be managed in a way that would maximize the amount of rotifers and other small zooplankton at the time it was needed to feed small fish fry. The zooplankton was harvested with a drum filter and fed for 21 days at three different rates to sunshine bass fry stocked into tanks where they also received microencapsulated fry feed. The research found that the fry that received the most feed survived at the highest rates, 24.3%. However, fry with the highest survival rates grew slower than those in tanks that received less food but had lower survival rates.
Technical Abstract: Sunshine bass, Morone chrysops X C. saxatilis, fry were stocked into 260 L tanks at age 4 days at 20/L and harvested 21 days later. Zooplankton collected with a drum filter from ponds managed to maximize rotifer densities at the time of filtration were fed to the fry at rates of 10, 20, or 30 zooplankton/mL once per day with three replicates of each treatment. The zooplankton were retained by a 60 um filter. The fry also received microencapsulated, 50% protein fry feed at 1 g/2.4 hr. At harvest, mean survival rates of 3.31%, 14.2%, and 23.3% varied directly with zooplankton feeding rates. Fry from the 30 zooplankton/mL treatment survived at a significantly higher rate than fry from the 10 zooplankton/mL treatment. Average total lengths of fry, 8.24 mm, 8.15mm, and 7.66 mm, were inversely reltated to survival with fry from the 30 zooplankton/mL treatment being significantly smaller than fry from the other treatments. The experiment showed that fry could be raised in tanks with zooplankton harvested from ponds with a drum filter.