Feeding regime has little impact on fatty acid composition and weight loss of hybrid crappie, Pomoxis nigromaculatus x Pomoxis annularis, and redear sunfish, Lepomis microlophus, at low (winter) water temperatures

Authors: ROY, LUKE - University Of Arkansas At Pine Bluff; Rawles, Steven - Steve; KELLY, ANITA - University Of Arkansas At Pine Bluff; STONE, NATHAN - University Of Arkansas At Pine Bluff; HAUKENES, ALF - University Of Arkansas At Pine Bluff; Webster, Carl

Submitted to: North American Journal of Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/30/2018
Publication Date: 4/14/2019
Publication URL: https://handle.nal.usda.gov/10113/6753473
Citation: Roy, L., Rawles, S.D., Kelly, A., Stone, N., Haukenes, A., Webster, C.D. 2019. Feeding regime has little impact on fatty acid composition and weight loss of hybrid crappie, Pomoxis nigromaculatus x Pomoxis annularis, and redear sunfish, Lepomis microlophus, at low (winter) water temperatures. North American Journal of Aquaculture. 81(2):140-152. https://doi.org/10.1002/naaq.10081.
DOI: https://doi.org/10.1002/naaq.10081

Interpretive Summary: Winter mortality is a common problem for producers in temperate regions of the United States. Sportfish, such as hybrid crappie and redear sunfish are popular among recreational anglers and are produced by either commercial aquaculture facilities or Federal/state hatcheries. Winter feeding programs have been suggested as a potential avenue to improve survival, condition, and reduce weight loss of cultured fish during the winter. Methods of winter feeding vary widely among farms, and currently there are no recognized best management practices for winter feeding. The impact of different winter-feeding regimes on survival, growth, and fatty acid composition of hybrid crappie and redear sunfish were evaluated in temperature-controlled aquarium systems. Hybrid crappie (4 g) and redear sunfish (1 g) were stocked at ambient water temperature after which, temperature was reduced over the course of 7 d to mimic winter water temperatures in the southeastern U.S. (45 F). Fish were fed blood worms using one of three feeding regimes that included feeding fish all they would eat twice per week (TPW, 2), once per week (OPW, 1), or once per month (OPM, M). Following 13-wks of culture, there were no differences among treatments in final weight, survival, weight loss, or specific growth rate for either species. Hybrid crappie lost 27-29% of their initial body weight, while redear sunfish lost more than 30% of their initial body weight. Fatty acid composition of both species differed among treatments, generally showing a decline in saturated fatty acids, and static/increase in highly unsaturated fatty acids. Results suggest that feeding regime has little effect on weight gain in hybrid crappie and redear sunfish when fed at colder (<9 C) water temperatures; however, this did not affect survival.

Technical Abstract: Winter mortality is a common problem for producers in temperate regions of the United States. Sportfish, such as hybrid crappie, Pomoxis nigromaculatus x Pomoxis annularis, and redear sunfish, Lepomis microlophus, are popular among recreational anglers and are produced by either commercial aquaculture facilities or Federal/state hatcheries. Winter feeding programs have been suggested as a potential avenue to improve survival, condition, and reduce weight loss of cultured fish during the winter. Methods of winter feeding vary widely among farms, and currently there are no recognized best management practices for winter feeding. The impact of different winter-feeding regimes on survival, growth, and fatty acid composition of hybrid crappie and redear sunfish were evaluated in temperature-controlled aquarium systems. Hybrid crappie (mean +/- SD; 3.50 +/- 0.19 g) and redear sunfish (1.35 +/- 0.10 g) were stocked at ambient water temperature after which, temperature was reduced to 6 deg C or 8C, respectively, over the course of 7 d to mimic winter conditions. Three feeding regimes were implemented (3 tanks/regime) that included ad libitum feeding twice per week (TPW, 2), once per week (OPW, 1), or once per month (OPM, M) on blood worms. Following 13-wks of culture, there were no differences (P > 0.05) among treatments in final weight, survival, weight loss, or specific growth rate for either species. Hybrid crappie lost 27-29% of their initial body weight, while redear sunfish lost more than 30% of their initial body weight. Fatty acid composition of both species differed significantly (P < 0.05) among treatments generally showing a decline in saturates from initial fish levels, and static/increase in highly unsaturated fatty acids. Results suggest that feeding regime has little effect on weight gain in hybrid crappie and redear sunfish when fed at colder (<9 C) water temperatures; however, this did not adversely affect survival.