|ROY, LUKE - Auburn University|
|Rawles, Steven - Steve|
|KELLY, ANITA - University Of Arkansas At Pine Bluff|
|STONE, NATHAN - University Of Arkansas At Pine Bluff|
|PARK, JEONGHWAN - University Of Arkansas At Pine Bluff|
Submitted to: North American Journal of Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/14/2019
Publication Date: 3/23/2019
Citation: Roy, L., Rawles, S.D., Kelly, A., Stone, N., Park, J., Webster, C.D. 2019. The effects of different winter feeding regimens on growth, survival, and fatty acid composition of fathead minnow and golden shiners. North American Journal of Aquaculture. 81:189-200. https://doi.org/10.1002/naaq.10086.
Interpretive Summary: Winter mortality is a common problem for producers in temperate regions of the United States. Baitfish, such as fathead minnows and golden shiners, are popular among recreational anglers where they are preferred for use to catch sportfish, such as largemouth bass, and are produced by commercial aquaculture facilities. 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 fathead minnows and golden shiners were evaluated in temperature-controlled aquarium systems. Both species of fish were stocked in separate recirculating aquaculture systems at ambient water temperature after which, temperature was reduced over the course of 7 days to mimic winter water temperatures in the southeastern U.S. (45 F). Fish were fed a commercial diet using one of three feeding regimes that included feeding fish all they would eat twice per week, once per week, or once per month. Following 13-weeks of culture, there were differences between the two species regarding weight gain (loss), survival, and fatty acid composition. Fathead minnows fed twice per week had a 3% weight gain at the end of the study, while those fed less frequently lost weight. Golden shiners lost weight during the study no matter which feeding regime was used. Fatty acid profiles, an indicator of the nutritional status of fish, were also measured for both baitfish species and differed significantly among treatments, generally showing a decline in saturated fatty acids from initial fish levels, and an increase in polyunsaturated fatty acids as feeding frequency decreased. Results suggest that while fish may lose weight during the winter, it does not appear to adversely affect survival, while both species alter their fatty acid compositions to optimize omega-3 polyunsaturated fatty acids during cold water temperatures in order to better maintain cellular metabolism in winter. It does appear that feeding fathead minnows twice per week improves fish "heartiness" come Spring.
Technical Abstract: Winter mortality is a common problem for baitfish farmers in Arkansas that produce Fathead Minnows (FHM) Pimephales promelas and Golden Shiners (GS) Notemigonus crysoleucas. Winter feeding programs are a potential avenue to improve survival, condition, and reduce weight loss of baitfish during winter. Methods of winter feeding vary widely among baitfish farms and currently there are no recognized best management practices. The impact of different winter feeding regimes on FHM and GS survival, growth, and lipid storage were evaluated in temperature-controlled aquarium systems. FHM (mean +/- SD; 0.88 +/- 0.04 g) or GS (0.88 +/- 0.02 g) were stocked at ambient water temperature after which temperature was reduced to 6 deg C or 8 deg C, respectively, over the course of 7 d to mimic winter conditions. Three feeding regimes (35% protein commercial diet) were implemented (3 tanks/regime) that included ad libitum feeding twice per week (TPW), once per week (OPW), or once per month (OPM). Significant differences (P < or = 0.05) in weight gain, condition factor, and specific growth rate were observed after 13 wks. FHM fed TPW gained nearly 3%, while fish fed OPW or OPM lost weight (2.3 and 10.1%, respectively). There were no significant differences in GS final weight (0.79-0.82 g), survival (65.0-88.3%), or weight gain (-6.84 to -9.50%) among treatments after 12 wks. Condition factors of GS from the TPW treatment were significantly higher (P < or = 0.05) than those fed OPW or OPM. Fatty acid profiles of both baitfish species differed significantly (P < 0.05) among treatments generally showing a decline in saturated fatty acids from initial fish levels, and an increase in polyunsaturated fatty acids as feeding frequency decreased. Results suggest that while fish may lose weight during the winter, it does not appear to adversely affect survival, while both species alter their fatty acid compositions to optimize n-3 PUFA during cold water temperatures.