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United States Department of Agriculture

Agricultural Research Service

Title: Relative Triacylglycerol and Morphometric Measures of Condition in Sunshine Bass Fry.

Authors
item Lochmann, Steve - UAPB
item Ludwig, Gerald

Submitted to: North American Journal of Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 4, 2002
Publication Date: October 1, 2003
Citation: LOCHMANN, S., LUDWIG, G.M. RELATIVE TRIACYLGLYCEROL AND MORPHOMETRIC MEASURES OF CONDITION IN SUNSHINE BASS FRY. NORTH AMERICAN JOURNAL OF AQUACULTURE. 2003. v.65. pp.191-202

Interpretive Summary: Farmers culturing sunshine bass fingerlings stock fry into fertilized ponds and then wait for 6 weeks before the fish are harvested. Many factors can affect growth and survival of the fish during these times and sometimes survival may be so low that it would be better to drain the pond and start over. Unfortunately there are few ways that a farmer can predict the survival probabilities in culture ponds. On possibility is to determine collect fry and determine their physical or chemical condition. Fish that are in good physical condition, as indicated by morphological or chemical indices, presumably have higher chances of survival. This research measured at several combinations of body dimensions such as length and depth of the fish and several chemical conditions such as the composition of body fats soon after the fry were stocked into culture tanks. The qualitative and quantitative values of these measurements were then correlated with the amounts of feed that had been offered during the culture period. Morphometric chemical idices were found to be positively related to the amount of feed that had been offered during the culture period. Additional research is warranted to relate the indices to survival. Farmers culturing sunshine bass fingerlings stock fry into fertilized ponds and then wait for 6 weeks before the fish are harvested. Many factors can affect growth and survival of the fish during these times and sometimes survival may be so low that it would be better to drain the pond and start over. Unfortunately there are few ways that a farmer can predict the survival probabilities in culture ponds. On possibility is to determine collect fry and determine their physical or chemical condition. Fish that are in good physical condition, as indicated by morphological or chemical indices, presumably have higher chances of survival. This research measured at several combinations of body dimensions such as length and depth of the fish and several chemical conditions such as the composition of body fats soon after the fry were stocked into culture tanks. The qualitative and quantitative values of these measurements were then correlated with the amounts of feed that had been offered during the culture period. Morphometric chemical idices were found to be positively related to the amount of feed that had been offered during the culture period. Additional research is warranted to relate the indices to survival.

Technical Abstract: Condition measures are assessed for wild populations of fish fry to examine production and the implications for recruitment variability. These condition measures might guide management decisions in fish culture. We developed two condition measures, one based on morphometric measurements and one based on lipid class composition, for sunshine bass (Morone saxatilis X M. chrysops) fry. Prey concentrations were varied during three tank studies. Fry were sampled periodically and analyzed morphometrically and biochemically. Discriminant function analyses, using morphometrics and lipid class composition, were used to classify fry into treatment groups. The most successful discriminant function, based on morphometrics, misclassified only 25% of test fry. The discriminant function based on lipid class composition was less successful. We developed a condition measure based on relative triacylglycerol (TAG) content. Well-fed fry (15-20 prey/mL had significantly higher average relative TAG values during the third week of two studies. Undernourished fry had relative TAG values of approximately 0.5, while well-fed fry had values ranging from 1.0-5.0. Relative TAG and morphometric discriminant function might be used to guide management decisions during phase 1 fingerling production of sunshine bass.

Last Modified: 8/22/2014
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