|Wills, Paul -|
Submitted to: Book of Abstracts Aquaculture America
Publication Type: Abstract Only
Publication Acceptance Date: October 20, 2010
Publication Date: February 28, 2011
Citation: Wills, P.S., Riche, M.A., Pfeiffer, T.J. 2011. Recovery of market size Florida pompano, grown at 3 ppt salinity, from the effects of severe osmotic stress after increasing salinity to 12 ppt [abstract]. Book of Abstracts Aquaculture America. p.490. Technical Abstract: Culturing a saltwater fish, such as Florida pompano Trachinotus carolinus, in near freshwater can lead to physiological changes that lead to slow growth, organ damage, and reduced survival. During a study to examine growth of pompano at different daily feed rates in low salinity (3 ppt) recirculating aquaculture systems (RAS), reduced growth and survival rates were noticed. The study was terminated early when the level of chronic mortalities had compromised the conclusions that could be draw from the study. A subsample of fish in each of the 16 culture tanks being used for the study (four tanks per RAS) were implanted with PIT tags, and a battery of physiological measurements taken to determine their status. In addition, carcass characteristics (e.g., weight, length, dress-out percentage, fillet moisture) were measured on a separate subsample of fish. The salinity of the culture water was then increased to 12 ppt to complete grow-out to market size (= 680 g) at which time the physiological measurements were made on up to five of the fish recovered with a PIT tag. Once again, carcass characteristic were measured on a subsample of fish. Condition (K) of the fish increased from 3.3 (SD=0.4) to 3.5 (SD=0.4) for the PIT tagged fish after the salinity was increased. Dress-out percentage (skin-off and pin bone removed) increased from 47.8% (SD=4.8) to 50.1% (SD=3.1), and fillet moisture decreased from 56.3% (SD=2.0) to 50.2% (SD=2.8). Daily percent mortality decreased markedly after the increase in salinity (Figure 1). The physiological data collected will aid in determining the requirements of pompano being reared at low salinities such that producers will be able to profitably grow pompano to market size. Figure 1. Mean daily mortality expressed as a percentage of the number of fish present in each replicate tank. The vertical dashed line indicates the day (1/26/2010) when the salinity reached the target of 12 ppt. Salinity was increased at ~ 2 ppt per day beginning 1/21/2010.