EVALUATION OF SALT APPLICATION FOR HOLDING LARGEMOUTH BASS Micropterus salmoides FOR MARKETING AS A FOOD FISH

Small aquaculture producers have the ability to maintain fish as a live product and distribute fish in response to local market demand. Holding fish in live condition provides aquaculture producers and marketers the ability to constantly supply truly fresh fish to those customers who will accept nothing less than premium quality and are willing to pay for it.  The objective of this research is to investigate the methods for holding fish for market as live species that will allow vendors and distributors to minimize loss and manage risk. This research project evaluated use of salt in holding systems for marketing largemouth bass (Micropterus salmoides) as live food fish.  

Market size largemouth bass averaging 980 g each were held off feed 3 days prior to harvest. Thereafter fish were seined and hauled to a holding facility, and held in individual recirculating aquaculture systems (RAS) without feed for a period of 8 days. Two treatments were evaluated 1) control, 2) salt (NaCl) at 4 ppt.  Water quality was monitored daily, and blood chemistry was analyzed at 0, 48, 96, 144, and 192 hours after stocking to RAS. Blood chemistry was measured with the Abaxis Vetscan VS2 analyzer.

There was no mortality or apparent weight loss throughout the experiment. Water quality remained within acceptable parameters in both treatments. Fish transferred from the hauling tank to RAS system were designated as 0 h group and were also documented to exhibit stress. From time 0 h, blood parameters -albumin, and total protein increased and stabilized at 48 -96 h, whereas glucose decreased at 48 h and remained lower thereafter.  A reducing trend of alanine aminotransferase, bilirubin, and phosphate over time was recorded. Principal Component Analysis  (PCA) revealed a prominent effect of 4 ppt typically at 48 h and 96 h for [Na⁺], [Ca⁺⁺] and globulin (Fig 2). Cortisol level will be quantified for correlating the stress level with bio-chemical responses associated with the experimental groups.