Use of low-salinity water and gel-coating to minimize handling mortality of spot, Leiostomus xanthurus (Perciformes: Sciaenidae)

Capture, handling and transport of fish often result in mortality either from external injury or stress-induced disruption of normal physiology. Two methods were tested for reducing such mortality in juvenile spot, Leiostomus xanthurus. Salinity was reduced from ambient to 10 ppt by adding aged tapwater to reduce metabolic costs directly associated with salinity and resulted in improved survivorship of spot in all experiments. To reduce damage to fish epithelia from handling, the handler's hands were coated with a water-soluble gel. Results of the gel application were inconclusive, perhaps because no difference occurred in external damage to fish handled with water- or gel-covered hands, or chemical differences exist between the gel and fish mucus. Refinements in the salinity reduction method appear likely to increase survival, whereas future research with gel-coatings needs to employ compounds with properties similar to fish mucus.