8-10
Optimizing Early Life Stage Culture of Gamefish Species
Angie Hengst
,
University of Maryland Center for Environmental Science Horn Point Laboratory, Cambridge, MD
Brian Richardson
,
Fisheries Service, Maryland Department of Natural Resources, Oxford, MD
Dave Sien
,
Fisheries Service, Maryland Department of Natural Resources, Brandywine, MD
Erin L. Markin
,
University of Maryland Center for Environmental Science Horn Point Laboratory, Cambridge, MD
Reducing mortality and increasing production is a primary concern of hatchery managers in gamefish culture. Cannibalism and poor conversion to commercial food are two main causes of reduced production. In Maryland state hatcheries largemouth bass larvae (
Micropterus salmoides) have been difficult to convert to commercial feed from live food. Preliminary studies showed that by using a feeding regime of decapsulated artemia or krill meal mixed with increasing ratios of commercial feed over a four week period largemouth bass were successfully converted to a 100% commercial diet. Additional studies were conducted to examine the difference in commercial feed acceptance and growth rate between different size cohorts. Weights and lengths were measured weekly to determine growth rates and overall survival rates calculated.
In hatchery culture systems cannibalism in larval gamefish is a difficult problem to overcome. Tiger muskie (Esox Masquinongy X Esox Lucius) and walleye (Sander vitreus) are known to be cannibalistic in the wild as well as in culture. By adjusting tank variables in culture (water depth, tank color, light intensity and water clarity) we tested the ability to reduce cannibalism in tiger muskie and walleye larvae. Experiments were carried out in a factorial design with three replicates. For each variable and variable combination overall survival rate for each species was determined.
The results from this study will provide hatchery managers with practical ways to reduce cannibalism in gamefish species resulting in increased hatchery production. In addition, information gained from the feed conversion experiments will allow hatchery managers to start feed conversion at the optimum size for acceptance and growth. Together, this information will provide hatcheries with the necessary tools to increase overall production of gamefish species.
