Behaviour, growth and habitat selection of hatchery esocids reared with artificial vegetation

We evaluated the effect of adding artificial vegetation to the rearing environment on behavior, habitat selection, and growth of hatchery esocids in laboratory experiments. First, Muskellunge (Esox masquinongy) and the hybrid Tiger Muskellunge (Muskellunge × Northern Pike E. lucius ) resided separately in pools either with or without artificial vegetation (250 stems/m2) for 2 weeks. Both taxa raised in vegetated pools dispersed and spent more time away from the sides of the pools than did individuals residing in open pools. Tiger Muskellunge in vegetated pools also startled less often than fish in open pools, whereas vegetation did not decrease Muskellunge startle behavior. We next examined habitat selection between esocids raised in tanks with and without vegetation. Fish were tested in semivegetated pools, and for Tiger Muskellunge acclimated in vegetation, more fish (80%) used the vegetated half of the pool compared with fish raised in open tanks (61%). Muskellunge, regardless of treatment, spent a high proportion (>90%) of time in vegetation. Finally, growth of both taxa was similar between esocids reared in vegetated tanks compared with esocids reared in open tanks. The presence of artificial vegetation in tanks caused changes in behavior for both esocid taxa, but Tiger Muskellunge were more flexible in modifying their behavior. Behavioral responses resulting from exposure to vegetation could increase survival after stocking in lakes.