Behavior, Growth and Habitat Selection of Hatchery Esocids Reared with Artificial Vegetation

Abstract

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.

Positive welfare effects of physical enrichments from the nature-, functions- and feeling- based approaches in farmed rainbow trout (Oncorhynchus mykiss)

“…They were split in two experimental treatments: an enriched environment (E) and a barren environment (B). The enriched environment was composed by PVC pipes, plastic plants (grapes of leaves) and white stones (number and size of each structure are given in Table 1), representing a complete panel of the different structures tested in the literature reviewed by Naslund and Johnsson (2016): pipes as shelters to provide hiding places and to limit aggression in salmons (Naslund et al, 2013); artificial vegetation as shelters but also as a manner to complexify the environment, which reduces startling responses in pike (Esox masquinongy) (Einfalt et al, 2013); stones as landmarks to complexify the environment and promote behavioral flexibility and better adaptation in case of threatening situations in salmons (Salvanes et al, 2013). Floor covering was estimated by using photographs of the tanks (with a known surface), where each structure was superposed by a corresponding geometrical shape which surface was known.…”

Environmental enrichment for fish in captive environments: effects of physical structures and substrates

“…(Esocidae) (Einfalt et al . ) and also reduce adaptation time to experimental conditions and shoaling behaviour in common bream Abramis brama (Cyprinidae) (Gerasimov and Stolbunov ). In Atlantic cod, EE leads to reduced swimming activity and more context‐dependent variability in shoaling (Salvanes and Braithwaite ; Salvanes et al .…”

“…), pikes (Einfalt et al . ) and sleepy cod Oxyeleotris lineolata (Eleotridae) (Herbert et al . ), although the latter species did increase in condition factor when shelters were present.…”

Effects of artificial submersed vegetation on consumption and growth of mandarin fish Siniperca chuatsi (Basilewsky) foraging on live prey

“…Contrary to the results of the present study, the growth rate of the piscivorous perch (Perca Fluviatilis Linneaus) and juvenile pinfish (Lagodon rhomboids Linneaus) decreased with increased refuge efficiency, as complex habitat protected prey from predators, and in turn, increased the capture time and foraging energetic cost of predators (Diehl 1993;Persson and Eklov 1995;Spitzer et al 2000). In another study, vegetation decreased the startle and crowding stress for Tiger Muskellunge (Muskellunge Esox masquinongy Mitchill  Northern Pike E. lucius Linneaus), but growth was not significantly different between non-vegetated and semi-vegetated treatments (Einfalt et al 2013).…”