|The behavior, growth, and survival of witch flounder (Glyptocephalus cynoglossus) larvae in relation to prey availability: adaptions to an extended larval period|
Rabe, J.; Brown, J.A. (2001). The behavior, growth, and survival of witch flounder (Glyptocephalus cynoglossus) larvae in relation to prey availability: adaptions to an extended larval period. Fish. Bull. 99(3): 465-474
In: Fishery Bulletin. US Government Printing Office: Washington, D.C.. ISSN 0090-0656, more
Density; Sea; Size; Marine
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Foraging behavior and prey abundance are significant factors determining the survival success of fish during the larval stage. Witch flounder (Glyptocephalus cynoglossus) are reported to have the longest pelagic stage of any northwest Atlantic flatfish. We used laboratory experiments to investigate the behavior and performance of witch larvae in relation to prey availability during this important life history stage. In one experiment, larvae were reared at a range of prey densities (2000, 4000, and 8000 prey per liter) and their growth and survival were monitored for 12 weeks after hatching. In a second experiment the foraging behavior of larvae was recorded during feeding trials at a range of prey densities (250, 500, 1000, 2000, 4000, 8000, and 16,000 prey per liter) during weeks 2-8 after hatching. The larval search strategy for prey appeared to change from one that was saltatory to one that was cruising, and the foraging behavior was not strongly affected by variation in prey availability. The growth rate was rapid (0.53 mm-d) and was unaffected by changes in prey density as was survival. Witch flounder larvae likely have low prey requirements compared with yellowtail flounder and Atlantic cod reared under similar laboratory conditions The ability to forage effectively when prey is abundant or scarce and the low prey requirements of this species may be an adaptive response to the extended larval period.