Researchers assess predation of hatchery-cultured juvenile red king crabs in the wild
A juvenile red king crab, 3.5 mm carapace width, was tethered at 10 m depth in southern Lynn Canal near Juneau. Photo by Ginny Eckert.Ben Daly did field experiments with hatchery-cultured juvenile red king crabs as part of his Ph.D. research at the University of Alaska Fairbanks. Daly and UCLA undergraduate researcher Timothy White tethered small (1.8–4.0 mm carapace width) crabs for 24-hour trials during July and September 2011 in southern Lynn Canal near Juneau, and used scuba and underwater video cameras to assess survival and predator interactions. Daly identified hermit crabs, Alaskan ronquil, arctic shanny, northern rock sole, and kelp greenling as predators and found that survival did not vary by body size or deployment month. Time until mortal attack was longer for larger crabs compared to small crabs and most mortal attacks occurred in daylight hours.
Predation will likely be the greatest ecological hurdle for hatchery-cultured juveniles in the wild; however, information on predation of red king crab juveniles in nearshore habitats remains scarce. This research is an important first step in developing release strategies and suggests predation pressure should be considered when selecting release time and location.
The link below shows video of a hermit crab and greenling preying on a tethered juvenile red king crab.
News Flash is edited by Ben Daly. AKCRRAB is a research and rehabilitation project sponsored by the Alaska Sea Grant College Program, UAF School of Fisheries and Ocean Sciences, NOAA Fisheries, the Alutiiq Pride Shellfish Hatchery, community groups, and industry members.
