Nursery area characteristics of pleuronectids in coastal Alaska, USA

Juveniles of four species of pleuronectid flatfishes were abundant in bays and nearshore areas around Kodiak Island, Alaska during August 1991. Flatfish nursery areas located in deep water bays such as those surrounding Kodiak Island have not been previously reported. Age-0 rock sole (Pleuronectes bilineatus), flathead sole (Hippoglossoides elassodon), Pacific halibut (Hippoglossus stenolepis) and age-1 yellowfin sole (Pleuronectes asper) were collected close to one another and at first appeared to share nursery areas. Closer examination of associated within-bay distribution, depth, substrate, temperature and salinity data revealed characteristics which limited nursery area overlap. The major concentrations of juveniles of these species could usually be segregated by one or more of the physical parameters investigated. Based on the physical characteristics found to be most important in determining distribution of juveniles for each species, we hypothesize the following relationships. Age-0 rock sole are found predominantly in water depths less than 50 m, on sand or mixed sand substrate outside of or within bays. Age-0 flathead sole are found predominantly in water depths greater than 40 m, on mud or mixed mud substrate throughout bays. Age-0 Pacific halibut are found predominantly in water depths less than 40 m, on mixed sand substrate near or outside mouths of bays. Age-1 yellowfin sole are found predominantly in water depths less than 40 m, on mixed substrates at upper reaches of bays. These hypotheses will be field tested, after which the relationships may be considered for application to broader geographic areas.