161 Netherlands Journal of Sea Research 34 (1-3): 161-175 (1995) NURSERY AREA CHARACTERISTICS OF PLEURONECTIDS IN COASTAL ALASKA, USA* BRENDA L. NORCROSS, BRENDA A. HOLLADAY and FRANZ J. MOTER Institute of Marine Science, University of Alaska Fairbanks, Fairbanks, Alaska 99775-1080 USA ABSTRACT 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 aspet) were collected close to one another and at first appeared to share nursery areas. Closer examination of associated within-bay distribution, depth, substrate, tem- perature and salinity data revealed characteristics which limited nursery area overlap. The major con- centrations 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 deter- mining 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 appli- cation to broader geographic areas. Key words: Pleuronectidae, nursery area, discriminant analysis, Alaska 1. INTRODUCTION Populations of twelve species of potentially competi- tive pleuronectids are found near Kodiak Island, Alaska (Rogers et aL, 1986). The prime targets for commercial fisheries are Pacific halibut (Hippoglos- sus stenolepis), flathead sole ( Hippoglossoides elas- sodon), rock sole (Pleuronectes bilineatus), rex sole ( Errex zachirus) and Dover sole (Microstomus pacifi- cus). There are also directed fisheries for English sole (Pleuronectes vetulus) and starry flounder (Platich- thys stellatus). By-catch includes yellowfin sole (Pleu- ronectes asper), Alaska plaice ( Pleuronectes quadrituberculatus), butter sole (Pleuronectes iso- lepis), and sand sole (Psettichthys rnelanostictus), which are marketed secondarily. An attempt is cur- rently underway to develop a fishery for arrowtooth flounder (Atheresthes stomias) for surimi, or fish paste. Despite their strong economic importance, knowledge of the early life history of flatfishes and their habitat in Alaska is minimal. Inferences about the life history of juvenile flatfishes must be made from studies of the same species along the coasts of Oregon and Washington, or from related species in other parts of the world. Shallow coastal areas, protected bays and estuar- ies are often considered vital as nursery areas for certain species of flatfish. Tidal flats behind barrier islands are prime nursery areas for North Sea plaice (Pleuronectes platessa) (Kuipers, 1977), southern flounder (Paralichthys lethostigma) and summer flounder (Paralichthys dentatus) (Burke et aL, 1991). Sheltered beaches are nursery grounds for sole (Solea solea) (Riley et al., 1981), common dab *Contribution No. 1517 Institute of Marine Science