504 
Abstract .—Juveniles of four species 
of pleuronectid flatfishes were abun- 
dant in bays and nearshore areas 
around Kodiak Island, Alaska, during 
August 1991 and 1992. The four most 
abundant species of juvenile (age-0 or 
age- 1) flatfishes were rock sole ( Pleuro - 
nectes bilineatus), flathead sole (Hip- 
poglossoides elassodon ), Pacific halibut 
( Hippoglossus stenolepis), and yellow- 
fin sole ( Pleuronectes asper ). These spe- 
cies appeared to share nursery areas; 
however, physical characteristics of the 
nursery areas occupied by each species 
limited the amount of true overlap 
among species. Tree-based regression 
of catch-per-unit-of-effort data on 
physical parameters was used to refine 
conceptual models of species distribu- 
tion, which were originally based only 
on 1991 data. 
Threshold values of the physical pa- 
rameters were specified that best dis- 
criminated among stations with differ- 
ent abundances. Highest abundances of 
age-0 rock sole were found on sand or 
muddy sand at temperatures greater 
than 8.7°C, as well as on other mixed 
sand stations less than 28 m deep. Age- 
0 flathead sole were most abundant at 
temperatures less than 8.9°C and on 
mixed mud substrates. At warmer tem- 
peratures, abundances were high only 
if the depth was greater than 48 m, re- 
gardless of sediment type. Age-0 Pacific 
halibut were most abundant in depths 
less than 40 m at sites more than 2.9 
km outside the mouths of bays. Inside 
bays, halibut were found in lower abun- 
dances in water over 9.0°C and on sedi- 
ments containing both sand and mud. 
Age-1 yellowfin sole were always found 
in depths less than 28 m on mixed mud 
substrates. They were usually found 
within bays, with highest abundances 
at heads of large bays more than 32 km 
from the bay mouth. These four most 
abundant flatfishes therefore appeared 
to partition the available habitat in ways 
that minimized resource competition. 
Manuscript accepted 26 February 1997 
Fishery Bulletin 95:504-520 (1997). 
Habitat models for 
juvenile pleuronectids 
around Kodiak Island, Alaska* 
Brenda L. Norcross** 
Franz-Josef Muter 
Brenda A. Holfaday 
Institute of Marine Science 
School of Fisheries and Ocean Sciences 
University of Alaska Fairbanks 
Fairbanks, Alaska 99775-7220 
**E-mail address: norcross@ims.alaska.edu 
In the Gulf of Alaska, there are di- 
rected fisheries for deep-water and 
shallow-water complexes of fishes. 
The deep-water complex is made up 
of rex sole ( Errex zachirus), Dover 
sole ( Microstomus pacificus), Green- 
land halibut ( Reinhardtius hippo- 
glossoides), arrowtooth flounder 
(Atherestes stomias ), and rockfishes 
( Sebastes spp.). The shallow water 
complex incorporates all other flat- 
fishes found in the area, including 
rock sole ( Pleuronectes bilineatus), 
flathead sole ( Hippoglossoides 
elassodon), yellowfin sole ( Pleuro- 
nectes asper), English sole (Pleuro- 
nectes vetulus), starry flounder 
( Platichthys stellatus), Alaska pla- 
ice (Pleuronectes quadritubercu- 
latus), butter sole ( Pleuronectes 
isolepis), and sand sole (Psettichthys 
melanostictus), in addition to Pacific 
cod ( Gadus macrocephalus) and 
walleye pollock (Theragra chalco- 
gramma). The groundfish harvest 
from the Gulf of Alaska has been 
over 190,000 metric tons (t) annu- 
ally from 1990 through 1995, for a 
total of 1,320,000 t, not including 
Pacific halibut (Hippoglossus steno- 
lepis) or discards. Of that, in 1995, 
716,000 t were landed in Kodiak, 
Alaska, for a value of $34 million 
(NMFS, Fisheries Management 
Biv., P.O. Box 21668, Juneau, AK 
99802-1668). When Pacific halibut, 
a species regulated separately from 
other groundfishes, is included, the 
total landed at Kodiak in 1995 was 
75,000 t at $49 million. Although 
rockfishes (Carlson and Straty, 
1981; Krieger, 1992, 1993), cod 
(Wespestad et al., 1986; Dunn and 
Matarese, 1987), and pollock ( Janusz, 
1986; Dunn and Matarese, 1987; 
Kendall et al., 1994; Muter and 
Norcross, 1994; Swartzman et al., 
1994) have been studied in the Gulf 
of Alaska, very little is known about 
flatfishes (Parker, 1989; Moles and 
Norcross, 1995). The large abun- 
dance and value of these commer- 
cially important flatfishes and lack 
of knowledge of their early life his- 
tory led us to investigate distribu- 
tion of juvenile flatfishes around 
Kodiak Island. 
In general, recently metamor- 
phosed flatfishes recruit to shallow, 
nearshore nursery areas with fine- 
grained sediments (Edwards and 
Steele, 1968; Gibson, 1973; Toole, 
1980; Hogue and Carey, 1982; de 
Ben et al., 1990). Intertidal zones, 
estuaries, and shallow protected 
bays are nursery areas for flatfishes 
in the continental United States 
(Krygier and Pearcy, 1986; Allen, 
1988; Rogers et al., 1988; Wyanski, 
1990), Canada (Tyler, 1971), Europe 
* Contribution 1627, Institute of Marine Sci- 
ence, University of Alaska, Fairbanks, 
Alaska 99775-7220. 
