472 



Fishery Bulletin 103(3) 



N 57.70 



~ N 57.65 



M 52.55 



W 152.50 



W 152.45 



W 152 35 



W 152.30 



Longitude 



Figure 2 



Kalsin and Middle Bay sample sites (1991-96) and bathymetry. Fixed (sampled every year) 

 sites are noted. 



at the mouth of the bay, and encompasses an area of 

 34 km 2 . Rocky cliffs and islands surround the mouths 

 of the bays, and rocks in the sediment made several 

 areas untrawlable (Fig. 2). Although trawling was not 

 conducted in these areas, depth and sediment data were 

 collected. In this analysis, untrawlable areas were still 

 considered possible flatfish habitat and were included in 

 the measurements of the size of the total study area. 



Annual cruises were conducted in Middle and Kalsin 

 Bays for two weeks in August from 1991 to 1996. Ju- 

 venile flatfish were collected by using 3.05 and 3.66 m 

 plumb-staff beam trawls (Gunderson and Ellis, 1986). 

 Trawl nets were made of 7-mm square net mesh and had 

 a 4-mm codend liner that retained flatfish as small as 11 

 mm. Sampling methods were consistent for all six years 

 (Norcross et al., 1995; Norcross et al. 3 ). Collections at 

 each sample site included a tow of 10 minutes or less, a 

 vertical CTD (conductivity, temperature and depth) cast, 

 and a sediment grab (0.06-m 3 Ponar grab). The sampling 

 area of each tow was determined by the width of the 

 beam trawl, which was 0.74 of the beam length (Gunder- 

 son and Ellis, 1986), and distance towed was based on 

 global positioning system (GPS) coordinates. Fish were 

 identified to the lowest possible taxon and measured 

 to the nearest millimeter total length. At the time of 

 collections, all rock sole were identified as Pleuronectes 

 bilineatus. Following Orr and Matarese's (2000) revision 

 of the genus, we refer to these fishes as Lepidopsetta 

 spp. in this article because both species, L. bilineata and 

 L. polyxystra, were identified in the study area during 

 1996 sampling. Fish ages were determined by length- 

 frequency analysis. Fish catch-per-unit-of-effort (CPUE) 

 values were standardized to a 1000-m 2 tow area. 



Sampling designs varied from year to year (Norcross 

 et al. 3 ). Extensive exploratory sampling was conducted 



from 1991 through 1994 to describe juvenile flatfish 

 distributions in relation to habitat characteristics (Nor- 

 cross et al., 1995; 1997). The goal in these years was to 

 sample over the widest range of areas and habitat char- 

 acteristics possible within the depth, sediment, weather, 

 and logistical constraints. In 1995 and 1996, sampling 

 was stratified by depth and percent sand in sediment. 

 The sample allocation and the number of strata differed 

 in 1995 and 1996 (Norcross et al. 3 ). Because of logisti- 

 cal constraints, samples were not randomly allocated 

 within each stratum. Within these sampling designs, 

 nine fixed sites were chosen, each with different depth 

 and sediment combinations and with high abundances 

 of one of the four species. Each of the nine fixed sites 

 was sampled at least once in each of the six years. For 

 this study, survey data in each year were treated as 

 unstratified samples that were not collected under a 

 probability sampling design. 



Analysis 



Poststratification Habitat preferences of juvenile fiat- 

 fishes, as defined by depth and sediment variables, have 

 been identified as affecting the distribution and abun- 

 dance of juvenile flatfish around Kodiak Island (Norcross 

 et al., 1995; 1997; 1999; Mueter and Norcross, 1999) and 

 elsewhere (Pearcy, 1978; Tanda, 1990; Burke et al., 1991; 

 Rogers, 1992; Walsh, 1992). Four areas were defined for 

 use in estimating total and relative abundance: habitat, 

 nonhabitat, high fish-density (HFD) and low fish-density 

 (LFD) areas. Percent sand was used as a continuous vari- 

 able of sediment type. Suitable habitat (habitat area) was 

 defined for each species as ranges of depth and percent 

 sand in which the species was caught during one or more 



