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Fishery Bulletin 93(4). 1995 



Ichthyoplankton collections were made at 92 stations 

 off Kodiak Island and the Alaska Peninsula (151- 

 159°W) from 17 to 25 May 1991 by using a 60-cm bongo 

 with either 333- or 505-um mesh. Processing of these 

 samples and abundance estimates were done as de- 

 scribed for the Methot trawl collections. More complete 

 sampling details are provided by Dewitt and Clark. 1 



Results 



Gear comparisons 



The two gear types did not show significant differ- 

 ences in overall mean standardized catches of age-0 

 T. chalcogramma for the four paired gear-compari- 

 son hauls, but when the densities were partitioned 

 by size offish, the Methot trawl caught significantly 

 more fish in the smallest size groups, although there 

 were no density differences between the two gears for 

 the size groups >35 mm (Fig. 2). Although it was not 

 possible to examine diel differences in overall age-0 

 densities for both gear types from only four stations 

 taken in different locations, it appears that the 

 catchability of small T. chalcogramma by the anchovy 

 trawl is relatively poor during the daytime. In all 

 four comparisons, the Methot trawl caught smaller 

 individuals and a broader overall range of age-0 sizes 

 than did the anchovy trawl, but the distributions of 

 lengths were significantly different in only two of the 

 four tows (Fig. 3). The overall average (+SD) length 

 of individuals caught by the Methot net was 34.5 

 (±7.0) mm, whereas the average length offish caught 

 by the anchovy trawl was 36.3 (±4.5) mm. 



Taxonomic composition and abundance 



Altogether, 53 larval and 4 juvenile taxa were iden- 

 tified in the Methot trawl survey (Tables 1 and 2). 

 Several taxa, notably Sebastes spp. and Cyclop- 

 teridae, were probably represented by several as yet 

 unidentifiable species; therefore, the overall taxo- 

 nomic diversity was probably underestimated. The 

 family Cottidae exhibited the greatest diversity, with 

 at least 15 taxa represented (Table 1). 



Hippoglossoides elassodon, T. chalcogramma, and, 

 to a lesser extent, Atheresthes stomias, G. macro- 

 cephalus, and Icelinus spp., were the dominant taxa 

 collected on the basis of mean density (Table 1). 

 Hippoglossoides elassodon larvae were the most 

 abundant overall and occurred at all but one station. 

 Most of the fish caught were late-stage larvae, but T. 

 chalcogramma and G. macrocephalus were also rep- 

 resented by a large number of juveniles (Table 2). 

 On the basis of total abundance in the study area, 



H. elassodon, T. chalcogramma, and A. stomias are 

 clearly the most abundant taxa; there is less distinc- 

 tion among the rest of the dominant taxa (Fig. 4). 

 The abundance of H. elassodon (3.24 x 10 10 fish) was 

 almost three times that of the next most abundant 

 species T. chalcogramma (larvae and juveniles com- 

 bined: 1.12 x 10 10 fish) and represented 53.6% of the 

 estimated total abundance of ichthyoplankton in the 

 survey area (6.04 x 10 10 fish). 



Spatial and length-distribution patterns 



The geographic and length distributions of the six 

 most abundant larvae and T. chalcogramma and G. 

 macrocephalus juveniles are shown in Figures 5-8. 

 The distribution of T. chalcogramma larvae and 

 that of juveniles were very similar, with centers of 

 abundance near the Semidi and Shumagin Islands 

 (Fig. 5). Gadus macrocephalus juveniles tended to 

 be distributed slightly more offshore and farther west 

 (downcurrent) than were larvae (Fig. 6). Hippogloss- 

 oides elassodon larvae were found in greatest num- 

 bers near the Alaska Peninsula and Shumagin Is- 

 lands, whereas A. stomias larvae were collected over 

 a broad size range and displayed no distinct patterns 

 of distribution (Fig. 7). In contrast, Icelinus spp. lar- 

 vae showed a narrow size distribution and were found 

 in high concentrations northeast of Sanak Island 



16 



12 



E 

 o 



° a 



o 8 



^|= Anchovy 

 I 1 = Methot 



XL 



Standard Length (mm) 



Figure 2 



Comparison of the standardized catches for the Methot 

 and anchovy trawl by length category in the gear com- 

 parison tows. 



