364 



Fishery Bulletin 94(2). 1996 



1 70 E 



63 N • 



175 E 



62" N 

 6 I N 

 60''N I 

 59 N - 



57' N 



56"N 



55 'N -I 



54 N 



S3 N I 



52"N 



51 N 



50' N - 

 170 E 



apt-.. 



175 E 



Aleutian Islands 



50"N 



1 80 'W 



175"W 



1 70 W 



55"W 



Figure 6 



Map of Kamchatka flounder, Atheresth.es evermanni, CPUE (kg/ha) over the eastern Bering Sea shelf and 

 slope, in waters off the Aleutian Islands, and in Gulf of Alaska areas. The 50-, 100-, and 200-m bathymet 

 ric contours are not included in the Aleutian Islands and Gulf of Alaska areas owing to complicated 

 bottom topography. 



curring in the Gulf of Alaska was confirmed by mer- 

 istic data recorded from three specimens. These rare 

 occurrences of Kamchatka flounder in the Gulf of 

 Alaska (length range 56-65 cm) were in depths (549- 

 686 m) outside the depth range covered during the 

 Gulf of Alaska bottom trawl survey. 



The mean length of both Atheresthes flounders in- 

 creased with depth, and asymptotic, curvilinear mod- 

 els were fitted to the data 



arrowtooth flounder length = 54.8 - 53.8e' 0im>ill ''i" h , 



(df=131, F=3618.8, P<0.001, R 2 =0.80); 



Kamchatka flounder length = 58.8 - 45.9e- ,MI " r,T ' / ''"\ 



(df=64, F=2123.3, P<0.001, i? 2 =0.75). 



The models show that for much of the size range (-30 

 cm to -50 cm) for both species, Kamchatka flounder 

 of the same length as arrowtooth flounder occur at a 

 greater depth (superimposed on Fig. 1). Kamchatka 



flounder attain a greater length at depth than do 

 arrowtooth flounder in depths greater than 400 m. 



The relationship between length and water tempera- 

 ture was more complex and could be adequately de- 

 scribed only in combination with geographic and depth 

 relationships. The combined results from the eastern 

 Bering Sea and Aleutian Island regions are presented 

 in Table 1. Acomparison of the depth and temperature 

 differences between size groups and between species 

 by statistical analyses was difficult because of lack of 

 independence of the samples (both species were often 

 taken together). Although the differences could not be 

 tested, different size groups appeared to be associated 

 with different depth zones and temperatures. 



Catches of small arrowtooth flounder (<30 cm FL) 

 were associated with shallow areas near the Pribilof 

 Islands, the Alaska Peninsula, and the region north 

 of the eastern Aleutian Islands. Medium-size arrow- 

 tooth flounder ( from <30 to <40 cm FL) were grouped 

 mostly between the 100 m and 200 m isobaths on 

 the eastern Bering LSea shelf and around the central 

 Aleutian Islands. The largest arrowtooth flounder 



