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METHODS AND MATERIALS 



Sample Collection and 

 Stomach Content Analysis 



Stomachs from 1,333 Greenland halibut were 

 collected from May 1983 to November 1985 in the 

 eastern Bering Sea area (Fig. 1) from NMFS re- 

 search vessels and foreign commercial fishing 

 vessels (through the U.S. Foreign Fisheries Ob- 

 server Program). A bottom trawl was the only sam- 

 pHng gear used, and trawl samples were taken 

 throughout the day and night. Due to the low abun- 

 dance of Greenland halibut in the shelf area (<200 

 m), stomachs were taken from virtually all Green- 

 land halibut encountered in trawl catches. Random 

 size-stratified samples were obtained from the 

 catches in the slope area. Captured fish were 



checked in ihv i'lvld for signs of regurgitation and 

 were discarded when there was evidence of food 

 items in the mouth or gill plates or of flaccid 

 stomachs. Stomachs from the sampled fish were ex- 

 cised and put into cloth bags with a specimen label 

 containing fork length, sex, and station information, 

 and were preserved in 4% formaldehyde solution. 

 Individual fish weights were not recorded at sea, but 

 were estimated by using the weight-length equation. 



W{g) = 0.0060717 x L(cm) 



i08K(;4 



(1) 



estimated from the Greenland halibut data base of 

 the Resource Assessment and Conservation Engi- 

 neering (RACE3) Division of the NWAFC. 



•^Northwest and Alaska Fisheries Center, National Marine Fish- 

 eries Service, 7600 Sand Point Way N.E., BIN C1.5700, Building 

 4, Seattle, WA 98115. 



63 OON 



■- 61 OON 



59 OON 



■- 57 OON 



-■- 55 OON 



■■- 53 OON 



51 OON 



1 79 OOE 



176 OOW 



171 OOW 



166 OOW 



161 OOW 



156 OOW 



Figure 1. -Sampling locations for Greenland halibut in the eastern Bering Sea by four different depth strata, <200 m ( + ), 200-.399 



m (O), 400-599 m (■), and >600 m (A). 



676 



