716 



Fishery Bulletin 98(4) 



Diet 



A total of 32 different prey items were identified from 

 93 stomachs of fish collected in 1997 (Table 1). Fre- 

 quency of occurrence analysis indicated that gammarid 

 amphipods and polychaete worms were the most common 

 prey items; crangonid shrimp and bivalves were encoun- 

 tered less frequently. Similarily prey total count indicated 

 that gammarid amphipods were the most numerous prey 

 items encountered but no other single item was found 

 in large numbers. Crangonid shrimp predominated by 

 total weight; Pacific sandlancc (Ammodytes hexapterufi), 

 gammarid amphipods, and polycheates were secondarily 

 important and were of approximately equal weight. 



The relation between fish size and diet composition 

 showed a shift from predominantly small benthic am{)hi- 

 pods to increasingly larger prey items, such as crangonid 

 shrimp and fish with increased fish TL (Fig. 9). Total 



diet weight proportion showed similar trends; crangonid 

 shrimp and fish became more important and gammarid 

 amphipods decreased in diet weight proportion as fish 

 increased in TL (Fig. 10). 



Discussion 

 Distribution 



Gymnocanthus pistilliger is abundant in the spring to 

 early summer (May and June) near the mouth of Kuskok- 

 wim and Togiak Bays and throughout the shallow areas 

 of Bristol Bay. This area is characterized by relatively 

 shallow water (<50 m) and has a sandy to muddy bottom 

 (McDonald et. al. 1981). The Togiak River and Kuskok- 

 wim River discharge large amounts of fresh water into the 

 shallow estuarine environment creating fluctuating tern- 



