Robards et al : Variation in fish communities of lower Cook Inlet, Alaska 



975 



ence of oceanic water within the bay. Pollock also 

 frequent Amchitka Island nearshore environments, 

 which are similarly bathed by mixed, oceanic waters 

 (Isakson et al., 1971). 



Unequivocal declines in seabird populations (pre- 

 dominantly murres and black-legged kittiwakes) at 

 Chisik Island (Slater et al., 1994) may be related to 

 declines of locally abundant forage fish, particularly 

 sand lance. It is possible that historically larger num- 

 bers of capelin (Piatt and Anderson, 1996) or her- 

 ring (or both) (Rounsefell, 1930; Reid, 1971) may have 

 inhabited this region when stocks of pelagic seabirds 

 were higher prior to the mid-1970s. Colder than av- 

 erage temperatures prior to the late 1970s would 

 have favored both of these fish species (Ware, 1995; 

 Frank etal. 1996). 



Refuge), Minerals Management Service, University 

 of Alaska, Fairbanks (Institute of Marine Science), 

 and the Alaska Department of Fish and Game. All 

 fish were collected under Alaska Department of Fish 

 and Game collection permits. Special thanks are 

 given to J. Blackburn (Alaska Department of Fish 

 and Game) for providing us with raw data from the 

 1976 Cook Inlet survey, to Stephanie Zuniga for pro- 

 viding beach seine assistance at the Barren Islands, 

 and Nancy Tileston for invaluable library assistance. 

 We also thank D. Black, P. Desjardins, J. Figurski, A. 

 Harding, B. Keitt, K. Mangel, M. Schultz, T. Van Pelt, 

 and S. Zador for their dedicated help with fieldwork 

 and logistics. The manuscript benefited from careful 

 reviews by Paul Anderson and one anonymous reviewer. 



Limitations of the study 



Sampling nearshore habitats with beach seines was 

 limited to sandy and cobble substrates. Strong cui'- 

 rents or inshore swells over 0.5 m also prevented ef- 

 fective retrieval of nets. Therefore, fish inhabiting 

 muddy or rocky substrates, mussel (Mytilus ediiUs) 

 and kelp beds, or the surf zone are under-represented 

 in our study. The surf zone is preferentially used by 

 some species because of low numbers of predators 

 and food-rich waters (Bennett, 1989). 



Burrowing fish, such as sand lance, may also be 

 under-represented in the beach seine data because 

 of their ability to escape under the net (Dick and 

 Warner, 1982; Gordon and Leavings, 1984; Allen et 

 al., 1992; Robards, personal obs). However, sand 

 lance were the most abundant fish caught in 

 Kachemak Bay and the Barren Islands, indicating 

 that beach seines were clearly effective for sampling 

 this species. 



'Juvenile cod migrate from deep water habitats 

 during the day to shallower, nearshore waters at 

 night (Methven and Bajdik, 1994; Gibson et al., 

 1996). Therefore, cod and other gadids may be un- 

 der-represented in our catches, which were made only 

 during daylight hours. However, diel variability in 

 gadid catches has been shown to be lower than vari- 

 ability associated with tide cycles (Gibson et al.,1996). 



Acknowledgments 



Major financial and logistic support for the Cook In- 

 let Seabird Forage Fish Study (CISeaFFS) was pro- 

 vided by the Exxon Valdez Oil Spill (EVOS) Trustee 

 Council (APEX project 97 163m), U.S. Geological Sur- 

 vey (Alaska Biological Science Center), U.S. Fish and 

 Wildlife Service (Alaska Maritime National Wildlife 



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