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Fishery Bulletin 103(1) 



June and July, only in the innermost parts of 

 Kiliuda Bay and Ugak Bay, may indicate an 

 alternative mechanism such as local spawn- 

 ing and geographic differences in retention. 

 Regardless, the relationship between fish 

 size and hatching date indicates that large 

 individuals were spawned early; thus, early 

 spawned individuals might experience higher 

 overwinter survival, which often increases 

 with fish size (Sogard, 1997). 



We chose to track echo sign in our study 

 to reduce the sampling effort expended in 

 areas devoid of age-0 pollock. This meth- 

 od maximized our chance of collecting the 

 samples needed to study differences among 

 age-0 pollock given the limited vessel time. 

 Unfortunately, this method also introduced 

 a bias, thereby reducing the utility of den- 

 sity estimates to indicate habitat suitability 

 (Brown et al., 2000; Stoner et al., 2001) and 

 to extrapolate from samples to at-sea popu- 

 lations. Our focus, however, was on other 

 measures that might eventually provide a 



