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Fishery Bulletin 105(2) 



Table 4 



Estimates of r^ for the fit of the model (Eq. 9) without length dependency, and the values of /i, ^^ (Eq. 2), and the standard devia- 

 tion (SD) of Kf, for each of the four species of fiatfish. 



Species 



SD(*. 



Arrowtooth flounder lAtheresthes stomias) 

 Flathead sole (Hippoglossoides elassodon) 

 Rex sole (Glyptocephalus zachirus) 

 Dover sole iMicrostomus pacificus) 



respectively (Fig. 5), indicating that slightly more than 

 40% of the largest individuals that passed between the 

 doors of the trawl were ultimately caught. In contrast, 

 the efficiency estimates for Dover sole were considerably 

 lower over the sampled size range and monotonically 

 decreased with increasing fish length. 



Discussion 



Net efficiency 



For three of the four fiatfish species (i.e., arrowtooth 

 flounder, flathead sole, rex sole), net efficiency (^„) 



increased monotonically with fish size. For Dover sole, 

 however, net efficiency declined over the sampled size 

 range and was considerably lower than that for the other 

 species in the larger commercial sizes. This unusual 

 pattern is likely the result of two factors. First, small 

 individuals, which are likely better at escaping under 

 the footrope, were not sampled; consequently, the left- 

 hand, ascending, portion of the selection curve is not 

 defined. Second, the decline in capture probability with 

 increasing size indicates that this species is behaviorally 

 more adept at escaping under the footrope, probably by 

 swimming ahead of the footrope, then dropping to the 

 bottom, and allowing the footrope to pass over. Although 

 distinct species-specific escape responses to a footrope 



