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Fishery Bulletin 103(4) 



and recreational fisheries, and gear cost for each fishery 

 varied greatly; therefore, an average estimate for each 

 gear type was used to estimate gear loss for commer- 

 cial and recreational fisheries. Total revenue losses as 

 a result of fish taken by sea lions in the commercial 

 fishery were equivalent to between 14.2% and 84.4% of 

 the total salmon fishery revenues. 



Discussion 



Conflicts between pinnipeds and fisheries are well docu- 

 mented in California (Briggs and Davis, 1972; Fiscus, 

 1979; Ainley et al., 1982; Miller et al. 6 ; Hanan et al., 

 1989; Beeson and Hanan 1 ; NMFS 2 ). California sea lions 

 have been the primary pinniped species involved in 

 taking fish in ocean commercial and recreational salmon 

 fisheries (Miller et al. 6 ; Hanan et al., 1989; Beeson and 

 Hanan 1 ). In comparing present results and past studies 

 it is imperative to distinguish between the percentage 

 of salmon taken by pinnipeds relative to the number of 

 legal size fish landed (i.e. legal catch) and number of pin- 

 niped takes relative to total number offish hooked (i.e., 

 total catch). The former value inflates percentages by 

 not including undersize fish caught, whereas the latter 



includes all fish hooked in the calculation and assumes 

 all fish, regardless of size, have an equal probability of 

 being taken by sea lions. 



Dockside surveys were representative of the mag- 

 nitude of interactions between sea lions and salmon 

 fisheries because there were no significant differences in 

 mean percentages of takes by sea lions between onboard 

 and dockside surveys. Onboard surveys alone would not 

 provide sufficient samples to adequately assess levels 

 of interactions between sea lions and salmon fisheries; 

 conversely, the validity of dockside surveys alone would 

 be questionable because of biases associated with dock- 

 side surveys. Biases included fishermen not providing 

 truthful information, fishermen avoiding the survey, 

 fishermen not answering all questions, and not all fish- 

 ermen returning to the docks. Combining onboard and 

 dockside surveys enabled us to verify dockside findings, 

 obtain sufficient levels of sampling for comparisons, 

 and directly observe and understand the nature of the 

 interactions. 



The percentage of hooked salmon taken by sea lions 

 in the commercial salmon fishery in relation to the legal 

 catch has increased by at least 8% since the 1970s and 

 1980s. Briggs and Davis (1972) reported that California 

 sea lions took 4.1% of all salmon hooked during the 



