Weise and Harvey Impact of Zalophus californianus on salmon fisheries 



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Table 1 



Commercial and recreational salmon fishery seasons in the Monterey Bay region from 1997 to 1999. 



Commercial 



Recreational 



1997 

 1998 

 1999 



1-31 May, 23 June-18 July, 1-30 September 

 1-31 May, 16 June-30 September 

 1 May - 21 August, 1-30 September 



15 March-19 October 

 14 March-7 September 

 14 March-6 September 



onboard sampling in areas where interaction was more 

 prevalent (Miller et al. 6 ). During this study, captains 

 were requested during onboard observations to conduct 

 normal fishing operations and not to intentionally seek 

 out areas with greater or lesser rates of interaction 

 between sea lions and fishery operations. 



Sampling of commercial and recreational salmon 

 fisheries was stratified by month and approximately 

 equal numbers of onboard and dockside surveys were 

 conducted monthly. Sampling days and ports were se- 

 lected randomly for onboard and dockside surveys of 

 commercial fishing operations, but onboard surveys 

 were limited by crew cooperation and space availabil- 

 ity. Each onboard survey in the commercial fishery 

 took a full fishing day onboard one boat, and dockside 

 interviews were conducted during four-hour periods in 

 the middle to late afternoon during the peak time that 

 vessels returned to port. For CPFVs, which operate 

 virtually every day but have a greater number of boats 

 and passengers on weekends, two-thirds of onboard and 

 dockside sampling dates were selected randomly from 

 possible weekend dates and one-third from all possible 

 weekdays. Onboard surveys of CPFV took a full fishing 

 day aboard one vessel, and dockside surveys took two 

 to three hour periods in early afternoon during peak 

 return times for CPFVs at a randomly selected port. 

 The goal of CPFV dockside surveys was to sample (for 

 the sampling day) all CPFVs targeting salmon and that 

 had returned to port. In the skiff fishery, greater num- 

 bers of fishing trips occurred on weekends; therefore 

 approximately three-quarters of sampling days occurred 

 on weekends, and one-quarter occurred on weekdays. 

 Onboard surveys in 1997 aboard one skiff took a full 

 fishing day, and dockside surveys from 1997 to 1999 

 were conducted during two-hour sampling periods in 

 late morning and early afternoon during the peak re- 

 turn time for private skiffs. 



In 1997, four onboard surveys were conducted in the 

 commercial and CPFV fishery, and five onboard pri- 

 vate skiff surveys were conducted. Whereas in 1998 

 and 1999. in an effort to increase onboard sample size, 

 survey effort was concentrated in the commercial and 



6 Miller, D. J., M. J. Herder, and J. P. Scholl. 1983. Cal- 

 ifornia marine mammal-fishery interaction study, 1979- 

 1981. NMFS Southwest Fish. Cent., Admin. Rep. LJ-83-13C, 

 233 p. Southwest Fisheries Science Center, 8604 La Jolla 

 Shores Drive, La Jolla, CA 92037-1508. 



Figure 1 



Primary fishing ports used by commercial and recre- 

 ational salmon vessels, and pinniped haul-out sites 

 in Monterey Bay, California. 



CPFV fisheries; 22 surveys conducted each year in each 

 fishery. 



Information collected at dockside included port of 

 call, number of fish landed, number of fish taken by 

 pinnipeds at or below the surface, species and number 

 of marine mammals involved in surface take, number of 

 fish released, number of released fish taken by marine 

 mammals, and type and amount of gear loss. Onboard 

 surveys included the same information collected at 

 dockside, as well as standard length of all fish landed. 



Commercial troll and recreational salmon fisheries 

 use different types of fishing gear, which can affect 

 the nature and magnitude of their interactions with 

 pinnipeds. Commercial salmon trolls are designed 

 to catch fast-swimming fishes by using flashy lures 

 that are trolled behind the moving vessel on heavily 



