UNIT 15 

 PACIFIC COAST GROUNDFISH FISHERY 



Ecosystem Considerations 



Accurate, long-term predictions ot potential 

 yield will reqtiire a substantial increase in our 

 knowledge about competitive and predatory in- 

 teractions in the biological system that includes 

 Pacific Coast groundfish, and about climate ef- 

 fects on this community. The target exploitation 

 rate tor most groundfish species is designed to 

 achieve a large fraction of maximum potential 

 yield, while reducing the abundance ot spawners 

 by about two-thirds, in expectation that this will 

 not reduce the mean recruitment level. However, 

 we have been monitoring some ot these stocks for 

 not much more than the span ot just one of their 

 generations. Only decades ot monitoring the 

 stocks performance will ascertain the long-term 

 feasibility of these targets, and the degree ot natu- 

 ral fluctuation that will occur while maintaining 

 these targets. Unfortunately, there is little histori- 

 cal data, and the current level of stock assessment 

 data is not adequate to precisely track changes in 

 abundance tor more than a tew species. In addi- 

 tion, only a low level ot ettort is directed towards 

 food habits studies that may help predict how the 

 interactions among species may change as the 

 abundance of several major species is reduced be- 

 low untlshed levels. 



Models of long-term potential yield depend 

 on assumptions ot constant average environmen- 

 tal conditions or an abilit)- to predict changing 

 conditions. There is evidence ot a decline in zoop- 

 lankton abundance within the Calitornia Coop- 

 erative Oceanic Fisheries Investigations' 40-year 

 time series (McGowan et al., 1998), as well as of 

 an ocean warming during the late 1970s (Francis 

 and Hare, 1997). Dover sole in southern areas and 

 bocaccio rockfish and lingcod exhibit declines in 

 mean recruitment during this same period. Better 

 understanding ot potential linkages between tish 

 recruitment and li)ni;-term changes in the ocean 



climate are key to improved 'i- to 10-year tore- 

 casts ot fishery potential yield. 



LITERATURE CITED 



PFMC (Pacific Fishery Management Council). l')')7. 

 Status of the Pacific Coast groundfish fishery through 



1997 and recommended biological catches for 1998: 

 stock assessment and fishery evaluation. Pacific Fish- 

 ery Management Council, 21230 SW Fifth Avenue, 

 Suite 224, Portland, OR 9720 1 . 



PFMC (Pacific Fishery Management Council). 1998. 

 Status of the Pacific Coast groundfish fishery through 



1998 and recommended biological catches for 1999: 

 stock assessment and fishery c\aluation. Pacific Fish- 

 ery Management Council, 212.^0 SW Fifth Avenue, 

 Suite 224, Portland, OR 97201 . 



Francis, R. C, and S. R. Hare. 1994. Decadal-scale 

 regime shifts in the large marine ecosystems ot the 

 Northeast Pacific: a case for historical science. Fish- 

 eries Oceanography 3:279-29 1 . 



McCowan, ]. A., D. R. Cayan, and L. M. Dorman. 

 1998. Climate-ocean variability and ecosystem re- 

 sponse in the Northeast Pacific. Science 281:210-217. 



Mixed catch of rockfish, 

 sablefish, and Dover sole off 

 Oregon coast. 



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