Aquatic Ecosystems: Current Research
Climate Impacts on the PNW Coastal Marine Ecosystem, Fisheries, and Fisheries Assessment and Management
Pacific sardine (Sardinop sagax) and Pacific hake (Merluccius
productus) are two coastal pelagic species dominating the California
Current Ecosystem and are the bases of important fisheries along
the U.S. west coast. Both species reproduce off the coasts of California
and northern Mexico and exhibit large-scale migrations to feed in regions
off Oregon, Washington and British Columbia. Their population dynamics
however are very different.
Pacific hake abundance increases rapidly due to single large year classes (Figure 1), showing evidence of an interannual signal of variability. The sardine population, on the other hand, slowly increases in response to a series of strong year classes (Figure 2), showing evidence of an interdecadal signal of variability.
click image to enlarge
Figure 1 Time series of Pacific hake biomass and recruitment (data from Hessler, National Marine Fisheries Service-North West Center).
click image to enlarge
Figure 2 Time series of Pacific sardine biomass and recruitment (data from Conser et al. 2002).
Marine organisms have shown a broad range of responses to spatial and temporal changes in the environment. Hollowed et al. (2001) show production patterns of Pacific salmon and flatfish to be consistent with the Pacific Decadal Oscillation (PDO), while those of North Pacific gadids (see sidebar) were shown to be consistent with the El Niño/Southern Oscillation (ENSO).
Holmgren (2001) also suggests different responses of fish species to climate variability. We hypothesize that Pacific hake and sardine respond differently to climate variability. Their response is driven by the impact of climate on their habitats at critical life history stages.
This study focuses on sardine and hake for several reasons: (1) they are an important trophic link in the California Current Ecosystem; (2) their different life histories provide for an instructive comparison; (3) they are an important component to Pacific Northwest fisheries; and (4) the data and information on these species is abundant due to their ecological and commercial importance in the California current and eastern boundary currents worldwide.
- How does climate variability impact the structure and location of sardine and hake habitat in the California Current System?
- How does the relationship between climate and ocean habitat of sardine and hake affect such manifestly different patterns in population dynamics?
- How might an awareness of this relationship in turn affect the way that we assess and manage their fisheries in the California Current Ecosystem?
For publications on the Climate Impacts Group’s (CIG) research on climate and aquatic ecosystems, please see CIG Publications.
Conser, R. J., K. T. Hill, P. R. Crone, N. C. H. Lo and D. Bergen. 2001. Stock assessment of Pacific Sardine with management recommendations for 2002-Executive summary. Submitted to the Pacific Fishery Management Council (Portland, Oregon), October.
Hollowed A. B., S. R. Hare, and W. S. Wooster. 2001. Pacific basin climate variability and patterns of northeast Pacific marine fish production. Progress In Oceanography 49:257-282.
Holmgren, D. 2001. Decadal-centennial variability in marine ecosystems of the Northeast Pacific Ocean: the use of fish scales depositions in sediments. PhD. dissertation, School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA.