Table 2. Criteria for selecting target species in U.S. GLOBEC Northeast Pacific studies. (Modified from a table presented in U.S. GLOBEC Report 11. (U.S. GLOBEC, 1994))

• Likely to be impacted by hypothetical climate change scenarios

• Economically or ecologically important, either as a dominant member of the ecosystem, or through interactions with other species

• Has larval planktonic stage or is holoplanktonic

• Evidence that life history variability is linked to environmental variability

• Widely distributed species, or having life-histories and/or ecological interactions representative of many other species, thus providing opportunities for large-scale spatial comparisons

• Demonstrated evidence of long-term shifts in abundance

• Distribution associated with physical features and/or faunal boundaries

• Analogous species occur in other ecosystems

• Has existing long-term record of abundance (and maybe distribution and growth)

Although juvenile salmon do not have a planktonic larval stage, they are selected as target species because they satisfy all of the other U.S. GLOBEC criteria, and because during the presumed "critical" period of its ocean life history, alongshore (and perhaps offshore) advection may overpower their swimming ability. Moreover, salmon have shown responses in growth or survival to interdecadal or shorter period (e.g., El Niño's impact upon Oregon coho) alterations of the ocean environment. For example, salmon catches from the North Pacific increased sharply in the late 1970's, especially in Alaska (Pearcy 1992; Beamish and Bouillon 1993; Francis and Hare 1994; see Fig. 9). During this recent period of high production, the sizes of maturing salmon in some North American and Asian populations were diminishing (Kaeriyama 1989; Ishida et al. 1993); however, the role of climate variation in this trend is unclear.

Table 4. Suggested other species in the Northeast Pacific that might be monitored, modeled and studied retrospectively during U.S. GLOBEC studies.

To meet the general goal of the U.S. GLOBEC Northeast Pacific program (see p. 18), monitoring, modeling and retrospective data analysis should examine the broadest suite of species and issues relevant to the effects of climate change on North Pacific coastal ecosystems. Table 4 lists additional species whose abundances could be examined during past and future periods, through retrospective analysis and monitoring, respectively.

Where appropriate, non-target fish or benthic species, like hake and mackerel in the CCS and pollock and herring in the CGOA, could be studied with respect to their impact on the target species, focusing on describing their distribution, abundance, and predation rates. Studies on non-target species (Table 4) may be justified when such studies will be valuable for characterizing the nearshore environment (e.g., mesoplankton stages of some of the benthic invertebrates, small pelagic fishes). For example, characterizing the variability in the physical and biological environment using multiple "transects" stretching from Monterey up around the basin to the Shelikof Strait (Kodiak Island) region (see the sections below on Monitoring and Process Studies) is a core component of the Northeast Pacific program. The distributions and settlement patterns of meroplanktonic larvae of adult benthic species (e.g., crabs, urchins, mussels, barnacles, etc.), even though they are not named as target species for full population-dynamics oriented process studies, should be monitored within these transect programs because of the details they will provide on the nearshore conditions, where salmon mortality is hypothesized to occur. Likewise, retrospective studies of small pelagic fish population fluctuations provide information on basin-scale climatic changes that appear to also affect salmon stocks (Fig 3).

Despite the emphasis in the program on juvenile salmon, U.S. GLOBEC hopes that sufficient data are collected on all components of the coastal Northeast Pacific ecosystem so that explicit comparisons can be made to the studies being conducted on Georges Bank in the Northwest Atlantic. This will clearly occur in the holozooplankton where similar species, Calanus finmarchicus in the Atlantic, and Neocalanus and Calanus in the Pacific are target species. Data collected on gadids, especially pollock in the CGOA, during the monitoring and process studies, even if they are not the target species, will be valuable for comparing to the gadids, cod and haddock, of the Atlantic. Such comparisons across the regional U.S. GLOBEC programs will provide a broader understanding of the processes structuring marine systems.

Some species of subarctic and transitional holoplankton (e.g., copepods Eucalanus bungii, Calanus marshallae, Calanus pacificus, Metridia pacifica; euphausiid Euphausia pacifica, Thysanoessa spinifera) are common in both the CCS and CGOA. Euphausia pacifica, for example, has centers of abundance in both the Gulf of Alaska and off central and southern California (Brinton 1962). Genetic studies on these stocks may be valuable in examining relationships between broad-scale circulation patterns and population structures. Other species of subarctic holoplankton (e.g., copepods Neocalanus plumchrus, N. flemingeri, euphausiid Thysanoessa longipes) are more restricted to the northern regions, rarely becoming abundant in the CCS.

Few fishes have natural ranges which encompass both the CCS (Oregonian-San Diegan Provinces) and CGOA (Boreal Province) regions of the eastern North Pacific. Within the salmon, sockeye, pink and chum predominate in the CGOA (Alaska and British Columbia), whereas, coho and chinook are the more important species further south (Washington, Oregon and California). U.S. GLOBEC will focus on pink salmon (Oncorhynchus gorbuscha) in the CGOA and coho (Oncorhynchus kisutch) and chinook (Oncorhynchus tshawytscha) salmon in the CCS. Other fish species will be studied where they compete with the salmon for food or prey upon the target juvenile salmon. Pollock (Theragra chalcogramma) and herring (Clupea pallasi) are important to the trophodynamic pathways in the CGOA ecosystem. Pollock are not found off Washington, Oregon and California. Herring are important in the northern realm of the CCS (off Vancouver Island), but are not as abundant and important ecologically further south (Schwiegert, 1995). The small pelagics of note in the south are the Pacific sardine (Sardinops sagax) and northern anchovy (Engraulis mordax), which off southern California have populations out of phase. Centers of spawning for both are south of Pt. Conception (or in the Columbia River plume for the northern population of Engraulis), but during the recent warm period (esp. post-1990), successful spawning has occurred further north off Oregon, Washington and perhaps, British Columbia. Pacific hake (Merluccius productus) are abundant over the shelf and slope from ca. 25° to 50°N. Adult hake migrate to the northern end of their range during the summer, where they are important consumers, especially of euphausiids and herring (Tanasichuk et al. 1991). In the autumn they migrate ca. 2000 km equatorward to spawn (mostly in January to March) in the waters offshore of the Southern California Bight and Baja California (Bailey et al. 1982). Hollowed and Bailey (1989) show that year-class strength in hake is usually established within 1-3 months of spawning--i.e., during their periods in warm waters offshore of the southern California Bight. Birds and mammals are likely to be important predators on juvenile salmon, especially in the CGOA.