Imminent climate and circulation shift in northeast Pacific Ocean could have major impact on marine resources

Abstract

A climate shift is imminent in the northeast Pacific Ocean, research suggests, and may have a major impact on marine resources, particularly Pacific salmon. Scientists anticipate that the shift, driven by large‐scale changes in the Earth's atmospheric wave pattern, will become evident in the next few years. The most recent shift, characterized by a switch from cold and wet conditions to warm and dry conditions in the Pacific northwest of the United States, occurred in 1977 [e.g., Trenberth and Hurell, 1994]. The expected climate shift is suggested by studies of oscillations in ocean surface water drift and in treering records. Drift trajectories, derived from a new measure of decadal variability, showed well‐defined oscillations in the 20th century, but researchers were concerned that this decadal nature might not be as evident over a considerably longer time. Thus because of the possible rarity of the 30‐year interval since the last climate shift, treering width data was scrutinized for the western juniper for the period from 1500 to 1900 A.D.

Pacific Basin climate variability and patterns of Northeast Pacific marine fish production

“…In the northern regions, Niño North conditions depend on the influence of atmospheric forcing on the position and intensity of the Aleutian low. Surface flow trajectories simulated using the Ocean Surface CURent Simulations (OSCURS) model reveal that Niño North conditions coincide with years of strong northward advection directed into the head of the Gulf of Alaska (Ingraham, Ebbesmeyer, & Hinrichsen, 1998). These simulations are consistent with Strub's review (pers.com.)…”

Decadal‐scale patterns in the relative year class success of sablefish (Anoplopoma fimbria)

“…This is particularly useful when climate–ocean indices suggest that a regime shift has recently occurred or is now occurring. It is possible that a regime shift has recently occurred around 1996/97 ( Beamish et al ., 1998 ; Ingraham et al ., 1998 ) and is detectable as an intense Aleutian Low in the winter of 1997/98. If this is correct, then based on the patterns we report here, it would be plausible that sablefish production may switch to a period with above‐average year class success.…”

Shifting control of recruitment of walleye pollock Theragra chalcogramma after a major climatic and ecosystem change

“…Analysis of tree nngs and other histoncal data indicate that climate regime-shifts in the North Pacific Ocean have occurred on the average every 15 yr since the time of Columbus (Ingraham et al 1998) or longer. Not all changes have been as strong as the late-1970s shift, but comparable events have occurred many times over the past several centunes (Wiles et al 1998).…”