Pacific Salmon: Ecology and Management of Western Alaska’s Populations

<em>Abstract.</em>—Limits to the capacity of the North Pacific Ocean to support salmon are suggested based on widespread observations of decreasing size and increasing age of salmon at maturation during time periods where the abundance of salmon has increased throughout the North Pacific rim. The increase in abundance of salmon is partially due to successful establishment of large-scale hatchery runs of chum salmon <em>Oncorhynchus keta </em>and pink salmon <em>O. gorbuscha</em>. The largest hatchery runs are chum salmon, and because of their long life span relative to the more abundant pink salmon, the increase in hatchery terminal run biomass under-represents the actual increase in salmon biomass. To put the increase in hatchery runs in perspective, the historical (since 1925) terminal runs and biomass of hatchery and wild pink, chum, and sockeye salmon <em>O. nerka </em>in the North Pacific Ocean were reconstructed. Various data sets of smolt releases from hatcheries, wild salmon estimates of smolt out-migrants, and subsequent adult returns by age and size were assembled. Age-structured models were fit to these data sets to estimate brood-year specific rates of natural mortality, growth, and maturation. The rates were then used to reconstruct total biomass of the “smolt data” stocks. The estimated ratio of terminal runs to total biomass estimated for the “smolt data” stocks were used to expand the historical time series of terminal run biomass on a species and area basis. The present total biomass (~4 million mt) of sockeye, chum, and pink salmon in the North Pacific Ocean is at historically high levels and is ~3.4 times the low levels observed in the early1970s. At least 38% of the recent ten-year average North Pacific salmon biomass is attributed to hatchery stocks of chum and pink salmon. Recent year terminal run biomass has been greater than the peak levels observed during the mid 1930s.

2010 ◽  
Vol 2 (1) ◽  
pp. 306-328 ◽  
Author(s):  
Gregory T. Ruggerone ◽  
Randall M. Peterman ◽  
Brigitte Dorner ◽  
Katherine W. Myers

2011 ◽  
Vol 68 (6) ◽  
pp. 1122-1130 ◽  
Author(s):  
James R. Irvine ◽  
Masa-aki Fukuwaka

Abstract Irvine, J. R., and Fukuwaka, M. 2011. Pacific salmon abundance trends and climate change. – ICES Journal of Marine Science, 68: 1122–1130. Understanding reasons for historical patterns in salmon abundance could help anticipate future climate-related changes. Recent salmon abundance in the northern North Pacific Ocean, as indexed by commercial catches, has been among the highest on record, with no indication of decline; the 2009 catch was the highest to date. Although the North Pacific Ocean continues to produce large quantities of Pacific salmon, temporal abundance patterns vary among species and areas. Currently, pink and chum salmon are very abundant overall and Chinook and coho salmon are less abundant than they were previously, whereas sockeye salmon abundance varies among areas. Analyses confirm climate-related shifts in abundance, associated with reported ecosystem regime shifts in approximately 1947, 1977, and 1989. We found little evidence to support a major shift after 1989. From 1990, generally favourable climate-related marine conditions in the western North Pacific Ocean, as well as expanding hatchery operations and improving hatchery technologies, are increasing abundances of chum and pink salmon. In the eastern North Pacific Ocean, climate-related changes are apparently playing a role in increasing chum and pink salmon abundances and declining numbers of coho and Chinook salmon.


1994 ◽  
Vol 51 (6) ◽  
pp. 1430-1442 ◽  
Author(s):  
Eric B. Taylor ◽  
Terry D. Beacham ◽  
Masahide Kaeriyama

We examined geographic variability in minisatellite DNA in chum salmon (Oncorhynchus keta) from 42 populations from the North Pacific Ocean to (1) determine the extent of regional population structure at minisatellite loci and (2) assess the ability of minisatellite variability to determine the geographic origin in individual chum salmon. Restriction fragments from 1.6 to 13.6 kilobase pairs in molecular weight were resolved with a minisatellite probe. The fragments were inherited from parent to offspring and appeared to represent segregation at two linked loci. Minisateliite DNA variability was negligible between annual samples from the same rivers, and chum salmon fell into three regional population groupings: (i) Japanese, (ii) Russian/Yukon River, and (iii) southeastern Alaska/British Columbia salmon. These regional groupings probably reflect historical patterns of postglacial dispersal of chum salmon from three distinct refugia in the North Pacific. We used restriction fragment counts as input to linear discriminant and neural network classification of independent test samples of salmon. Accuracies of 90–95, 81–86, and 72–80% were achieved when classifying fish as of either Japan/Russia/Yukon River versus southeastern Alaska/British Columbia origin, Japan versus Russia/Yukon River origin, or Russia versus Yukon River origin, respectively.


1993 ◽  
Vol 50 (2) ◽  
pp. 290-295 ◽  
Author(s):  
Yukimasa Ishida ◽  
Soto-o Ito ◽  
Masahide Kaeriyama ◽  
Skip McKinnell ◽  
Kazuya Nagasawa

Changes in age composition and size of adult chum salmon (Oncorhynchus keta) from rivers in Japan, Russia, and Canada were examined based on body weight and scale measurement data collected from 1953 to 1988. A significant increase in mean age was found in Japanese and Russian stocks after 1970 when the number of Japanese chum salmon began to increase exponentially, but not in the Canadian stock. Significant decreases in mean body weight, mean scale radius, and mean width of the third-year zones of age 4 chum salmon also occurred in Japanese and Russian stocks after 1970. Based on the Japanese salmon research vessel data from 1972 to 1988, significant negative relationships between catch-per-unit-effort and mean body weight of chum salmon were observed in summer in the central North Pacific Ocean where the distribution of Japanese and Russian stocks overlaps. These results suggest that density dependence is one of the possible causes for the recent changes in age and size of chum salmon in the North Pacific Ocean.


2011 ◽  
Vol 94 (4) ◽  
pp. 663-668 ◽  
Author(s):  
W. Tyler McCraney ◽  
Edward V. Farley ◽  
Christine M. Kondzela ◽  
Svetlana V. Naydenko ◽  
Alexander N. Starovoytov ◽  
...  

2018 ◽  
Vol 115 (22) ◽  
pp. E5038-E5045 ◽  
Author(s):  
Alan M. Springer ◽  
Gus B. van Vliet ◽  
Natalie Bool ◽  
Mike Crowley ◽  
Peter Fullagar ◽  
...  

Pink salmon (Oncorhynchus gorbuscha) in the North Pacific Ocean have flourished since the 1970s, with growth in wild populations augmented by rising hatchery production. As their abundance has grown, so too has evidence that they are having important effects on other species and on ocean ecosystems. In alternating years of high abundance, they can initiate pelagic trophic cascades in the northern North Pacific Ocean and Bering Sea and depress the availability of common prey resources of other species of salmon, resident seabirds, and other pelagic species. We now propose that the geographic scale of ecosystem disservices of pink salmon is far greater due to a 15,000-kilometer transhemispheric teleconnection in a Pacific Ocean macrosystem maintained by short-tailed shearwaters (Ardenna tenuirostris), seabirds that migrate annually between their nesting grounds in the South Pacific Ocean and wintering grounds in the North Pacific Ocean. Over this century, the frequency and magnitude of mass mortalities of shearwaters as they arrive in Australia, and their abundance and productivity, have been related to the abundance of pink salmon. This has influenced human social, economic, and cultural traditions there, and has the potential to alter the role shearwaters play in insular terrestrial ecology. We can view the unique biennial pulses of pink salmon as a large, replicated, natural experiment that offers basin-scale opportunities to better learn how these ecosystems function. By exploring trophic interaction chains driven by pink salmon, we may achieve a deeper conservation conscientiousness for these northern open oceans.


Sign in / Sign up

Export Citation Format

Share Document