Stomach Contents of Salmon and Steelhead Trout in the Northeastern Pacific Ocean

1966 ◽  
Vol 23 (1) ◽  
pp. 85-100 ◽  
Author(s):  
R. J. LeBrasseur

Stomachs of pink, chum, sockeye, and coho salmon and steelhead trout caught during the summer of 1958 in gillnets fished overnight in the northeastern Pacific Ocean contained mainly zooplankton (Limacina, amphipods, copepods, and euphausiids), squid, and fish. Except for sockeye, there were no differences in contents related to fish size or state of maturity. Differences were found between species in the kinds of stomach contents present. The predominant organisms were amphipods and fish in pink salmon, crustaceans in immature sockeye, euphausiids and squid in maturing sockeye, euphausiids, fish, and squid in coho, and fish and squid in steelhead stomachs. The stomach contents of chum salmon were notable in that most of their contents were too well digested to identify. Comparison with the findings of workers in the northwestern Pacific showed no significant differences in the kinds of stomach contents, however, a greater amount of material was present in the stomachs they examined. The contents of stomachs from fish taken in various ocean domains were compared. Greater differences were noted in the stomach contents of fish from different domains than from different species. It is suggested that feeding is associated more with availability rather than with preferences for specific organisms.

Trudy VNIRO ◽  
2020 ◽  
Vol 179 ◽  
pp. 90-102
Author(s):  
M. N. Gorokhov ◽  
V. V. Volobuev ◽  
I. S. Golovanov

There are two main areas of pacific salmon fishing in the Magadan region: Shelikhova Gulf and Tauiskaya Bay. The main fishing species is pink salmon in the region. Its share of total salmon catch by odd-year returns reaches 85 %. Data on the dynamics of escapement to the spawning grounds of pink salmon of the Shelikhova Gulf and Tauiskaya Bay are presented. The displacement of the level of spawning returns of pink salmon into the Shelihova Gulf with the simultaneous reduction of its returns to the Tauiskaya Bay is shown. Data on the dynamics of the fishing indicators of pink salmon for the two main fishing areas are provided. The Tauiskaya Bay as the main pink salmon fishery area loses its importance is shown. Graphical data on the escapement of producers pink salmon to the spawning grounds are presented and the optimal values of spawning escapements are estimated. Chum salmon is the second largest and most fishing species. Information on the dynamics of the number of returns, catch and escapement to the spawning grounds of chum salmon is given. The indicators of escapement to the spawning areas and their compliance with the optimal passes of salmon producers are analyzed. The issues of the dynamics of returns number, catch and the escapement to the spawning grounds of coho salmon producers are considered. The level of the escapement to the spawning areas is shown and the ratio of actual to optimal values of passes is estimated. The role of coho salmon as an object of industrial fishing and amateur fishing is shown. The extent of fishing press on individual groups of salmon populations is discussed. It is concluded that it is necessary to remove the main salmon fishery from the Tauiskaya Bay to the Shelikhova Gulf.


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.


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

1973 ◽  
Vol 30 (7) ◽  
pp. 1003-1008 ◽  
Author(s):  
V. W. Kaczynski ◽  
R. J. Feller ◽  
J. Clayton ◽  
R. J. Gerke

Pink and chum salmon (Oncorhynchus gorbuscha and O. keta) fry and Clarke–Bumpus plankton tows were collected from three beach areas in Puget Sound in spring 1970. Chum fry and benthic pump samples were taken in 1971. The diets of the young of the two species were similar. Epibenthic harpacticoid copepods were the chief prey of the chum and pink salmon (57 and 36%, respectively, in 1970). Distinct differences were apparent, the more notable being the preference for invertebrate eggs exhibited by the pinks and the higher preferences for small gammarid amphipods and harpacticoids exhibited by the chums. The stomach contents showed no resemblance to the plankton hauls taken in the same area. The onshore stage of development appears to be a distinct ecological stage in the life cycles of these species.


2006 ◽  
Vol 84 (4) ◽  
pp. 527-536 ◽  
Author(s):  
Z. Li ◽  
A.K. Gray ◽  
M.S. Love ◽  
T. Asahida ◽  
A.J. Gharrett

The Sebastes Cuvier, 1829 subgenus Pteropodus Eigenmann and Beeson, 1893 includes six species from the northeastern Pacific Ocean (NEP) and four species from the northwestern Pacific Ocean (NWP). Several NEP species assigned to other subgenera are similar to NEP Pteropodus species. Restriction site variation in the mitochondrial NADH dehydrogenase subunit 3 and 4 genes and the 12S and 16S ribosomal RNA genes were used to evaluate their relationships. Phylogenetic reconstruction showed that six NEP species of Pteropodus formed a monophyletic group that also included three NEP species currently assigned to other subgenera: Sebastes atrovirens (Jordan and Gilbert, 1880) (subgenus Mebarus Matsubara, 1943) and Sebastes auriculatus Girard, 1854 and Sebastes dalli (Eigenmann and Beeson, 1894) (both subgenus Auctospina (Eigenmann and Beeson, 1894)). The small average nucleotide divergence (0.0124 per nucleotide) observed among members of this group of species was similar to that observed among species of the monophyletic subgenus Sebastomus Gill, 1864 (0.0089 per nucleotide). The NWP species of Pteropodus did not cluster with their NEP consubgeners but, generally, were similar to other NWP species. We recommend that S. atrovirens, S. auriculatus, and S. dalli be included in subgenus Pteropodus with the other NEP species and that the NWP species of Pteropodus be removed from the subgenus. Our results indicate that the morphological characteristics used to distinguish species often may not be useful for phylogenetic analysis.


1985 ◽  
Vol 42 (4) ◽  
pp. 659-668 ◽  
Author(s):  
N. Brent Hargreaves ◽  
Robin J. Lebrasseur

Predation on juvenile pink salmon (Oncorhynchus gorbuscha) and chum salmon (O. keta) by yearling coho (O. kisutch) was studied in marine enclosures in Masset Inlet, B.C. These experiments demonstrate that coho prey selectively upon pink salmon even when chums are both significantly smaller and more abundant than pink salmon. Reexamination of the results of similar experiments conducted in Burke Channel, B.C., also confirms that mortality was biased towards pink salmon. Prey species may be more important than prey size for coho that prey upon mixed populations of pink and chum salmon during early sea-life.


2017 ◽  
Vol 146 (2) ◽  
pp. 240-251 ◽  
Author(s):  
A. F. Muttray ◽  
D. Sakhrani ◽  
J. L. Smith ◽  
I. Nakayama ◽  
W. S. Davidson ◽  
...  

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