Chum salmon (Oncorhynchus keta) growth and temperature indices as indicators of the year-class strength of age-1 walleye pollock (Gadus chalcogrammus) in the eastern Bering Sea

2015 ◽  
Vol 24 (3) ◽  
pp. 242-256 ◽  
Author(s):  
Ellen M. Yasumiishi ◽  
Keith R. Criddle ◽  
Nicola Hillgruber ◽  
Franz J. Mueter ◽  
John H. Helle
Keyword(s):  
Bering Sea ◽  
Chum Salmon ◽  
Walleye Pollock ◽  
Oncorhynchus Keta ◽  
Chum Salmon Oncorhynchus Keta ◽  
Eastern Bering Sea ◽  
Class Strength ◽  
Temperature Indices

Estimating target strength of young chum salmon (Oncorhynchus keta)

2022 ◽  
pp. 1-5
Author(s):  
Kenji Minami ◽  
Hokuto Shirakawa ◽  
Yohei Kawauchi ◽  
Huamei Shao ◽  
Makoto Tomiyasu ◽  
...  
Keyword(s):  
Bering Sea ◽  
Chum Salmon ◽  
Fork Length ◽  
Target Strength ◽  
Oncorhynchus Keta ◽  
Biomass Estimation ◽  
Fishery Resource ◽  
Chum Salmon Oncorhynchus Keta ◽  
Acoustic Methods ◽  
The Bering Sea

Although chum salmon (Oncorhynchus keta) is an important fishery resource in Japan, acoustic methods cannot be applied to biomass estimation because the target strength (TS) is unknown. This study clarified the TS for each fork length (FL: 5.5–33.5 cm) of young chum salmon inhabiting the Japanese coastal area to the Bering Sea by measuring free-swimming fish. The size dependences of the TS values were TSmean = 20 log10 FL – 68.0, for both 38 and 120 kHz. This facilitated the estimation of biomass of young salmon using acoustic methods.

Climate warming and the loss of sea ice: the impact of sea-ice variability on the southeastern Bering Sea pelagic ecosystem

2020 ◽  
Author(s):  
George L Hunt ◽  
Ellen M Yasumiishi ◽  
Lisa B Eisner ◽  
Phyllis J Stabeno ◽  
Mary Beth Decker
Keyword(s):  
Sea Ice ◽  
Climate Warming ◽  
Bering Sea ◽  
Ice Cover ◽  
Walleye Pollock ◽  
Pelagic Ecosystem ◽  
Eastern Bering Sea ◽  
Calanus Glacialis ◽  
Class Strength ◽  
The Impact

Abstract We investigated relationships among three metrics of sea-ice cover in eight regions of the eastern Bering Sea and the abundance of Calanus copepods, jellyfish medusae, and year-class strength of walleye pollock (Gadus chalcogrammus). In summer, Calanus spp. were more abundant over the middle shelf when sea ice lingered late into spring, and, to a lesser extent, when February sea-ice cover was heavy. Between 1982 and 1999, there were no significant (p ≤ 0.05) relationships between the amount or timing of sea-ice cover and pollock recruitment. However, between 2000 and 2015, pollock year-class strength was positively correlated with sea ice in the outer and middle shelves, with 17 of 24 regressions significant. Pollock year-class strength was best predicted by days with sea-ice cover after February. Pollock recruitment was positively influenced by copepod numbers, particularly in the middle shelf, with r2 values from 0.36 to 0.47. We hypothesize that the Calanus spp. present in the southeastern Bering Sea are primarily Calanus glacialis that have been advected south in association with sea ice. None of our sea-ice metrics explained the variance in jellyfish biomass. Jellyfish biomass in our study area in the pollock age-0 year was not correlated with pollock recruitment 3 years later.

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