Uncrewed surface vehicle survey of walleye pollock, Gadus chalcogrammus, in response to the cancellation of ship-based surveys

2021 ◽  
Vol 150 (4) ◽  
pp. A254-A255
Author(s):  
Alex De Robertis ◽  
Mike Levine ◽  
Nathan Lauffenburger ◽  
James Ianelli ◽  
Cole Monnahan ◽  
...  
Keyword(s):  
Walleye Pollock

Effect of Water Temperature on the Egg Hatch and Early Growth of Walleye Pollock (Gadus chalcogrammus)

2020 ◽  
Vol 32 (2) ◽  
pp. 78-83
Author(s):  
Jin Choi ◽  
Gyeong Sik Han ◽  
Ki Wook Lee ◽  
Soon-Gyu Byun ◽  
Hyun Jeong Lim ◽  
...  
Keyword(s):  
Water Temperature ◽  
Early Growth ◽  
Walleye Pollock ◽  
Egg Hatch ◽  
Effect Of Water

scholarly journals Mechanisms of Sound Production in Walleye Pollock Theragra chalcogramma (Pallas).

1995 ◽  
Vol 61 (2) ◽  
pp. 243-244 ◽  
Author(s):  
Yong-Seok Park ◽  
Yasunori Sakurai ◽  
Kohji Iida ◽  
Tohru Mukai
Keyword(s):  
Sound Production ◽  
Walleye Pollock ◽  
Theragra Chalcogramma ◽  
Walleye Pollock Theragra Chalcogramma

scholarly journals Correcting density-dependent effects in abundance estimates from bottom-trawl surveys

2014 ◽  
Vol 71 (5) ◽  
pp. 1107-1116 ◽  
Author(s):  
Stan Kotwicki ◽  
James N. Ianelli ◽  
André E. Punt
Keyword(s):  
Stock Assessment ◽  
Dead Zone ◽  
Walleye Pollock ◽  
Assessment Model ◽  
Bottom Trawl ◽  
Trawl Survey ◽  
Negative Consequences ◽  
Catch Per Unit Effort ◽  
Density Dependent ◽  
Index Of Abundance

Abstract Indices of abundance are important for estimating population trends in stock assessment and ideally should be based on fishery-independent surveys to avoid problems associated with the hyperstability of the commercial catch per unit effort (cpue) data. However, recent studies indicate that the efficiency of the survey bottom trawl (BT) for some species can be density-dependent, which could affect the reliability of survey-derived indices of abundance. A function qe∼f(u), where qe is the BT efficiency and u the catch rate, was derived using experimentally derived acoustic dead-zone correction and BT efficiency parameters obtained from combining a subset of BT catch data with synchronously collected acoustic data from walleye pollock (Theragra chalcogramma) in the eastern Bering Sea (EBS). We found that qe decreased with increasing BT catches resulting in hyperstability of the index of abundance derived from BT survey. Density-dependent qe resulted in spatially and temporarily variable bias in survey cpue and biased population age structure derived from survey data. We used the relationship qe∼f(u) to correct the EBS trawl survey index of abundance for density-dependence. We also obtained a variance–covariance matrix for a new index that accounted for sampling variability and the uncertainty associated with the qe. We found that incorporating estimates of the new index of abundance changed outputs from the walleye pollock stock assessment model. Although changes were minor, we advocate incorporating estimates of density-dependent qe into the walleye pollock stock assessment as a precautionary measure that should be undertaken to avoid negative consequences of the density-dependent qe.

scholarly journals Climate change causing phase transitions of walleye pollock ( Theragra chalcogramma ) recruitment dynamics

2005 ◽  
Vol 272 (1573) ◽  
pp. 1735-1743 ◽  
Author(s):  
Lorenzo Ciannelli ◽  
Kevin M Bailey ◽  
Kung-Sik Chan ◽  
Andrea Belgrano ◽  
Nils Chr Stenseth
Keyword(s):  
Climate Change ◽  
Phase Transitions ◽  
Walleye Pollock ◽  
Theragra Chalcogramma ◽  
Walleye Pollock Theragra Chalcogramma
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