Phenological and geographical patterns of walleye pollock (Theragra chalcogramma) spawning in the western Gulf of Alaska

Lorenzo Ciannelli; Kevin M Bailey; Kung-Sik Chan; Nils Chr Stenseth

doi:10.1139/f07-049

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Phenological and geographical patterns of walleye pollock (Theragra chalcogramma) spawning in the western Gulf of Alaska

Journal article

Peer reviewed

Phenological and geographical patterns of walleye pollock (Theragra chalcogramma) spawning in the western Gulf of Alaska

Lorenzo Ciannelli, Kevin M Bailey, Kung-Sik Chan and Nils Chr Stenseth

Canadian journal of fisheries and aquatic sciences, Vol.64(4), pp.713-722

2007

DOI: 10.1139/f07-049

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Abstract

Over 20 years of egg sampling data were used to reconstruct the geographical and phenological patterns of walleye pollock (Theragra chalcogramma) spawning aggregations in the Gulf of Alaska (GOA). The analyzed time series (1972, 1978-1979, 1981-2000) included a documented event of climate change (i.e., 1988-1989) and the rise and fall of the GOA pollock population abundance and harvests. We compared results from two generalized additive model (GAM) formulations: one assuming no change of egg distribution and phenology over the examined time series (stationary) and the other admitting such changes (nonstationary) across an epoch determined from the data. Results from both model formulations corroborate the existence of a high egg concentration in Shelikof Strait, historically the primary spawning area of pollock in the GOA. However, model results also highlight the presence of other secondary, and possibly transitory, centers of egg distribution at various locations along the shelf and slope regions of the GOA. In addition, results from the nonstationary (and statistically superior) formulation indicate that the abundance of the non-Shelikof aggregations has increased over time, along with a tendency for earlier occurrence and displacement toward shallower areas of the high egg density regions. © 2007 NRC.

Meteorology

Animal, plant and microbial ecology

Applied ecology

Biological and medical sciences

Climatology. Bioclimatology. Climate change

Earth, ocean, space

Exact sciences and technology

Exploitation and management of natural biological resources (hunting, fishing and exploited populations survey, etc.)

External geophysics

Fundamental and applied biological sciences. Psychology

Details

Title: Subtitle: Phenological and geographical patterns of walleye pollock (Theragra chalcogramma) spawning in the western Gulf of Alaska
Creators: Lorenzo Ciannelli - University of Oslo
Kevin M Bailey - NOAA National Marine Fisheries Service Alaska Fisheries Science Center
Kung-Sik Chan - University of Iowa
Nils Chr Stenseth - University of Oslo
Resource Type: Journal article
Publication Details: Canadian journal of fisheries and aquatic sciences, Vol.64(4), pp.713-722
Publisher: National Research Council of Canada
DOI: 10.1139/f07-049
ISSN: 0706-652X
eISSN: 1205-7533
Language: English
Date published: 2007
Academic Unit: Statistics and Actuarial Science; Radiology
Record Identifier: 9984257616502771

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