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Modeling connectivity of walleye pollock in the Gulf of Alaska: Are there any linkages to the Bering Sea and Aleutian Islands?

TitleModeling connectivity of walleye pollock in the Gulf of Alaska: Are there any linkages to the Bering Sea and Aleutian Islands?
Publication TypeJournal Article
Year of Publication2016
AuthorsParada, C, Hinckley, S, Horne, J, Mazur, M, Hermann, A, Curchister, E
JournalDeep Sea Research Part II: Topical Studies in Oceanography
Volume132
Pagination227 - 239
ISSN0967-0645
KeywordsStock structure
Abstract

Abstract We investigated the connectivity of walleye pollock in the Gulf of Alaska (GOA) and linkages to the Bering Sea (BS) and Aleutian Island (AL) regions. We used a spatially-explicit Individual-based model (IBM) coupled to 6 years of a hydrodynamic model that simulates the early life history of walleye pollock in the \{GOA\} (eggs to age-0 juveniles). The processes modeled included growth, movement, mortality, feeding and the bioenergetics component for larvae and juveniles. Simulations were set to release particles on the 1st of the month (February to May) in fourteen historical spawning areas in the \{GOA\} up to the 1st of September each year. Model results reproduced the link between the Shelikof Strait spawning area and the Shumagin nursery region for March and April spawners, besides other Potential Nursery Areas (PNAs) found in the GOA. A prominent finding of this study was the appearance of the \{BS\} as important \{PNAs\} for several \{GOA\} spawning grounds, which is supported by a consistent flow into the \{BS\} through Unimak Pass. The simulations showed the highest density of simulated surviving pollock in the western Bering Sea (WBS) region with the lowest coefficients of variation of the whole domain. Three spawning sectors were defined, which aggregate multiple spawning areas in the eastern (EGOA), central (CGOA) and western Gulf of Alaska (WGOA). A connectivity matrix showed strong retention within the \{CGOA\} (25.9%) and \{EGOA\} (23.8%), but not in the \{WGOA\} (7.2%). Within the GOA, the highest connectivity is observed from \{EGOA\} to \{CGOA\} (57.8%) followed by the connection from \{CGOA\} to \{WGOA\} (24.3%). Overall, one of the most prominent connections was from \{WGOA\} to \{WBS\} (62.8%), followed by a connection from \{CGOA\} to \{WBS\} (29.2%). In addition, scenarios of shifting spawning locations and nursery sectors of GOA, \{BS\} and \{AL\} are explored and implications for walleye pollock stock structure hypotheses are discussed.

URLhttp://www.sciencedirect.com/science/article/pii/S0967064515004415
DOI10.1016/j.dsr2.2015.12.010