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The effects of survey design and circulation pattern on the perceived abundance of herring larvae: a case study for Norwegian spring spawning herring ( Clupea harengus )
Author(s) -
STENEVIK ERLING K.,
NASH RICHARD D.M.,
VIKEBØ FRODE,
FOSSUM PETTER,
BAKKEPLASS KJELL
Publication year - 2012
Publication title -
fisheries oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 80
eISSN - 1365-2419
pISSN - 1054-6006
DOI - 10.1111/j.1365-2419.2012.00631.x
Subject(s) - clupea , herring , abundance (ecology) , fishery , atlantic herring , norwegian , larva , spring (device) , environmental science , oceanography , ecology , biology , geology , mechanical engineering , linguistics , philosophy , fish <actinopterygii> , engineering
A larval survey is used in the annual assessment as an index of the spawning stock size of Norwegian spring spawning herring ( Clupea harengus ). To test how inter‐annual fluctuations in circulation pattern, survey design and execution of the survey affected the larval abundance estimate we conducted simulated surveys using a model framework with idealized assumptions to model larval drift and sampled larvae using several realistic survey scenarios. The results suggest that inter‐annual variations in circulation pattern alone can have a profound effect on the perception of larvae abundance and that the direction of the survey (north to south versus south to north) can have a significant effect on the estimated abundance, particularly if hatching occurs over a short period of time. Additionally, disruptions to a continuous survey schedule also have an effect and, as such, sampling strategies in case of disruption to the survey are proposed.