Northeast Arctic cod population persistence in the Lofoten-Barents Sea system under fishing.
Population growth, and hence the population's persistence, is affected by several factors such as climate, species interaction, and harvesting pressure. Proper resource management requires an understanding of these factors. We apply techniques based upon age-structured population matrices to analyze estimated stock sizes derived from annual bottom trawl sampling in the winter feeding area of northeast Arctic cod (Gadus morhua L.) from 1981 to 2003. We run generalized additive models to explain population growth rate by different explanatory variables. Cod population growth was found to be positively related to the abundance of capelin (Mallotus villosus Miller), negatively related to the number of cannibalistic cod with a two-year lag, and marginally positively related to the winter North Atlantic Oscillation index (NAO). This model remains true independently from the population status (i.e., fished or non-fished). Capelin abundance is the main variable that to some degree can be adjusted in order to maintain the population size at a given level of cod harvesting. Our results point to the importance of managing conjointly cod and capelin stocks.
Durant
Joël M
JM
Centre for Ecological and Evolutionary Synthesis, Department of Biology, University of Oslo, P.O. Box 1066 Blindern, 0316 Oslo, Norway.
Hjermann
Dag O
DO
Sabarros
Philippe S
PS
Stenseth
Nils Chr
NC
D000818:Animals; D001110:Arctic Regions; D004784:Environmental Monitoring; D005398:Fisheries; D048389:Gadus morhua / Q000502:physiology*; D009664:Norway; D009792:Oceans and Seas; D011157:Population Dynamics; D012426:Russia; D012621:Seasons; D013997:Time Factors