Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Proc Natl Acad Sci U S A. 1999 Apr 27;96(9):5066-71.

Cycles and trends in cod populations.

Author information

  • 1Department of Biology, Division of Zoology, University of Oslo, PO Box 1050 Blindern, N-0316 Oslo, Norway. bjornsta@nceas.ucsb.edu

Abstract

Year-to-year fluctuations in fish stocks are usually attributed to variability in recruitment, competition, predation, and changes in catchability. Trends in abundance, in contrast, are usually ascribed to human exploitation and large-scale environmental changes. In this study, we demonstrate, through statistical modeling of survey data (1921-1994) of cod from the Norwegian Skagerrak coast, that both short- and long-term variability may arise from the same set of age-structured interactions. Asymmetric competition and cannibalism between cohorts generate alternating years of high and low abundance. Intercohort interactions also resonate the recruitment variability so that long-term trends are induced. The coupling of age-structure and variable recruitment should, therefore, be considered when explaining both the short- and long-term fluctuations displayed by the coastal cod populations. Resonant effects may occur in many marine populations that exhibit this combination of traits.

PMID:
10220419
[PubMed - indexed for MEDLINE]
PMCID:
PMC21817
Free PMC Article

Images from this publication.See all images (4)Free text

Figure 1
Figure 2
Figure 3
Figure 4
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk