Skip to main content
Log in

Lessons for stock assessment from the northern cod collapse

  • Paper
  • Published:
Reviews in Fish Biology and Fisheries Aims and scope Submit manuscript


Fisheries assessment scientists can learn at least three lessons from the collapse of the northern cod off Newfoundland: (1) assessment errors can contribute to overfishing through optimistic long-term forecasts leading to the build-up of overcapacity or through optimistic assessments which lead to TACs being set higher than they should; (2) stock size overestimation is a major risk when commercial catch per effort is used as an abundance trend index, so there is continued need to invest in survey indices of abundance trend no matter what assessment methodology is used; and (3) the risk of recruitment overfishing exists and may be high even for very fecund species like cod. This implies that harvest rate targets should be lower than has often been assumed, especially when stock size assessments are uncertain. In the end, the high cost of information for accurate stock assessment may call for an alternative approach to management, involving regulation of exploitation rate via measures such as large-scale closures (refuges) that directly restrict the proportion of fish available to harvest. Development of predictive models for such regulatory options is a major challenge for fisheries assessment science.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Subscribe and save

Springer+ Basic
EUR 32.99 /Month
  • Get 10 units per month
  • Download Article/Chapter or Ebook
  • 1 Unit = 1 Article or 1 Chapter
  • Cancel anytime
Subscribe now

Buy Now

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others


  • Anon. (1977) Repost of the Standing Committee on Research and Statistics (STACRES). Appendix I, Report of Assessment Subcommittee, p.54. Int. Comm. Northwest Atlantic Fisheries, Redbook 1977. 116pp.

  • Baird, J.W., Bishop, C.A., Brodie, W.B. and Murphy, E.F. (1992) An assessment of the cod stock in NAFO divisions 2J3KL. NAFO Sci. Council Res. Doc. 92/18, Ser. No. N2063.

  • CAFSAC (1987) Canadian Atlantic Fisheries Scientific Advisory Committee, Annual Report for 1986 (Volumn 9). Dartmouth, Canada: Dept Fisheries and Oceans.

    Google Scholar 

  • Cooke, J.G., and Beddington, J.R. (1985) The relationship between catch rates and abundance in fishes. IMA J. Math. Appl. Med. Biol. 2, 1–15.

    Google Scholar 

  • Deriso, R.B. (1987) Optimal F0.1 criteria and their relationship to maximum sustainable yield. Can. J. Fish. aquat. Sci. 44 (Suppl. 2) 339–48.

    Google Scholar 

  • Dugan, J.F. and Davis, G.E. (1993). Applications of marine refugia to coastal fisheries management. Can. J. Fish. aquat. Sci. 50, 2029–42.

    Google Scholar 

  • Finlayson, A. (1994) Fishing for Truth: A Sociological Analysis of Northern Cod Stock Assessments from 1977–1990. St John's Nfld: Inst. Social and Economic Res., Memorial University. 176 pp.

    Google Scholar 

  • Fleming, A.M. (1965) Trends in catch, age, and size of cod from the commercial longline fishery at Bonavista, Newfoundland, 1952–1962. J. Fish. Res. Bd Can., 22, 465–74.

    Google Scholar 

  • Gavaris, S. (1988) An adaptive framework for the estimation of population size. CAFSAC (Can. Atl. Fish. Sci. Adv. Comm.) Res. Doc. 88/29.

  • Grecco, V. and Overholtz W.J. (1990) Causes of density-dependent catchability for Georges Bank haddock (Melanogrammus aeglefinus). Can. J. Fish. aquat. Sci. 47, 385–94.

    Google Scholar 

  • Harris, L. (1990) Independent review of the stae of the northern cod stock. Ottawa: Communications Directorate, Canadian Dept Fisheries and Oceans. 154 pp.

    Google Scholar 

  • Hilborn, R. and Walters C. (1992) Quantitative Fisheries Stock Assessment and Management: Choice, Dynamics, and Uncertainty. New York: Chapman & Hall. 604 pp.

    Google Scholar 

  • Hutchings, J. and Myers, R.A. (1994) What can be learned from the collapse of a renewable resource? Atlantic cod, Gadus Morhua, of Newfoundland and Labrador. Can. J. Fish. aquat. Sci. 51, 2126–46.

    PubMed  Google Scholar 

  • ICES (1988) Report of the workshop on methods of fish stock assessment. Copenhagen, Denmark: Int. Council for the Exploration of the Seas.

    Google Scholar 

  • Lear, W.H. and Parsons, L.S. (1993) History and management of the fishery for northern cod in NAFO Divisions 2J, 3K, and 3L In Parsons, L.S. and Lear, W.H., eds. Perspectives on Canadian marine fisheries management. Can. Bull. Fish. aquat. Sci. No. 226, pp. 55–89.

  • McGuire, T.R. (1991) Science and the destruction of a shrimp fleet. Mar. anthropol. Stud. 4, 32–55.

    Google Scholar 

  • Myers, R.A. and Barrowman, N.J. (1994) Is fish recruitment related to spawner abundance. ICES CM 1994/G: 37, Ref. H.

  • Myers, R.A., Drinkwater, K.F., Barrowman, N.J. and Baird, J.W. (1993) Salinity and recruitment of Atlantic cod (Gadus morhua) in the Newfoundland region. Can. J. Fish. aquat. Sci. 50, 1599–1609.

    Google Scholar 

  • Myers, R.A., Rosenberg, A.A., Mace, P.M., Barrowman, N. and Restrepo, Y.R. (1994) In search of thresholds for recruitment overfishing. ICES J. mar. Sci. 51, 191–205.

    Google Scholar 

  • NAFO (1991) Northwest Atlantic Fisheries Organization, Scientific Council Reports for 1981. Dartmouth, Canada.

  • Patterson, K. (1992) Fisheries for small pelagic species: an empirical approach to management targets. Rev. Fish Biol. Fisheries 2, 321–38.

    Google Scholar 

  • Pauly, D. (1994) On the Sex of Fish and the Gender of Scientists (Fish and Fisheries Series 14). London, UK: Chapman and Hall. 250 pp.

    Google Scholar 

  • Pitcher, T. and Hart, P.J.B. (1982) Fisheries Ecology. London: Chapman and Hall. 414 pp.

    Google Scholar 

  • Restrepo, V.R., Hoenig, J.M., Powers, J.E., Baird, J.W. and Turner, S.C. (1992) A simple simulation approach to risk and cost analysis, with applications to swordfish and cod fisheries. Fishery Bull. 90, 736–48.

    Google Scholar 

  • Rivard, D. (1989) Overview of the systematic, structural and sampling errors in cohort analysis. Am. Fish. Soc. Symp. 6, 49–65.

    Google Scholar 

  • Steele, D.H., Andersen, R. and Green, J.M. (1992) The managed commercial annihilation of northern cod. Newfoundland Stud. 8, 34–68.

    Google Scholar 

  • Swain, D.P. and Sinclair, A.F. (1994) Fish distribution and catchability: what is the appropriate measure of distribution? Can. J. Fish. aquat. Sci. 51, 1046–54.

    Google Scholar 

  • Swain, D.P., Nielsen, G.A., Sinclair, A.F. and Chouinard, G.A. (1994) Changes in catchability of Atlantic cod (Gadus morhua) to an otter trawl fishery and research survey in the southern Gulf of St. Lawrence. ICES J. mar. Sci. (in press).

  • Tobin, B. (1995) Speaking for the fish. Fisheries 20(7), 18–19.

    Google Scholar 

  • Walters, C.J. and Ludwig, D. (1987) Adaptive management of harvest rates in the pressure of a risk averse utility function. Nat. Res. Model. 1, 21–37.

    Google Scholar 

  • Walters, C.J. and Ludwig, D. (1994) Calculation of Bayes posterior probability distributions for key population parameters. Can. J. Fish. aquat. Sci. 51, 713–22.

    Google Scholar 

  • Walters, C.J. and Punt, A. (1994) Placing odds on sustainable catch using virtual population analysis and survey data. Can. J. Fish. aquat. Sci. 51, 946–58.

    Google Scholar 

Download references

Author information

Authors and Affiliations


Rights and permissions

Reprints and permissions

About this article

Cite this article

Walters, C., Maguire, JJ. Lessons for stock assessment from the northern cod collapse. Rev Fish Biol Fisheries 6, 125–137 (1996).

Download citation

  • Accepted:

  • Issue Date:

  • DOI: