Set catch shares by species

How is the evidence assessed?
  • Effectiveness
    not assessed
  • Certainty
    not assessed
  • Harms
    not assessed

Study locations

Key messages

  • One study examined the effects of setting catch shares by species on marine fish populations. The study was in the Pacific Ocean (Canada).






  • Reduction of unwanted catch (1 study): One before-and-after study in the Pacific Ocean found that after a species-specific catch share was set (Individual Vessel Bycatch Quota) unwanted halibut catch in a multi-species fishery was reduced, whereas it was higher under a previous catch share system (Individual Transferable Quota) based on all species in the catch.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

  1. A before-and-after study in 1962–2006 of bottom fishing grounds in the northwest Pacific Ocean off British Columbia, Canada (Edinger & Baek 2015) found that in the 10 years after implementing an individual vessel quota system for unwanted catch (Individual Vessel Bycatch Quota) in a multispecies groundfish fishery, the unwanted catch of Pacific halibut Hippoglossus stenolepis (a prohibited species) was reduced, but a previous quota system limiting the amount of all species in the catch by vessel (Individual Transferrable Quotas) increased halibut catch. In the period 1996–2006 following the introduction of a “bycatch” quota system for individual vessels in 1996, halibut catches fell by 219% (data reported as statistical model results). Conversely, when individual transferrable catch quotas had been implemented in 1990, it resulted in a 40% increase in unwanted halibut catches (data reported as statistical model results). Authors noted that this increase was due to individual transferrable quotas tending to only consider the conservation of a single species rather than multiple species caught at the same time. Fisheries data from the British Columbia groundfish fishery for the period 1962–2006 were analysed, provided by The International Pacific Halibut Commission and Fisheries and Oceans Canada. The British Columbia Groundfish fishery implemented an individual vessel bycatch quota system in 1996 whereby trawl license holders received a quota representing a percentage of the species-specific total allowable catch.

    Study and other actions tested
Please cite as:

Taylor, N., Clarke, L.J., Alliji, K., Barrett, C., McIntyre, R., Smith, R.K., and Sutherland, W.J. (2021) Marine Fish Conservation: Global Evidence for the Effects of Selected Interventions. Synopses of Conservation Evidence Series. University of Cambridge, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

Marine Fish Conservation

This Action forms part of the Action Synopsis:

Marine Fish Conservation
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