Fishing and the impact of marine reserves in a variable environment

L D Rodwell; C M Roberts

doi:10.1139/F04-142

Fishing and the impact of marine reserves in a variable environment

L D Rodwell, C M Roberts

Environment and Geography

Research output: Contribution to journal › Article › peer-review

Abstract

We use discrete-time models to investigate the impact of marine reserve establishment on fishery catch and biomass levels in open-access and quota-regulated fisheries under conditions of recruitment variability and natural mortality events. We find that under the conditions of variability tested, reserves can increase the probability of achieving target levels of biomass (60%, 35%, and 5% of carrying capacity) and can reduce catch variability in neighbouring fisheries, making future planning in the fishery more efficient. The size of the reserve required to meet each objective will depend on the initial condition of the stock and the exploitation rate in the fishery. Reserve coverage of between 20% and 40% prevent stock collapse in most cases. In heavily exploited fisheries, reserves are also likely to enhance mean catches, particularly in highly variable systems. If the stock has previously been heavily exploited, large reserves (greater than or equal to60%) may be required to significantly increase the probability of achieving target biomass levels. However, once stocks have recovered, reserve coverage may be reduced without a reduction in this probability of success.

Original language	English
Pages (from-to)	2053-2068
Number of pages	16
Journal	Canadian Journal of Fisheries and Aquatic Sciences
Volume	61
Issue number	11
DOIs	https://doi.org/10.1139/F04-142
Publication status	Published - Nov 2004

Bibliographical note

Keywords

FISHERIES MANAGEMENT
BIOECONOMIC MODEL

Access to Document

10.1139/F04-142

robertscm4.pdf

http://pubs.nrc-cnrc.gc.ca/

Cite this

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title = "Fishing and the impact of marine reserves in a variable environment",

abstract = "We use discrete-time models to investigate the impact of marine reserve establishment on fishery catch and biomass levels in open-access and quota-regulated fisheries under conditions of recruitment variability and natural mortality events. We find that under the conditions of variability tested, reserves can increase the probability of achieving target levels of biomass (60%, 35%, and 5% of carrying capacity) and can reduce catch variability in neighbouring fisheries, making future planning in the fishery more efficient. The size of the reserve required to meet each objective will depend on the initial condition of the stock and the exploitation rate in the fishery. Reserve coverage of between 20% and 40% prevent stock collapse in most cases. In heavily exploited fisheries, reserves are also likely to enhance mean catches, particularly in highly variable systems. If the stock has previously been heavily exploited, large reserves (greater than or equal to60%) may be required to significantly increase the probability of achieving target biomass levels. However, once stocks have recovered, reserve coverage may be reduced without a reduction in this probability of success.",

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