How does species association affect mixed stock fisheries management? A comparative analysis of the effect of marine protected areas, discard bans, and individual fishing quotas

We developed a spatially explicit bioeconomic model of a mixed-stock fishery with an unproductive and a productive stock to examine how the spatial overlap between species affects the outcome of a fishery under alternative management methods. We considered a competitive total allowable catch (TAC) system, with and without a ban on discards, and an individual vessel quota (IVQ) fishery managed either to maximum sustainable yield (MSY) or maximum economic yield (MEY). We also evaluated the utility of marine protected areas (MPAs) designed to protect the unproductive species for each management scenario. Banning discarding (whether under a TAC or IVQ) created the biggest increase in profit regardless of species overlap as it moves the target species biomass toward Bmey. MPAs reduced the profit in most cases and were not always successful at conserving the unproductive stock above a target size. The IVQ system managed to MEY produced the most profit among all scenarios while preserving the populations above some target values in most cases, but an IVQ system managed to MSY produced lower profits than a competitive TAC with a discard ban at some levels of species overlap.

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Integrating marine protected areas with catch regulation

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f05-243 ◽

2006 ◽

Vol 63 (3) ◽

pp. 642-649 ◽

Cited By ~ 102

Author(s):

Ray Hilborn ◽

Fiorenza Micheli ◽

Giulio A De Leo

Keyword(s):

Protected Areas ◽

Marine Protected Areas ◽

Larval Dispersal ◽

Single Species ◽

Maximum Sustainable Yield ◽

Fish Stock ◽

Total Allowable Catch ◽

Fish Stocks ◽

The Impact ◽

Stock Abundance

Previous models of marine protected areas (MPAs) have generally assumed that there were no existing regulations on catch and have frequently shown that MPAs, by themselves, can be used to maintain both sustainable fish stocks and sustainable harvests. We explore the impact of implementing an MPA in a spatially structured model of a single-species fish stock that is regulated by total allowable catch (TAC). We find that when a stock is managed at maximum sustainable yield, or is overfished, implementation of an MPA will require a reduction in TAC to avoid increased fishing pressure on the stock outside the MPA. In both cases, catches will be lower as a result of overlaying an MPA on existing fisheries management. Only when the stock is so overfished that it is headed towards extinction does an MPA not lead to lower catches. In a TAC-regulated fishery, even if the stock is overfished, MPA implementation may not improve overall stock abundance or increase harvest unless catch is simultaneously reduced in the areas outside the MPA. Models that consider differential adult and larval dispersal need to be explored to see if these results are found with the more complex biology of a two-stage model.

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MARINE CAPTURE FISHERIES POLICY FORMULATION AND THE ROLE OF MARINE PROTECTED AREAS AS TOOL FOR FISHERIES MANAGEMENT IN INDONESIA

Marine Research in Indonesia ◽

10.14203/mri.v30i0.422 ◽

2018 ◽

Vol 30 ◽

pp. 33-45

Author(s):

D. G.R. Wiadnya ◽

P. J. Mous ◽

R. Djohani ◽

M. V. Erdmann ◽

A. Halim ◽

...

Keyword(s):

Protected Areas ◽

Marine Protected Areas ◽

Scientific Evidence ◽

Code Of Conduct ◽

Fishing Effort ◽

Policy Formulation ◽

Maximum Sustainable Yield ◽

Fish Stocks ◽

Fisheries Policy

The FAO Code of Conduct for Responsible Fisheries states that conservation and management decisions for fisheries should be based on the best scientific evidence available. Studies show that most of Indonesia's capture fisheries are either full or over-exploited. However, the fishery sector is still expected to contribute to the increase of Indonesia's GNP through an increase in total catches. Furthermore, the current practice of using catch-effort data and Maximum Sustainable Yield models to inform Indonesia’s fisheries policies is flawed, putting sustainability and long-term profitability of Indonesia's fisheries at risk. In this paper, the authors argue that to ensure the survival of Indonesia's fish stocks and fisheries: fisheries policy must shift from development-oriented management towards management for sustainability. Furthermore, fisheries managers must accept that 'untapped resources' may not exist or cannot be exploited profitably, and that any transfer of fishing effort between fishing grounds may contribute to collapse of local fisheries. Also, fisheries managers should change the management paradigm from MSY models to eco-system based management, wherein Marine Protected Areas should play an important role.

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