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Marine reserve effects on fishery profit.

White C, Kendall BE, Gaines S, Siegel DA, Costello C - Ecol. Lett. (2008)

Bottom Line: We incorporated this effect into a bioeconomic model to evaluate the economic performance of reserve-based management.Our results indicate that reserves can still benefit fisheries, even those targeting species that are expensive to harvest.Furthermore, reserve area and harvest intensity can be traded off with little impact on profits, allowing for management flexibility while still providing higher profit than attainable under conventional management.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA 93106, USA.

ABSTRACT
Some studies suggest that fishery yields can be higher with reserves than under conventional management. However, the economic performance of fisheries depends on economic profit, not fish yield. The predictions of higher yields with reserves rely on intensive fishing pressures between reserves; the exorbitant costs of harvesting low-density populations erode profits. We incorporated this effect into a bioeconomic model to evaluate the economic performance of reserve-based management. Our results indicate that reserves can still benefit fisheries, even those targeting species that are expensive to harvest. However, in contrast to studies focused on yield, only a moderate proportion of the coast in reserves (with moderate harvest pressures outside reserves) is required to maximize profit. Furthermore, reserve area and harvest intensity can be traded off with little impact on profits, allowing for management flexibility while still providing higher profit than attainable under conventional management.

Show MeSH
Stock effect curve(s) estimating marginal cost relative to local fish population density. (a) Schematic representation of the calculation of fishery profit at one location during a single harvest season, as a function of revenue based on a fixed market price ($1) per fish unit, minus the sum of the marginal costs of harvesting down the local fish population. In this example the fishery harvested to the ‘zero marginal profit’ level, where (marginal revenue)/(marginal cost) = 1. (b) Stock effect curves representing fishery species that are of different marginal costs to harvest. Increasing values of θ represent fishery species that are intrinsically more expensive to harvest.
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fig01: Stock effect curve(s) estimating marginal cost relative to local fish population density. (a) Schematic representation of the calculation of fishery profit at one location during a single harvest season, as a function of revenue based on a fixed market price ($1) per fish unit, minus the sum of the marginal costs of harvesting down the local fish population. In this example the fishery harvested to the ‘zero marginal profit’ level, where (marginal revenue)/(marginal cost) = 1. (b) Stock effect curves representing fishery species that are of different marginal costs to harvest. Increasing values of θ represent fishery species that are intrinsically more expensive to harvest.

Mentions: Profit to a fishery is a function of revenue gained from selling fish yield, minus the cost of catching those fish. We modelled the marginal cost of fishing to be inversely proportional to local fish density, θ/(fish*km−1) (Clark 1990), where higher values of θ represent species that are intrinsically more expensive to harvest. For each 1-km distance bin along the coast, the annual cost of harvesting was calculated by integrating along the stock effect curve from the pre-harvest to post-harvest population density (Fig. 1a). We then subtracted local cost from local revenue, based on a fixed market price of $1 per fish, and averaged across the entire coastline to estimate mean profit ($*km−1). To highlight the difference between reserve based, and conventional fisheries management, we examined sustainable profit, and thus implicitly assumed zero discounting.


Marine reserve effects on fishery profit.

White C, Kendall BE, Gaines S, Siegel DA, Costello C - Ecol. Lett. (2008)

Stock effect curve(s) estimating marginal cost relative to local fish population density. (a) Schematic representation of the calculation of fishery profit at one location during a single harvest season, as a function of revenue based on a fixed market price ($1) per fish unit, minus the sum of the marginal costs of harvesting down the local fish population. In this example the fishery harvested to the ‘zero marginal profit’ level, where (marginal revenue)/(marginal cost) = 1. (b) Stock effect curves representing fishery species that are of different marginal costs to harvest. Increasing values of θ represent fishery species that are intrinsically more expensive to harvest.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2268951&req=5

fig01: Stock effect curve(s) estimating marginal cost relative to local fish population density. (a) Schematic representation of the calculation of fishery profit at one location during a single harvest season, as a function of revenue based on a fixed market price ($1) per fish unit, minus the sum of the marginal costs of harvesting down the local fish population. In this example the fishery harvested to the ‘zero marginal profit’ level, where (marginal revenue)/(marginal cost) = 1. (b) Stock effect curves representing fishery species that are of different marginal costs to harvest. Increasing values of θ represent fishery species that are intrinsically more expensive to harvest.
Mentions: Profit to a fishery is a function of revenue gained from selling fish yield, minus the cost of catching those fish. We modelled the marginal cost of fishing to be inversely proportional to local fish density, θ/(fish*km−1) (Clark 1990), where higher values of θ represent species that are intrinsically more expensive to harvest. For each 1-km distance bin along the coast, the annual cost of harvesting was calculated by integrating along the stock effect curve from the pre-harvest to post-harvest population density (Fig. 1a). We then subtracted local cost from local revenue, based on a fixed market price of $1 per fish, and averaged across the entire coastline to estimate mean profit ($*km−1). To highlight the difference between reserve based, and conventional fisheries management, we examined sustainable profit, and thus implicitly assumed zero discounting.

Bottom Line: We incorporated this effect into a bioeconomic model to evaluate the economic performance of reserve-based management.Our results indicate that reserves can still benefit fisheries, even those targeting species that are expensive to harvest.Furthermore, reserve area and harvest intensity can be traded off with little impact on profits, allowing for management flexibility while still providing higher profit than attainable under conventional management.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA 93106, USA.

ABSTRACT
Some studies suggest that fishery yields can be higher with reserves than under conventional management. However, the economic performance of fisheries depends on economic profit, not fish yield. The predictions of higher yields with reserves rely on intensive fishing pressures between reserves; the exorbitant costs of harvesting low-density populations erode profits. We incorporated this effect into a bioeconomic model to evaluate the economic performance of reserve-based management. Our results indicate that reserves can still benefit fisheries, even those targeting species that are expensive to harvest. However, in contrast to studies focused on yield, only a moderate proportion of the coast in reserves (with moderate harvest pressures outside reserves) is required to maximize profit. Furthermore, reserve area and harvest intensity can be traded off with little impact on profits, allowing for management flexibility while still providing higher profit than attainable under conventional management.

Show MeSH