COMMENT: MARINE RESERVES: WILL THEY ACCOMPLISH MORE WITH MANAGEMENT COSTS?

Hannesson (Marine Resource Economics 13(3) 1998) takes a critical approach to marine protected areas (MPAs) using simulations of MPAs combined with open access. His results show the conservation effect of an MPA of an appropriate size being the same as that achieved with optimal quota regulation, but with a smaller catch. We expand this analysis by adding a management cost function and increasing the fishing costs to a more realistic level. It is shown that the use of MPAs of certain sizes can be a more advantageous management tool than traditional quotas; hence, the inclusion of management costs modifies some of the findings of Hannesson (1998). We also illustrate how sensitive the results are to the choice of fishing cost values, making the attractiveness of private property versus marine reserves much less clear than proposed by Hannesson (1998).Resource /Energy Economics and Policy,

The cost of fisheries induced evolution. An example using data for North-East Atlantic cod

Age and size at maturity are key life-history traits in a fish stock. At the individual level age and size at maturity affect fecundity, growth and survival. At the population level these factors interact to affect age and size distribution, the population dynamics and the productivity of the stock. A maturation reaction norm is a function describing the probability that a certain percentage of the stock has reached maturity at a given age. Recent studies have shown that high levels of fishing mortality may act as a selective force, favoring individuals that mature at an early age and size, causing a negative shift in the reaction norm denoted fishing induced evolution. Reducing the age and size at maturation generates a number of negative effects that may be slow to reverse or even irreversible: In general, somatic growth is dramatically decreased after maturation, implying that as age and size at maturity are driven to lower levels, the stock will consist of smaller individuals. Further, smaller fish have lower fecundity than larger fish, implying a reduction in the number of fish being recruited. Together, these effects may reduce the yield of the stock, increase risk of extinction and have a number of adverse effects on the ecosystem. This paper assess the cost associated with a reduction in maturity at age for cod North-East Atlantic

On the Joint Management of Catch and Bycatch and the Use of Marine Reserves

This paper explores the possibility of using marine reserves to protect stocks subject to bycatch problems. The importance of migration rates and growth rates of both target and bycatch species and costs are analyzed. Pure open access equilibrium harvest of target species and stock level of bycatch species are compared to those generated by a reserve and open access in the harvest zone. Win-win situations, situations where both harvest of target species and stock size of bycatch species increase, are searched for. It is shown that using a reserve to protect a slow moving bycatch species is more likely to be a success than in the case of a fast moving bycatch species. Furthermore, a fast moving species is worse off after the introduction of a reserve if it has an intrinsic growth rate that is lower than the target species, and in some cases a reserve may actually drive the bycatch stock to extinction. No win-win situations are found in the case of a fast moving species. In the case of a slow moving bycatch species a reserve increases stock size and in cases with low unit cost of effort win-win situations are identified.The National Oceanic & Atmospheric Administration Marine Fisheries Service, United States Department of Commerce (NOAA Fisheries); United Kingdom Department for Environment, Food and Rural Affairs (DEFRA); The United States Agency for International Development supported Aquaculture Collaborative Research and Support Program (ACRSP)

Fisheries induced evolution. A review

Age and size at maturity are key life-history traits in a fish stock. At the individual level, age and size at maturity affect fecundity, growth and survival. At the population level these factors interact to affect the age and size distribution, the population dynamics and the productivity of the stock. Recent studies have shown that high levels of fishing mortality may act as a selective force, favoring individuals that mature at an early age and small size. In general, somatic growth is dramatically decreased after maturation, implying that, as age and size at maturity are driven to lower levels, the stock will consist of smaller individuals. Smaller fish have lower fecundity than larger fish, implying a reduction in recruitment rates and a greater exposure to stochastic events. Together, these effects may reduce the yield of the stock, increase risk of extinction and have a number of adverse effects on the ecosystem. The effects of fisheries induced evolution may also be slow to reverse or even irreversible. Hence, both profitability considerations and the precautionary principle call for taking fisheries induced evolution into account when managing fish stocks. This paper reviews theoretical and empirical work on fishery induced evolution, focusing on management practices that may reduce the evolutionary impact of harvesting

The Economics of MPAs Revisited

Assuming a broad set of management goals, we analyze the implementation of a marine protected area (MPA) together with open access by applying a bioeconomic model that ensures unchanged growth post-MPA. Taking into account that conservation and restoration, food security, employment and social surplus are amongst the objectives that many managers include in fisheries management, we find that this broader approach to MPAs may well recommend them to a greater degree than espoused in the more common resource rent focused studies carried out to date. It is shown that for overfished stocks, an MPA may yield protection, maximize harvests and increase consumer and producer surplus, as well as providing higher employment. This is however less apparent for moderately overfished as well as highly migratory stocks.Keywords: Fisheries Management, Governance: Marine Reserves and Protected Areas Part I, Fisheries EconomicsKeywords: Fisheries Management, Governance: Marine Reserves and Protected Areas Part I, Fisheries Economic

Quotas, marine reserves and fishing the line. When does marine reserve creation pay?

This paper explores the issue of using marine reserves in combination with quotas as fisheries management tools using a patchy environment model as the biological foundation. The rent generated by fishing on the total population, using optimal quotas as a management tool, is compared to the rent from the fishery when managed with quotas and a marine reserve. This is done under different assumptions regarding the type of dispersal mechanisms between the sub-populations in the different patches and under two different assumptions regarding the harvest function. It is shown that the profitability of reserve creation depends on the migration rate relative to the intrinsic growth rate and the cost / price ratio and that the choice of harvesting function is of particular importance when the costs of fishing are high

Productivity in organic and conventional salmon aquaculture

This report provides a comparative analysis of productivity in conventional and organic salmon aquaculture. Regulations in organic salmon farming impose several restrictions on production that are not present in conventional salmon farming. We have analysed the effect of a fish density regulation on the economic performance of salmon farms. A fish density regulation has two possible consequences. First, with a given cage volume, it leads to a reduction in total production at the farm. Second, it leads to an increase in costs per kilo produced. We undertook a linear programming analysis of a conventional salmon farm and organic salmon farms with open and closed cage systems. The results from the analysis indicated strongly that the economic performance is sensitive to the maximum fish density

Bioeconomic Analysis of By-Catch of Juvenile Fish in the Shrimp Fisheries – an Evaluation of Management Procedures in the Barents Sea

A bioeconomic model on the management ofby-catch of juvenile fish in the shrimp fisheryin the Barents Sea and the Svalbard Zone,presented by the Norwegian Directorate ofFisheries to the Joint Norwegian RussianFisheries Commission in 1993, is evaluated. The model is based on management of by-catchthrough closure of areas when the by-catch ofjuvenile fish from commercially importantspecies exceeds a critical number. It isargued that although the model may prove usefulin bringing economic rationale into themanagement of by-catch, care must be taken whenstocks are in poor shape. This is illustratedby using the high mortality rates and low stocklevels experienced for cod and haddock in 2000,and which is expected for the next couple ofyears. It is therefore discussed when it isappropriate to use the model with reference tothe Code of Conduct provided by FAO in 1995. Copyright Kluwer Academic Publishers 2004by-catch, Code of Conduct, shrimp fisheries,

Marine protected areas in a welfare-based perspective

Assuming a broad set of fisheries management goals, this paper analyzes the implementation of a marine protected area (MPA) together with open access outside, applying a bioeconomic model that ensures unchanged growth post-MPA. Taking into account that conservation and restoration, food security, employment and social surplus are amongst the objectives that many managers include in fisheries management, it is found that this broader welfare economic approach to MPAs may well recommend them to a greater degree than espoused in the more common resource rent focused studies carried out to date. It is shown that for overfished stocks, an MPA may yield resource protection, maximize harvests and increase consumer and producer surplus, as well as give higher employment. This, however, is less apparent for moderately overfished as well as highly migratory stocks. Resource protection and enhancement implicitly improves ecosystem services