An Introduction to the Concept and Application of Marine Protected Areas. Michael J. Fogarty 1

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1 An Introduction to the Concept and Application of Marine Protected Areas Michael J. Fogarty 1 National Marine Fisheries Service Northeast Fisheries Science Center 166 Water St. Woods Hole, MA USA Introduction Marine conservation and resource management addresses multiple objectives including preservation of biodiversity and ecosystem integrity, habitat protection, and sustainable resource use. The potential utility of marine protected areas, defined here as ÒAny area of the coastal zone or open ocean conferred some level of protection for the purpose of management of use of resources or protection of vulnerable or threatened habitats or speciesó (Agardy 1997), has received substantial recent attention as a management tool. Particular emphasis has been placed on Ôno-takeÕ zones (NTZs) in which all extractive activities are prohibited. In addition to helping to ensure sustainability and the maintenance of intact marine ecosystems, protected areas can serve as undisturbed areas for research and as important sites for the aesthetic appreciation of natural systems. The direct and indirect effects of fishing practices on marine ecosystems have elicited concern dating back to at least the 14th century (Anon. 1921). In 1366, a petition was placed to ban the Wondyrchoun, a type of dredge, before the Commons in Britain. It was noted that this gear pressed Ò...so hard on the ground when fishing that it destroys the... plants growing on the bottom under the water, and also the spat of oysters, mussels, and other fish, by which the large fish are accustomed to live and be nourishedó. In 1499, the use of trawls was prohibited in Flanders because Ò... the trawl scraped and ripped up everything it passed over in such a way that it rooted up and swept away the seaweeds which served to shelter the fish; it robbed the beds of their spawn or fry...ó. The Dutch banned the use of trawls in 1583 and trawling was made a capital offense in France in In 1631 in Britain, the use of Ò...traules [was] forbidden as well as of other nets which shall not have the meshes of the size fixed by law and orders...ó. The impact of different types of fishing gears on marine ecosystems remains an important source of concern. Marine reserves hold the potential to eliminate negative impacts of fishing gears and practices in specified areas. In the following, aspects of the motivation for establishment of marine reserves, design considerations, and reserve performance are described. The implications for resource management are accorded particular attention. 1

2 Why Marine Protected Areas? Consideration of the production potential of marine fisheries and recent trends in global catch levels suggest that we are near or have exceeded the limits to overall yield from coastal and continental shelf regions of the world ocean. Estimates of the production capacity of the oceans lead to estimates of global catch limits on the order of 100 million t from nearshore and continental shelf regions of the world. Reported landings have approached this level in the last decade. A recent evaluation of the global status of fishery resource species lists 21% as moderately exploited, 47% as fully exploited with no capacity for increase, 18% as overexploited, 9% as depleted and 4% as underexploited (FAO 2001). Over-capacity of world fishing fleets has placed excessive stress on the productivity of marine resources while reducing the profitability of global fishing enterprises. Expansion of the species under exploitation and fishing at the limits to sustainable production clearly increases the risk of interference with ecosystem processes and functions. Escalation of fishing pressure and increased recognition of problems associated with incidental catch, disruption of food web structure, and habitat disturbance by fishing gear has underscored the need for a more holistic approach to management based on ecosystem principles. Marine reserves, used in conjunction with other management measures, can potentially address fundamental issues in the development of ecosystembased management strategies. In particular, no-take zones hold the potential of reducing fishing mortality on target species, preventing habitat disturbance, protecting non-target organisms, and preserving biodiversity. The effectiveness of marine reserves in meeting these different objectives in specific situations will depend critically on life history characteristics of the species involved, oceanographic features, and the level of compliance and enforcement. Failures in management can be linked to conflicting conservation, economic and social goals and uncertainties due to incomplete knowledge of marine populations, communities and ecosystems. The broader application of no-take marine reserves may serve as a hedge against uncertainty in our understanding (Bohnsack 1996; Murray et al. 1999) and in implementing controls on fishing pressure (Lauck et al. 1998). However, uncertainty associated with critical factors in reserve performance, particularly concerning dispersal rates and processes, can it be considerable and cannot be ignored. Regulations specifying temporal and/or spatial closures of fishing grounds with the objective of protecting juvenile fish, nursery grounds, and spawning aggregations have an extensive history and remain widely employed in marine fishery management, often in concert with other management approaches such as quotas, effort limitations and gear regulations. Virtually all management systems for artisanal fisheries employed restrictions on the time and place of harvest. The current emphasis on no-take marine reserves extends the more traditional forms of fishery closures to encompass broader objectives, more inclusive levels of protection, and broader time horizons. 2

3 Potential benefits of marine reserves (Fogarty et al. 2000; adapted from Bohnsack 1996) include: Fishery-related E Increase abundance, average size of target organisms, reproductive output, and genetic diversity within the reserve E Enhance fishery yield in adjacent grounds E Provide simple and effective management tool which is readily understood and enforced E Guard against uncertainty and reduce probability of overfishing and fishery collapse E Protect rare and valuable species E Provide opportunities for increased understanding of exploited marine systems E Provide basis for ecosystem management General E Increase species diversity and community stability E Increase habitat quality E Provide scientific control sites and undisturbed monitoring sites for assessing human impacts E Create or enhance non-extractive uses including tourism E Reduce user conflicts E Improve public awareness, education, and understanding E Create areas with intrinsic value Design of Marine Reserves Design considerations for marine reserves and networks include specification of the individual size, configuration, placement and number of reserves. The most appropriate design for reserves and/or network of reserves depends on the specific objectives for their establishment. Critical considerations for the development of marine reserves include the recognition of potentially wide dispersal characteristics of many marine organisms and the importance of environmental variability on a broad range of time scales. Guidelines for successful reserve design (Fogarty et al. 2000; adapted from Murray et al. 1999) include: E Clearly specify the goals, objectives, and expectations for the reserve including the species, communities, and habitats to be protected and the role of the reserve within a network (if appropriate). E Choose reserves to represent a broad spectrum of (a) environmental conditions, (b) habitat types and quality (c) biotic communities, (d) oceanographic features including 3

4 current systems, upwelling zones, and retentive features (e) depth and latitude within biogeographic regions, and (f) levels of human impact. E Design reserves to match the scale of ecological and oceanographic processes. Reserves should be sufficiently large to be self sustaining and to minimize edge effects. Placement of reserves within networks should consider dispersal and transport among sites in oceanographic features E Replicate reserves of similar habitat types and biotic communities as a hedge against local catastrophic events at any one individual site and to allow effective and statistically valid evaluation of reserve performance. E Apply principles of adaptive management in reserve design and evaluation and retain flexibility to accommodate changing conditions Understanding and quantifying the dispersal characteristics of marine populations at different life history stages remains the most difficult and challenging issue in marine reserve design. If a reserve is to be self-sustaining, then careful attention to dispersal patterns is essential. Consideration of the reproductive strategies and behavior of the target organisms and the oceanographic features in the vicinity of the reserve is critical. The probability of retention of eggs and larvae within the reserve is a function of the mode of reproduction, duration of early life stages, stage-specific characteristics and behavior (demersal or pelagic eggs, depth preferences and locomotion of larvae, etc.), and oceanographic features affecting transport, retention, and loss. For certain dispersal patterns, it may be necessary to design networks of reserves linked by interchange at one or more life stages. General guidelines for the size of marine reserves depend on the specific objectives for their establishment. Critical issues in deciding the required size and configuration for reserves include consideration of the mean dispersal distance at different life history stages for the target species, edge effects and the perimeter to area ratio, species/area relationships and other factors. For certain fishery management objectives, the issue is more properly framed as protecting a certain proportion of the adult biomass of a stock than protecting a specified proportion of the area within a region. For other objectives, protecting designated habitat types and or representative communities may be most important, particularly for rare or otherwise endangered species, habitats, or communities. It has been recommended that at least 20% of the seabed be set aside in no-take reserves to preserve a minimum population size for exploited species. Fogarty et al. (2000) review the background for this recommendation and note that in fact considerable species and area-specific variation exists in the requisite size of reserves to meet the objective of preserving a minimum biomass. Estimates of the reserve size needed for optimal exploitation range from 35-75% depending on the model structures employed and underlying assumptions (reviewed in Fogarty et al. 2000). (Lauck et al. 1998) reported that reserves of at least 50% of the area would be necessary as a hedge against uncertainty in a system in which exploitation rates could not be carefully controlled. 4

5 Experience with Marine Reserves The experience with established marine reserves holds important lessons for MPA design and monitoring. Examination of changes within reserve boundaries is relatively straightforward; however, determination of the effects of the reserve through spill-over of juveniles and adults or export of eggs and larvae is far more challenging. Consideration of the potential effectiveness of marine reserves for fishery management purposes is necessarily centered on these issues. A reserve that does not contribute to the productivity of areas open to harvest through some level of dispersal at one or more life stages, cannot enhance yield or resilience in these areas. In some instances, it may be feasible to use rotating harvest schemes in which areas are sequentially opened and closed if habitat damage is not a factor. Increases in biomass, mean size, and reproductive output within reserve boundaries have been shown in a number of studies of (see reviews in Dugan and Davis, 1993; NRC 1999; Halpern in press). Dugan and Davis (1993) reported that 24 of 31 studies showed increases in abundance within reserve boundaries. Fogarty et al. (2000) reviewed an additional 36 studies which indicated general increases in abundance and mean size within reserve boundaries. In sixteen of these studies, it was possible to assess changes in reproductive output; in all cases, an increase was reported. In six out of eight cases in which recruitment could be assessed, an increase was reported. Increases in species richness were reported in each of nine studies which examined this issue. Halpern (in press) demonstrated increased abundance, biomass and mean size within reserve boundaries in an assessment of the performance of no-take marine reserves. Fewer studies have assessed the impacts of reserves on yield in adjacent areas. If the 37 studies reviewed by Fogarty et al. (2000), eight examined the question of fisheryeffects and, of these, seven reported increases in yield outside the reserve. Roberts et al. (2001) show that fish yields increased in St. Lucia in areas adjacent to long term reserves and that the occurrence of trophy-size fish in Florida near the Merritt Island National Wildlife Refuge. The ultimate success in the development, implementation and success of marine reserves will depend greatly on social considerations such as the perceived impacts on user groups of the reserve and on levels of compliance and enforcement. Effective communication and consultation with those potentially affected by the placement of the reserve will be essential in reducing conflict and resistance. 5 Conclusion Marine reserves have shown considerable promise as management tools when used in concert with other strategies to control fishing pressure. In particular, the potential to meet multiple conservation and resource management objects through the use of reserves deserves careful attention. Key sources of uncertainty in the effectiveness of reserves

6 relate to difficulties in quantifying dispersal process and exchange rates for different life stages. The effects of reserves in increasing abundance, biomass, and mean size within reserve boundaries are now well established and evidence for positive effects on adjacent fisheries has emerged in recent studies. References Agardy, M.T Marine Protected Areas and Ocean Conservation Academic Press. San Diego CA. Anon The history of trawling: Its rise and development from the earliest times to the present day. Fish. Trades Gaz. 21. Bohnsack, J.A Maintenance and recovery of reef fishery productivity. In (Poulinin, N.V.C. and C.M. Roberts) Reef Fisheries. Chapman and Hall. London. pp Dugan, J.E. and G.E. Davis Introduction to the international symposium on marine harvest refugia. Can. J. Fish. Aquat. Sci. 50: FAO The state of the world fisheries and aquaculture. United Nations, FAO, Rome. Fogarty, M.J., J.A. Bohnsack, and P.K. Dayton Marine reserves and resource management. In (C. Sheppard, Ed.) Seas at the Millenium: An Environmental Evaluation, Volume III, Elsevier, pp Halpern, B. The impact of marine reserves: Do reserves work and does reserve size matter? Ecol. Appl. In press. Lauck. T., C.W. Clark, M. Magel, and G.R. Munro Implementing the precautionary principle in fisheries management through marine reserves. Ecol Appl. 8 (Suppl.) S72-S78. Murray, S.N. and 18 co-authors No-take reserves networks: sustaining fishery populations and marine ecosystems. Fisheries 11:25. Roberts, C., J.A. Bohnsack, F. Gell, J.P. Hawkins, and R. Goodridge Effects of Marine Reserves on Adjacent Fisheries. Science 294: