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CONSERVATION GOALS ON LAND AND IN THE SEA
Terrestrial reserves and protected areas have a long history compared to marine protected areas (MPAs) and many lessons can be learned for application to MPAs. Although MPAs will require different design features than terrestrial protected areas, the motivations for creating them are similar and include maintaining essential ecological processes, preserving biological diversity, ensuring the sustainable use of species and ecosystems, and protecting cultural heritage sites.
Differences in approaches to the conservation of marine and terrestrial areas reflect both (1) differences in ecosystem processes and (2) differences in historical perceptions and regulatory frameworks.
Differences Between Marine and Terrestrial Ecosystems
Much of the theory of conservation biology has focused on developing management strategies to protect terrestrial wildlife. However, application of these theories to marine conservation has been debated. The discussion that follows highlights some of the differences that may affect application of terrestrial-based models to conserve marine species.
Marine and terrestrial ecosystems differ in that marine ecosystems are relatively open, while terrestrial ecosystems have more discrete boundaries. As a consequence, migration and dispersal of organisms in various life stages are more characteristic of marine ecosystems. Other dissimilarities originate from
differences in spatial scales of the habitats and contrasts between life strategies in water and on land. Marine ecosystems also may be more variable than terrestrial ecosystems, especially on shorter time scales. Marine ecosystems are subject to the physics of the surrounding medium and respond to forces such as tides, circulation patterns, and decadal shifts in overall productivity, whereas terrestrial ecosystems are more internally controlled by the life processes of the dominant organisms (e.g., trees) and may change only slowly, sometimes on century time scales, unless humans intervene (Steele, 1985, 1991, 1996).
On land, survival of rare or endangered species is especially dependent on habitat, which often plays a decisive role in identifying areas worthy of protection. The case for protection of a terrestrial area to save a species from extinction has provided powerful arguments for garnering public support. Habitat destruction accounts for about 36% of animal extinctions whose cause is known (compared to 23% due to hunting and 39% due to introduced species) and is thought to be even greater for the extinction of terrestrial species where the cause is unknown (Groombridge, 1992). As people increase their use of the land, habitats to support terrestrial species will continue to decline, both from destruction and from fragmentation into areas too small to support indigenous populations.
Human populations appear to have less impact on marine habitats because people do not live in the ocean and thus are less aware of the change. The loss of marine habitat, except for wetlands and estuarine marshes, has been documented infrequently, and population declines or extinctions in marine species are more often attributed to overexploitation. Historically, the concept of conserving critical habitat for endangered marine species has been applied mostly to marine mammals, sea turtles, and sea birds, with only occasional application to endemic fishes or invertebrates (Kelleher and Kenchington, 1992). However, the dramatic loss of coastal wetlands (NRC, 1992) and recent descriptions of the impacts of trawling gear on the seabed (Watling and Norse, 1998), among other stresses, have led to increased attention to the vulnerability of some marine species to extinction from loss of habitat (Roberts and Hawkins, 1999). Even more common is the decrease in genetic diversity from the loss of distinct populations associated with habitat at a discrete site.
In selecting areas for protection, several concepts applied to terrestrial reserves are also important for marine reserves, including sources and sinks, dispersal range, and metapopulations (see Chapter 6). When the range of a species is large and the density of the population is relatively low, it may be impractical to design a reserve that is large enough to protect the species. On land, the solution may require establishing several reserves connected by corridors that allow the physical passage of species. In the ocean, water provides the corridor, and the design issue rests on an understanding of currents and circulation patterns or other oceanographic features that will either facilitate or impede the dispersal of individuals among reserves (see Chapter 6). Also, even sedentary
and nonmigratory marine species commonly have a mechanism for dispersal through a reproductive larval stage that provides a level of insurance against their localized extinctions. As a consequence of these broad dispersal ranges, many marine species do not show genetic isolation even over large distances (Palumbi, 1992; also see Chapter 5).
Although few marine organisms are known to face extinction as a consequence of endemism and threatened habitat, there are important exceptions. The American Fisheries Society (AFS) recently recognized species vulnerable to extinction. These species generally are long-lived, mature slowly, have low fecundity, are closely associated with particular habitats, and are exceptionally vulnerable to fishing or other anthropogenic stresses. High-seas predators (e.g., tunas, marlins, swordfish, sharks), although not closely associated with seabed habitats, also are vulnerable. In a historic move, AFS has adopted policies that acknowledge the special needs of such species, which may become threatened or endangered if not managed wisely. AFS has recommended MPAs as one management tool to protect species at risk of extinction (Musick, 1999: Coleman et al., 2000).
In the marine environment, mobile species such as fish, marine mammals, and sea turtles, move in three dimensions and have a much greater ability to migrate over long distances than is common for organisms in terrestrial ecosystems. This makes it more difficult to identify discrete populations and blurs the apparent boundaries of marine ecosystems. Also, the relative openness and fluidity of marine ecosystem boundaries increase the likelihood that they will be subject to external influences such as pollution from surrounding lands and waters (Steele, 1985, 1991).
Another difference between terrestrial and marine ecosystems is that most seafood is obtained by fishing, not farming. Wild stocks of fish, not aquaculture, remain the major source of the world's seafood (New, 1997; Naylor et al., 1998, 2000), while land-based agriculture, not hunting, is the main terrestrial food source. Therefore, the continued supply of seafood for human consumption is dependent on sustainable fishing practices for the foreseeable future or until mariculture becomes independent of fish-based food sources. Finally, in contrast to the plants and herbivores that dominate terrestrial food production, most exploited fish species are carnivores, and their depletion may have cascading influences on marine food webs, such as the expansion of herbivore populations and subsequent declines in algal coverage from increased grazing pressure.
Differences in Human Perceptions and Use of Marine and Terrestrial Areas
In socioeconomic terms, a fundamental difference between the use and management of resources in the sea and on land arises from historical perceptions or definitions of ownership and the laws and conventions that govern these activities. On land, problems arising from common property rights have been summa-
rized as “the tragedy of the commons” (Hardin, 1968, 1998). The failure of communities to limit use of the commons by individuals in the cause of overall community interest and sustainability has led to a shift in most countries to private or government ownership of most land areas. This shift imbues property owners with a strong incentive to protect the land and its resources from overuse and destructive activities, thus empowering the owners to act as stewards of the land. In contrast, coastal waters have been considered part of the public trust in the United States, a concept applied since colonial times based on English common law, with origins extending as far back as Roman times (Hanna et al., 2000). Internationally, only recently have nations acted to establish ownership of the seabed and overlying waters through declaration of territorial seas and exclusive economic zones (EEZs). These levels of ownership are far more limited than standards applied to most land areas. Nevertheless, since the 1970s there has been a notable shift toward granting privileged access to marine resources for some groups while excluding others. International conventions regarding jurisdiction over marine waters are discussed in Chapter 8.
Outside of EEZs, the concept of ownership of portions of the sea or seabed is slowly increasing, as expressed principally in the United Nations Convention on the Law of the Sea (UNCLOS). Some maritime nations, including the United States, are party to neither UNCLOS nor the Convention on Biological Diversity. Consequently, few areas outside territorial waters are fully regulated with respect to international use. For example, the only marine areas outside national territorial waters in which ship activities are restricted by international agreement are part of the Great Barrier Reef Marine Park and the Sabana-Camaguey Archipelago off the coast of Cuba. These areas were declared to be “particularly sensitive sea areas” by resolutions of the International Maritime Organization (IMO) in 1990 and 1997 respectively, under the provisions of the International Convention for the Prevention of Pollution from Ships (MARPOL).
Implications for MPAs
The general public, as well as special interest groups, cherishes the right to use marine areas and resources without restriction. Historically, attempts by government to limit this freedom, even for the benefit of users, have been fought bitterly by those users. For instance, the National Marine Sanctuary Program has struggled to gain public acceptance of fishing restrictions or prohibitions within areas designated as ecological reserves. In the Florida Keys National Marine Sanctuary, less than 0.5% of the sanctuary is closed to all fishing, and most of the other national marine sanctuaries have no areas closed to fisheries. It is difficult to change the perception that access to marine resources is a right because the open-access doctrine has deep roots in the United States.
GOALS OF MARINE RESERVES AND PROTECTED AREAS
To analyze the usefulness of MPAs and reserves as tools for environmental management, it is important to recognize that this approach has been proposed to meet a wide variety of goals. Typically, MPAs will be established to meet multiple goals, enhancing the efficiency and optimizing the value of the area in the context of coastal and marine area management. These goals are classified into the six categories discussed below.
Conservation of Biodiversity and Habitat
Calls for the preservation of biodiversity and natural habitats stem from many different concerns, ranging from the aesthetic to the economic. A strong component of human nature involves an appreciation of, and a desire to understand, the world around us. People recognize the value of continuity with the past and into the future, and there is a strong desire to perpetuate representative habitats for future generations. A manifestation of this is the fact that many human cultures have established and protected parks, sometimes for thousands of years. This is the heritage value of representative marine habitats and ecosystems. Marine reserves offer an important if not unique means of protecting marine wilderness for the future use of humanity.
Preservation of biodiversity and habitat also has contemporary value because of the ecosystem services provided by natural marine communities. Those communities are threatened by habitat loss and depletion of economically valuable species (Murray and Ferguson, 1998; NRC, 1999a). Examples of marine ecosystem services include goods (e.g., seafood, shells, aquarium fish), life support processes (e.g., carbon sequestration, nutrient recycling), quality of life (beauty, enjoyment of natural seascapes), and potential future uses (drug discovery, genetic diversity) (Daily et al., 2000). Marine reserves function in several ways to conserve biodiversity and habitat, two goals that are inextricably linked.
Protect Depleted, Threatened, Rare, or Endangered Species or Populations
Although documented cases of marine species at risk of extinction are rare, this may reflect the lack of research rather than actual low incidence (Roberts and Hawkins, 1999). Many local marine populations have indeed been severely depleted or are functionally extinct (Dayton et al., 1998), with a potential loss of genetic diversity. For example, giant clams (Tridacna gigas) have been extirpated from several island archipelagoes in the Pacific Ocean by overfishing (Wells, 1997); sawfish (Pristis pectinata) have been eliminated from many estuaries on the east coast of the United States by fishing (Poss, 1998); the white abalone (Haliotis sorenseni) has recently been declared a candidate for the federal endangered species list and may become the first marine invertebrate known to be
fished to extinction (Tegner et al., 1996); and the totoaba (Totoaba macdonaldi), once so abundant in the Gulf of California that millions were landed and their bodies used as fertilizer, now hovers on the brink of global extinction as a consequence of overfishing, loss of estuarine spawning habitat (due to diversion of water from the Colorado River), and bycatch of juveniles in shrimp trawls (Cisneros-Mata et al., 1997). Reserves may be established with the specific goal of protecting such species or preserving habitat considered critical for their survival.
Preserve or Restore the Viability of Representative Habitats and Ecosystems
By preserving representative ecosystems, marine reserves are likely to ensure the conservation of diverse species assemblages and maintain genetic diversity. Although the greater openness of marine systems and the dispersal capabilities of marine organisms help reduce the likelihood of extinction through habitat loss, maintaining the full range of habitat types is necessary for food and shelter to support different stages in the life histories of these organisms and to support ecological processes such as nutrient recycling.
Some habitats are heavily impacted by bottom trawling, pollution, dredging, and oil and gas drilling. Distinctive habitats can be critical to many types of species, for example, as spawning aggregation sites or as juvenile nurseries. These habitats may range from coral reefs to seamounts to mangroves to kelp forests. Losses in biodiversity through habitat destruction generally are unintended (which is not to say unforeseen) consequences of capturing one or more target species using technology that massively impacts habitat and nontarget organisms (Dayton et al., 1995). This point is brought home most forcefully perhaps by considering benthic habitats in which trawling activities have led to massive destruction of physical and biological features and, as a consequence of this destruction, profound alteration of ecosystem structure and function (Thrush et al., 1998). In the case of pelagic fishing, bycatch is likely to be the key negative side effect on nontarget species, but in the case of benthic trawling, the entire ecosystem faces massive disturbance (Watling and Norse, 1998). When essential or significant habitats can be identified, they can be protected by the implementation of reserves. Marine reserves can also be established to help restore disturbed critical habitat.
Fishery reserves can improve fishery management in various ways, depending on the characteristics of the resources, their fisheries, and the management system in place. The following goals of reserves related to fishery management are identified here, with the understanding that such fishing closures are likely to
be embedded in larger management areas subject to different types of fishing and environmental regulations.
Control Exploitation Rates
Reserves can help control or reduce exploitation rates mainly in two ways. First, for species of low adult mobility, reserves can be an effective tool to control catch rates by directly protecting some fraction of the population from the effects of fishing. Indeed, much of the impetus for establishing reserves has come from experience with sedentary reef species, which have been severely overfished in the past, and where fishing pressure has proved difficult to control by other means. In these cases, fishery reserves may help enhance depleted fish stocks, provided the hotspots of reproduction created within the reserves are large and replenish the populations outside reserve boundaries.
A second way in which reserves can reduce fishing rate is by diverting fishing effort away from areas of high fish density areas where fish are less vulnerable. This can be effective in fisheries that are managed by limiting the total amount of fishing effort or in fisheries that are essentially unregulated. The large closed areas now in place on Georges Bank, for example, have been found to contribute significantly to reducing fishing mortalities of cod (Gadus morhua) and yellowtail flounder (Limanda ferruginea), fisheries managed by limiting days at sea. The rebuilding plan for these depleted stocks reduced the catch both by reducing days at sea (i.e., placing tighter effort controls) and by reducing the efficiency of the fishing effort through the implementation of large closed areas on preferred fishing grounds. These closures displaced effort to areas with lower fish densities, thereby lowering the catch per day fished (Murawski et al., 2000). The rebuilding plan for these depleted stocks hence reduced the catch both by reducing days at sea and by reducing the efficiency of the fishing effort. A potential drawback of this approach is that lowering fishing efficiency may spread the impacts of fishing (bycatch and habitat alteration) over a larger area.
When conventional means of regulating fishing such as catch quotas or effort limitations are not an option (because they are either impractical, unenforceable, or too costly, or because the information required is simply not available), large spatial closures placed on areas of high fish concentrations could become the primary regulatory tool. Conventional, single-species management tools, for example, rapidly become impractical in multispecies fisheries when the fleet cannot selectively target individual stocks. Effort cannot be fine-tuned to meet individual species targets. Implementation of catch quotas by species leads to complex arrays of limits on the catch by species per fishing trip, which not only result in high levels of discard but also may fail to reduce fishing mortality. Reserves may be the only practical way to protect the most vulnerable species in these complexes or stocks that have been overfished in the past. Even
if no directed fisheries were allowed on these overfished species, rebuilding may be possible only if areas in which significant incidental catch occurs are closed. This may be the situation for bocaccio (Sebastes paucispinis) on the west coast of the United States; a rockfish for which a rebuilding plan has recently been approved ( www.pcouncil.org/Groundfish).
Protect Critical Stages of the Species' Life History
Protecting nursery grounds, or areas where discards of juvenile fish would be high if they were open to fishing, has been one of the most common reasons for establishing reserves in the past. Closing nursery grounds can be very effective for stock conservation because for most exploited species, a reduction in the mortality of juveniles has a larger payoff in terms of increased mature biomass than a proportional reduction in adult mortality (Horwood et al., 1998). Where the habitat of the nursery grounds is itself vulnerable to damage from fishing, it is clear that reserves will help to protect both the resident juveniles and the ecosystem on which their survival and maturation depend.
Another important goal of reserves has been to protect areas where fish aggregate to spawn. Beyond the possible reduction of fishing efficiency, as discussed above, protecting spawning aggregations may be important (1) for species that exhibit complex reproductive behaviors that would be disrupted by fishing operations; (2) when survival of eggs, larvae or juveniles present on the spawning grounds would be imperiled if fishing were permitted; or (3) when fish aggregate in such high densities to spawn that controlling catches on the aggregations would be difficult (Johannes, 1998; also see Box 2-1).
Reduce Secondary Fishing Impacts
The effects of fishing go well beyond the capture of the target species (Dayton et al., 1995; Watling and Norse, 1998). As noted earlier, the habitat on which targeted species depend may be severely affected by fishing. Depending on the gear used, fisheries may profoundly alter the characteristics of the bottom and benthic ecosystems (Goñi, 1998; Watling and Norse, 1998; Hall, 1999). The protection of benthic habitats from destruction not only will maintain biodiversity, but also may enhance the fishery in question if the target species, at some stage(s) of its life history, depends on critical habitat or components of the ecosystem perturbed by fishing. Many economically valuable species have larval or juvenile stages that depend on particular substrates for settlement or on a complex benthic community for certain types of food and shelter from predation. If habitat destruction imperils pre-harvest life stages, then the fishery is threatened by habitat destruction. Reserves are a primary means to protect such critical habitat, with the potential for enhancing biological productivity.
Gag Grouper Case Study
The gag (Mycteroperca microlepis) grouper population in the Gulf of Mexico has 90% fewer males now than it did 30 years ago. What has happened to cause such a dramatic shift in the sex ratio?
Common fishing practices have disproportionately affected male groupers because of the complex biology and social systems that underlie this fish's reproductive behavior (Coleman et al., 1996). Groupers first mature as females; after receiving the appropriate social cues, some females become males. Aggregations are large groups of fish that form offshore for a relatively short but critical period during the spawning season. If dominant females encounter too few males in the spawning groups, they will change sex in the ensuing year so that more males will be available by the following spawning season. The spawning season and aggregation behavior are confined to a brief period in the late winter or early spring. At other times of year, males and females occur in separate locations, with males remaining offshore while females move to shallower water.
The grouper fishery targets spawning aggregations and the largest fish to obtain the highest yield for the least effort. Because males are larger and attack bait more aggressively, they are caught more frequently. At the same time, the population is less able to compensate for the disproportionate loss of males because fishing disturbs behavioral interactions that promote female-to-male sex change, the natural mechanism for maintaining a favorable sex ratio.
How widespread is the grouper overfishing problem? Declines in the abundance of males have been associated with exploitation in the Gulf of Mexico of both gag (M. microlepis) and scamp (M. phenax)—closely related species with similar life-history characteristics. Declines also have been reported for Atlantic stocks of gag and scamp, as well as other grouper species (e.g., Shapiro, 1979; Nagelkerken, 1981; Bannerot, 1984). In the southeastern United States, 11 of the 19 most important reef fish species are overfished or on the verge of being overfished. Most of them are groupers, and all groupers change sex from female to male. At least two suffer from low proportions of males in the population, and all of them aggregate to spawn. Currently, depleted Nassau grouper (E. striatus) and jewfish (E. itajara) are completely protected from fishing in state and federal waters. Two more species, Warsaw grouper (E. nigritus) and speckled hind (E. drummondhayi), can no longer be commercially fished or sold, and the recreational catch is limited to one fish per vessel per day. Finally, 26 grouper species worldwide are being considered for listing as vulnerable to extinction by the International Union for the Conservation of Nature and Natural Resources.
Current fishing regulations are insufficient to preserve either the social structure or the natural proportion of males among these fishes. Most management approaches fail to address the critical aspects of grouper reproduction. Establishing reserves at spawning aggregation sites could serve four functions:
1. Protect highly vulnerable aggregations from concentrated fishing effort, thus distributing effort over larger areas and longer periods of time.
2. Protect spawning fish so that spawning activity is not disrupted.
3. Prevent disruption of the normal behaviors and social interactions that trigger sex change.
4. Selectively reduce fishing mortality on males.
The concept of designating reserves to protect spawning sites is beginning to influence the management of grouper stocks. In June 2000, the National Marine Fisheries Service approved closure of two areas to fishing (except for highly migratory species) totaling 219 square nautical milesa in the northeastern Gulf of Mexico. These closures will be used for scientific evaluation of marine reserves, both to protect spawning aggregations of gag and other groupers and to evaluate the effectiveness of reserves in maintaining a more balanced sex ratio by protecting male gag from excessive fishing pressure.
a Throughout this report, nmi2 will be used in place of square nautical miles.
Fisheries also impact other nontarget species that are taken as bycatch and often discarded dead at sea. Some fisheries have to be shut down before their quotas can be fished because bycatch limits for nontarget species are reached first. For example, regulations established by the North Pacific Fishery Management Council to reduce bycatch mortality of Pacific halibut (Hippoglossus stenolepis) in Alaska frequently lead to closing the groundfish fisheries for Pacific cod (Gadus macrocephalus), rock sole (Pleuronectes bilineata), and yellowfin sole (P. aspera) when the halibut mortality cap (currently set around 7,000 megatons [mt]) is reached (Adlerstein and Trumble, 1998). Groundfish fisheries suffer because they cannot catch their quotas, and the directed halibut fishery suffers because halibut recruitment is reduced and the biomass of adult halibut killed as bycatch is deducted from the allowable commercial catch. A total annual yield loss of about 11,000 mt was estimated at a time when the halibut directed catch was close to 32,000 mt (Clark and Hare, 1998). Reserves placed in areas where catch rates of nontarget species are persistently high may significantly reduce bycatch rates (i.e., mortality of nontarget species per unit of target species caught) and alleviate some of the problems of multispecies fisheries. Certainly, reserves are not the only means to control bycatch problems; in fact, depending on the situation, gear modifications and other management tools (e.g., individual bycatch caps, mandatory landing of all bycatch species) may prove more effective.
Ensure Against Possible Failures of Conventional Regulatory Systems
Because stock assessment methods can be inaccurate (NRC, 1998a), especially given the limitations of the data normally available for assessments (NRC,
2000c), reserves have been proposed as a way to ensure that harvest rates will not exceed some maximum bound or stock levels will not fall below some minimum threshold. Many managed fisheries in North America are regulated by placing annual limits on the total catch of individual species. Alternatively, the amount and quality of fishing effort are controlled to achieve the desired target harvest rates. However, these methods do not always work, particularly in the absence of reliable estimates of stock biomass (for catch quota systems) or of fishing mortality and its relation to the amount of fishing effort (for effort control systems).
Conserve Life-History Traits and Genetic Diversity
Most fishing methods are strongly size selective, commonly removing the largest and oldest fish at a higher rate (e.g., Parma and Deriso, 1990). This may exert strong directional selection toward slower growth and smaller size at maturity (Ricker, 1981; Thorpe et al., 1983; Policansky, 1993). Sex ratios can also be significantly skewed as a result of fishing when one of the sexes is differentially removed. Sequential hermaphrodites are a classic case; for example, many exploited stocks of groupers change sex from females to males, and the proportion of males in the stock has been critically reduced by fishing (Box 2-1; Coleman et al., 1996). More generally, differential mortality by sex may be due to large sexual size dimorphism or peculiarities in the mating system that result in one sex being more vulnerable than the other. By relaxing the selection pressure from fishing in some segments of the populations, reserves may help conserve the natural genetic diversity for life-history traits (Trexler and Travis, 2000).
Provide a Source of Baseline Data
Marine ecosystems are highly variable associations as a result of both natural variation and anthropogenic effects. Because all factors effecting change in ecosystems operate simultaneously and at different temporal and spatial scales, it is extremely difficult to discern natural from human-induced causes, and this is probably not possible without representative baseline studies and benchmark, undisturbed habitats to use as standards in the evaluation of human-induced impacts. Marine reserves offer the only means of protecting such baseline sites in areas that are otherwise affected by human activities.
Understanding fish population dynamics is hindered by the difficulty of separating fishing effects from natural environmental variability. In species that have low mobility, fishery reserves would provide an unfished control to compare population dynamics inside with dynamics in areas under conventional management. In many cases, stocks managed as separate units might be intercon-
nected through larval and juvenile dispersal and thus would not be dynamically separate replicates. However, even in these situations, protecting some stock subunits from fishing may facilitate research on postdispersal processes (e.g., recruitment and growth) and how they are affected by local density and changes in habitat structure from fishing. Reserves could serve an important role in fisheries research as a tool to study fishing impacts through spatially replicated areas under different management regimes.
MPAs provide a unique opportunity for the public to learn about the diversity of marine life and how human activities both on land and in the sea affect the health of marine environments. Many MPAs, like parks on land, establish interpretive centers and prepare educational material for schools and recreational groups.
Enhancement of Recreational Activities and Tourism
Tourism and recreation could contribute significantly to the commercial value of an MPA. The aesthetic appeal of marine areas for tourism is dependent on the quality of the natural environment—abundant marine life, unpolluted waters, intact habitats. An MPA may serve as a catalyst for the development of a suite of nonconsumptive services that include such diverse elements as shore-based aquaria and museums and seagoing activities such as whale watching. Recreational activities that do not threaten the protection of marine life not only provide local communities with economic opportunities, but also may enhance appreciation and support for the MPA.
Sustainable Environmental Benefits
Marine ecosystems provide benefits beyond harvestable products such as fish and algae. Sometimes referred to as a category of ecosystem services, these benefits include processes such as water purification, protection of coastal areas from storm damage (coral reefs, mangroves, seagrass beds), bioremediation of chemical and oil spills, reduction of atmospheric carbon dioxide through biological carbon sequestration, and nutrient cycling. MPAs and reserves can support the maintenance of marine ecosystems and the services they provide.
Protection of Cultural Heritage
MPAs can also be established to protect areas of distinct character with significant cultural value. Examples of these are protecting archaeological sites, shipwrecks, places of special historical significance, and landscapes or seascapes
to assure the continuation of traditional uses, cultural practices, and sacred sites. These areas fall under Category V of the IUCN system (see Appendix F). The oldest national marine sanctuary in the United States, for example, was designated to protect the site where the Civil War vessel Monitor sank in 1862.
Most MPAs will be established to fulfill several of the goals described above. The purpose of this report is to examine the potential of MPAs, especially areas zoned as marine reserves, for achieving the goals of preserving biodiversity and improving fishery management.