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Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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6

Design

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As with any enterprise, good design is fundamental for the success of marine protected areas (MPAs). This chapter evaluates how existing knowledge of marine ecosystems can be applied to the design of marine reserves and protected areas. Three important questions are covered: (1) How should the location of MPAs be chosen? (2) How large should MPAs be? (3) What kinds of zoning are useful in MPAs?

HOW SHOULD THE LOCATION OF MARINE PROTECTED AREAS AND RESERVES BE CHOSEN?

One of the more controversial issues in designing MPAs is deciding where to put them. While it may be possible to achieve consensus on the need for MPAs and agreement in principle on their size and the entities that should be protected, when it comes to choosing discrete sites, hostilities often break out. Frequently, it is the social aspects of locating reserves within MPAs that dominate arguments. For example, residents of an exclusive development hotly contested plans to include an ecological reserve adjacent to Key Largo in the newly created Florida Keys National Marine Sanctuary (U.S. DOC, 1994). They feared the reserve would prevent them from recreational fishing, or even landing fish, close to their homes. Commercial fishers responded similarly, suggesting that reserves would exclude them from their favored fishing spots. Clearly, social acceptance of the MPA plan, especially the location of reserves, is critical to

Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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TABLE 6-1 Summary of Social and Economic Criteria Used to Select Marine Protected Area and Reserve Locations

Value Type

Criteria

Economic

Number of fishers dependent on the area

Value for tourism

Potential contribution of protection to enhance or maintain economic value

Social

Ease of access

Maintenance of traditional fishing methods

Presence of cultural artifacts or wrecks

Heritage value

Recreational value

Educational value

Aesthetic appeal

Scientific

Amount of previous scientific work

Regularity of survey or monitoring work

Presence of current research project

Educational value

Feasibility or Practicality

Social and political acceptability

Accessibility for education and tourism

Compatibility with existing uses

Ease of management

Enforceability

SOURCE: Adapted from Roberts et al, in review b.

successful implementation (see Chapter 4), but a balance between social concerns and biological function must be achieved. What methods are available for selecting functional reserves that meet these social and ecological criteria?

Kelleher (1999), building on previous work of the International Union for the Conservation of Nature and Natural Resources (IUCN, now the World Conservation Union), provided broad guidelines for selecting MPA sites, drawn from experience in the selection of terrestrial protected areas. He identified several classes of related criteria that bear on choice of a site: biogeographic and ecological criteria; naturalness; economic, social, and scientific importance; international or national significance; practicality or feasibility; and duality or replication. However, these guidelines neither offer guidance on how to prioritize these criteria nor provide advice on how to rank candidate sites according to each criterion.

This approach has been elaborated in recent papers (e.g., Salm and Price, 1995; Nilsson, 1998; Agardy, 1997). A summary of these criteria is provided in Table 6-1. All of these efforts focus on the problem of selecting individual marine reserves, but there is a growing awareness that this piecemeal approach to reserve establishment ultimately may fail to protect species and functional ecosystems. The implication derived from the broad dispersal capabilities and

Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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migratory behavior of many marine species, discussed earlier, is that even the largest reserves may fail to protect all resident species adequately (Ray, 1999). Widely dispersing or migratory species, for instance, will require networks of reserves. Site selection must take into account features at the scale of the reserve, but should also place the reserve into the larger context of the ecosystem within which it is embedded.

Ballantine (1997) proposed a series of principles for the development of regional reserve networks that build on some of the selection criteria for individual reserves. He argued that (1) all biogeographic regions and all habitats should be represented in reserves and (2) there should be replication of reserves within all regions and habitats among reserves. Ballantine also emphasized that within a network, reserves should have some level of connectivity; that is, they should be close enough for resident populations to interact through dispersal or migration. This connectivity among reserves, would be inherent in network design that fulfilled biogeographic, habitat representation, and replication criteria. In other words, fully representative networks with sufficient replication will inevitably contain reserves that are close enough together to interact effectively. Still, Ballantine (1997) offered little guidance as to how to weigh other criteria for selecting reserve sites.

Managers of marine resources would prefer an evaluation process that is more objective. Arbitrary choice of reserve sites could allow vulnerable areas to be degraded or destroyed, while other, more resilient habitats or species are protected. For instance, if criteria are clearly defined and agreed on prior to reserve selection, selected sites can be more easily justified. Much of the opposition that blocked zoning plans for the Florida Keys National Marine Sanctuary hinged on arguments that the locations of zones had not been chosen objectively. One of the original ecological reserve sites proposed, the Dry Tortugas, incorporated an area that satisfied neither conservationists nor fishers. Conservationists argued that it contained too little coral reef, while fishers objected to the extent of shrimp fishing ground that would be lost to them (Ogden, 1997). As a consequence, the siting of the Dry Tortugas reserve was deferred, and a more participatory design process was employed in planning the current site.

The development of more objective approaches could help meet the needs of managers for a more transparent process (Hockey and Branch, 1997; Roberts et al., in review a, b). The COMPARE (Criteria and Objectives for Marine Protected Area Evaluation) procedure described by Hockey and Branch (1997) marries the objectives of reserves to the selection criteria employed. COMPARE specifies 14 different objectives for reserves that are distributed among three categories: fishery management, biodiversity protection, and human use (Table 6-2). The authors propose 17 biological and social criteria that can be used selectively (not all are relevant to all objectives) to determine the value of a candidate site in meeting desired objectives. Sites are scored against each of the criteria, allowing straightforward judgments to be made of their relative value.

Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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TABLE 6-2 Example of the COMPARE Procedure as Applied to Cape Point Nature Reserve in South Africa

Objectives

Criteria

Biogeography

Habitat Diversity

Rare or endemic species

Vulnerable Stages (all species)

Reduced Fishing Mortality

Vulnerable Stages (exploited species)

Adjacent Yield

Spawner Biomass

Research

Monitoring

Ecotourism

Law-Impact Recreation

Education

Exploitation

Totals for Criteria

Percentages

Regionally representative

1

2

1

1

2

7

70

Not conserved elsewhere

1

0

0

0

1

13

High habitat diversity

1

1

1

1

1

5

50

Includes fragile habitats

2

2

1

2

7

88

Houses vulnerable species

1

1

1

1

1

5

50

Protects rare or vulnerable stages

1

1

1

1

1

1

1

4

50

Pristine or restorable

2

2

2

2

2

10

100

Special natural features

0

0

0

1

1

13

Supports exploited species

1

1

1

1

2

2

2

2

12

75

Supplies adjacent areas

1

1

2

50

Large enough

1

1

1

1

0

1

1

1

2

2

1

2

2

1

17

61

Adjacent terrestrial reserve

1

1

1

2

2

2

2

1

2

14

78

Aesthetically appealing

2

2

2

2

8

100

Accessible to people

2

2

2

2

2

2

12

100

Effective management

2

2

2

2

1

2

2

2

2

2

1

2

2

2

26

93

Satisfies social needs

1

2

1

4

67

Preserves historical sites

0

0

1

1

17

Totals for objectives

5

11

6

5

4

8

5

4

19

16

13

10

23

7

136

Percentages

50

79

50

63

50

57

63

50

73

80

54

100

82

88

69

Overall totals

27

21

88

136

Overall percentages

61

55

76

69

SOURCE: Hockey and Branch, 1997.

NOTES: 0 = ineffective; 1 = moderately effective; 2 = highly effective. Blank cells are inapplicable combinations. In this example, the reserve scores 61% for protection of biota, 55% for its contribution to fishery management, and 76% for provision of human uses, or 69% overall. This procedure has been applied to all of the existing reserves in South Africa and has helped evaluate the extent to which they are able to meet their objectives. It has also been valuable in determining what additional MPAs are needed to complete the country's national network.

Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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Page 102

Table 6-2 illustrates an example application of the procedure to an existing marine reserve in South Africa.

The COMPARE approach offers some welcome advantages over ad hoc site selection. It requires that sufficient and comparable data be collected for candidate sites. The simple, semi-quantitative evaluation method neatly summarizes the pros and cons of different sites and helps to pinpoint the deciding factors for making choices. The authors also suggest that management plans for reserves chosen using this approach can be guided by the objectives articulated during selection. It also goes beyond previous schemes in that the process can be used to build regionally representative networks of reserves. It is limited, however, because Hockey and Branch (1997) give only brief guidance on how to score sites according to each criterion.

Another approach that builds upon Hockey and Branch's (1997) efforts includes an evaluation scheme that aims to meld site selection more intimately with network development (Roberts et al., in review a, b). This approach departs from the COMPARE method, however, in that the criteria either are exclusively biological or are dependent on underlying biology. Their rationale is that if social and economic criteria override biological criteria, places of little biological value could be protected at the expense of areas with greater ecological value. The competing needs for biological relevance and social acceptance may be resolved by involving the stakeholder community at the outset in the process of identifying goals for the MPA and reviewing the criteria and data for site selection. Socioeconomic analysis of candidate sites is needed to identify and rule out areas that would be unacceptable to the community and, hence, impossible to implement or enforce.

Biogeographic and habitat representations are at the heart of most schemes for site selection. Leslie et al. (in review) used these criteria to design potential networks of fully protected reserves for the Florida Keys National Marine Sanctuary. They used computer-based selection algorithms to choose network designs that represented all habitats according to their relative coverage in the region. This exercise revealed that there are literally thousands of biologically adequate network designs. Selection from among these designs can be narrowed by identifying those network(s) with the lowest negative impacts on the surrounding communities.

In these examples, as well as other attempts to develop an objective approach to site selection, it is clear that the most subjective issue is the weighting of criteria. This reflects the reality that there is no formula that can be applied across the diversity of situations for planning MPAs. Therefore, involving stake-holders in every step of the process, from providing their knowledge of the environment and its resources, to making decisions about how to score sites relative to each criterion, is the most effective way to develop a cooperative, informed, MPA management plan.

If conservation of biodiversity is the goal, then ecological reserves must be

Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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located in places that will offer protection to the full spectrum of species and habitats. Box 6-1 lists one example of evaluation criteria, and Box 6-2 explains how these criteria could be applied. Biogeographic regions are usually defined on the basis of species composition and, in the marine realm, are often related to hydrographic features. Examples include currents (Emanuel et al., 1992), gradients of water quality (Roberts, 1991), patterns of productivity (Longhurst, 1998), and a complex mix of historical processes. These types of features have been used by Parks Canada for identifying representative marine areas in the development of Canada's National Marine Conservation Areas System. The Parks Canada criteria include

  • geologic features (such as cliffs, beaches, and islands on the coast, and shoals, basins, troughs, and shelves on the seabed);

  • marine features (tides, ice, water masses, currents, salinity, freshwater influences);

  • marine and coastal habitats (wetlands, tidal flats, estuaries, high-current areas, protected areas, inshore and offshore areas, shallow water, and deep water areas);

  • biology (plants, plankton, invertebrates, fish, seabirds, and marine mammals); and

  • archaeological and historic features.1

Within biogeographic regions, candidate sites can be ranked on the basis of species richness or complementarity analyses used to ensure representation of species present (e.g., Roberts et al., in review b; Turpie et al., 2000). However, few sites have detailed data on species composition. In this case, habitats can be used as a convenient proxy for species. Ward et al. (1999) estimate that 93% of taxa will be represented in reserves that cover ≥40% of each habitat type. This is not to say that the presence of species of particular concern should not play a role in site choice. These species can be accounted for in the application of modifying criteria. When habitat representation is the priority, sites that have a high level of habitat diversity will receive a higher ranking.

In setting the goals for an MPA, the following questions should be addressed: Should different habitats be afforded different priority for protection? Are some more or less valuable or vulnerable? Should a greater proportion of some habitats and less of others (i.e., 5% of sandy shores and 30% of coral reefs) be protected? One approach is to protect habitats in proportion to their regional coverage (Ballantine, 1997; Roberts et al., in review a). Thus, if seagrass beds cover 25% of the total region, they would cover roughly 25% of the total area of reserves established. This does not mean that individual reserves would contain


1 http://parkscanada.pch.gc.ca/nmca/nmca/program.htm.
Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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BOX 6-1

Criteria for Selection of Ecological Reserve Sites and Development of Networks
(Roberts et al., in review a)

All of the criteria have a biological basis or strongly affect species and habitats in candidate reserves.

  • Biogeographic representation. All biogeographic regions should be represented and reserves should be replicated in each.

  • Habitat representation and heterogeneity. All habitats should be represented and replicate habitats protected in different reserves within biogeographic regions.

  • Level of human threat. Very high levels of human threat will exclude a site from consideration, but threats that can be mitigated could increase priority for protection.

  • Level of threat from natural catastrophes. Sites that are foci for extreme natural disturbances should be avoided.

  • Size of site. Candidate sites should be large enough to support viable habitats.

  • Connectivity. Sites should interconnect with others through dispersal and migration.

  • Presence of vulnerable habitats. Vulnerable habitats have higher priority for protection.

  • Presence of vulnerable life-history stages. Vulnerable life-history stages, such as spawning sites, are afforded higher priority.

  • Presence of exploitable species. Sites must be capable of supporting exploited species, even though the populations may be at very low levels at the time of implementation due to overfishing.

  • Presence of species or populations of special interest. Endemic, relict, or globally rare species, for example, increase the value of a site, as would populations that are genetically distinct.

  • Ecosystem functioning and/linkages. Areas that link with and support other systems have a greater value than those that do not; similarly, sites that depend on links with other systems are vulnerable unless these places are also protected.

  • Provision of ecological services for people. Services such as coastal protection or water purification add value to a site.


equivalent proportions of each habitat. Some reserves might consist entirely of one habitat, whereas others would contain a variety. Proportional coverage is the simplest argument to make, but there are other possible approaches. The answers depend on the needs of each region, but connectivity among reserves will likely require greater proportional protection of rare than of common habitats (Roberts et al., in review a).

In some cases, the primary objective for establishing an MPA may be to reduce or exclude pollution or mining. One of the main purposes of designating

Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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the Great Barrier Reef Marine Park in Australia was to exclude oil drilling and coral mining (Kelleher and Kenchington, 1982). Similarly, a primary motivation for establishing some of the National Marine Sanctuaries, such as the sanctuary in Monterey Bay, was the exclusion of oil and gas exploitation.

Potential sites may be scored against a series of six modifying criteria that affect their value as candidates for MPAs and reserves. Not all of these criteria are applicable to all objectives for MPA sites, but each is important for the development of successful networks of marine reserves:

    1. Supplement or supplant conventional management of exploited species.

    2. Protect rare species or vulnerable habitats. Vulnerable habitats generally include a biological component that is sensitive to disturbance and may take many years to regenerate.

    3. Safeguard critical life-history stages, for example, spawning aggregation sites or juvenile nursery grounds (see Chapter 5).

    4. Secure linkages among interdependent habitats. For example, communities present on rocky shores may derive their sustenance from adjacent kelp forests (Bustamante et al., 1995), and mangroves may protect offshore reefs from sediment carried by terrestrial runoff (Duke et al., 1997).

    5. Maintain an ecosystem service such as the water filtration function performed by suspension-feeding invertebrates in bays and estuaries.

    6. Provide connectivity among reserves for persistence of species or between reserves and unprotected areas for repopulation of exploited populations.

The application of these criteria depends on the goals of the MPA and zones designated as reserves. For example, the design of MPAs to improve fishery management may emphasize criteria 1, 3, and 6. Designing MPAs for conservation of biodiversity may emphasize criteria 2, 4, and 6.

It is logistically difficult to conduct experiments to evaluate connectivity. Roberts (1997a) suggested using prevailing current patterns to map connections among areas. However, others point out that currents may not reveal the true linkages if species actively control their pelagic dispersal (Swearer et al., 1999; Warner et al., 2000; Barber et al., in press). Biogeographic patterns of distribution provide a boundary within which connectivity may be evaluated. These boundaries may not depend on current patterns. For example, Barber et al. (in press) found that present-day current patterns could not explain patterns of genetic similarity among populations of mantis shrimps on Indonesian coral reefs. Generally, connectivity will be achieved automatically when networks of reserves are designed according to the other criteria, as found when these criteria were used to propose sites for marine reserves in Europe (Halfpenny and Roberts, in review). However, any obvious gaps should be avoided.

The schemes developed by Hockey and Branch (1997) and Roberts et al. (in review b), although applicable to the problems of reserve selection and network-

Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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BOX 6-2

Decision Process for Developing Reserve Networks
(Roberts et al., in review b)

    1. Define the goals of the network.

    2. Define area of interest.

    3. Divide it into possible reserve units—these may be defined in many ways, for example through grids of uniform-sized blocks (e.g., 10 km2), stretches of coastline, habitat classification schemes, or other means.

    4. Select criteria for the evaluation of units that are appropriate to the goals.

    5. Decide how to quantify the information needed to determine the level achieved for each criterion.

    6. Assemble information on these units (e.g., species or habitats present, levels of threat).

    7. Evaluation process:

    a. Characterize or score sites based on the following characteristics:

    Define biogeographic regions and then score sites based on what region they occur in. At this stage, sites could be stratified according to region and site selection decisions made separately for each region. The latter approach would be most useful where a large geographic area is being considered and there are many potential sites from which to choose.

    Define habitats within each biogeographic region for representation.

    Exclude sites that are subject to excessive levels of threat from human or natural sources.

    Include sites that are already reserves.

    Score potential reserves on the basis of habitat heterogeneity and representation criteria, ensuring that reserve units will be sufficiently large to include viable populations.

    Rank or score sites within each habitat type according to other modifying criteria.

    b. Set conservation targets for each of the criteria above (e.g., decide what proportion of the region and of each habitat to protect, what level of replication is required, levels of connectivity desired).

    c. Select among sites for inclusion in the network (this can be done with an algorithm or by a ranking or scoring method). Criteria may be given different weights at this stage in order to meet specific network objectives. Map the different biologically adequate networks of reserves that are possible.

    d. Ensure that alternative reserve networks resulting from the above selection process are sufficiently connected.

    8. Use information on alternative, biologically adequate, reserve networks to inform final network selection according to socioeconomic criteria.


ing, may also be used to choose boundaries of individual MPAs or to designate zones for reserves within MPAs. Lafferty et al. (in review) show how these criteria can be applied to the problem of placing no-take zones in the Channel Islands National Marine Sanctuary in California.

Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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The Importance of Developing Multifunctional MPAs and Reserve Networks

The fragmentation of objectives among different management entities often leads to a proliferation of uncoordinated zoning measures. McArdle's (1997) review of the 104 California MPAs, for instance, shows how the uncoordinated designation of sites results from overlapping, competing, and sometimes conflicting agendas of the different management agencies. This leads to a morass of legislation that perplexes users and may in the end harm, rather than help, conservation by giving the illusion of protection where little exists. For example, only 4 small MPAs, of the 104 in California, prohibit all recreational and commercial fishing.

Agencies need to cooperate in the establishment of MPA networks in order to reduce the costs of planning, implementation, and enforcement. Furthermore, implementation of a coordinated network of MPAs, using a selection scheme such as the ones described here, will ensure the greatest conservation benefit per unit area protected. The executive order issued by President Clinton on May 26, 2000, recognizes this need and directs the National Oceanic and Atmospheric Administration (NOAA), in cooperation with the Department of the Interior, “to establish a Marine Protected Area Center...to develop a framework for a national system of MPAs.”

Biodiversity conservation, fishery production, and the full suite of ecosystem services depend on maintaining ecosystem integrity. This is a central objective for the creation of representative systems and fully interconnected networks (Agardy, 1997; Roberts et al., in review a, b). Fragmented initiatives are much less likely to safeguard ecosystem processes.

If reserves are to enhance fisheries through spillover of juveniles and adults, they must have “leaky” edges. As already discussed, larger reserves will have lower relative rates of export across their boundaries than small ones because the edges form smaller proportions of the area. For species that associate closely with particular habitats, reserve boundaries will be more porous (and spillover greater) if they are placed across areas of continuous habitat (Roberts, in press). Reserves whose boundaries are contiguous with habitat discontinuities will tend to have lower rates of spillover. However, reserves in which export rates are too high will fail on both fishery and conservation grounds. A balance between retention and spillover can be achieved at the reserve and network scales by incorporating a mix of boundary conditions.

As described in Chapter 5, sources are locations that supply recruits to other places, whereas sinks are places supported by recruitment from elsewhere without contributing to other areas (Pulliam, 1988). Crowder et al. (2000) modeled a system of sources and sinks for reef fish and found that at high fishing effort, placement of reserves in sink areas not only reduced the capacity of the reserve to support the fished population, but also concentrated fishing on source popula-

Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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FIGURE 6-1 Three possible trajectories for community recovery (e.g., of biomass, abundance, or diversity) within marine reserves following protection from fishing at time 0: (a) high-quality habitat within reserve, (b) moderate-quality habitat, and (c) low-quality habitat within reserve. The rate and extent of recovery increase as habitat quality increases. Reproduced from Roberts, 2000.


tions. The model suggests that displacement of fishing effort to source populations could actually further the decline of a fish stock. Therefore, when reserves are established to benefit particular fish stocks the relative productivity of different areas should be considered. The higher the quality of the habitat, the greater are the expected extent and rate of recovery (Figure 6-1). It will not be possible to document source and sink sites for each individual species, particularly when a reserve is established for the full spectrum of biodiversity. For some species, source and sink areas may shift with fluctuating environmental conditions. A site that is a source for one species may be a sink for another, and a site that is a sink today may become a source in a few years. Establishment of a network of reserves can help address this complexity by covering a range of habitat types distributed throughout a region.

How Do International Political Boundaries Influence Reserve Selection?

Thus far, network development has been framed in the context of biogeographic regions, but biogeographic boundaries rarely coincide with political ones. How will this affect network development? If all countries were to commit to

Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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establishing comprehensive, representative networks of reserves, those networks should naturally link up across political borders. However, there are good arguments for greater collaboration among countries in planning reserves. For some countries, especially those with short coastlines, local initiatives may fail to produce the desired benefits unless similar initiatives are implemented by adjoining countries with which there are strong resource linkages.

In politically diverse regions, such as the Caribbean, the number of possible partner nations with which countries have to coordinate marine resource management seems daunting. However, maps of current patterns in the Caribbean reveal approximate upper bounds to dispersal distances for pelagic larvae with different larval durations (Roberts, 1997a). Potential dispersal routes and distances can be used to identify upstream and downstream partner countries. For example, recruitment on coral reefs in Florida probably includes inputs of larvae from reefs off Cuba and several Central American countries; therefore the quality of resource management in these countries should concern managers in Florida (Ogden, 1997).

Cross-border reserves illustrate a second way in which international collaboration can be beneficial. Border areas are frequently regions of political tension, with conflicts arising over vessels from one nation fishing in the waters of another. Fully protected reserves that straddle borders could help reduce conflict and, at the same time, improve the condition of marine resources in both countries. Such reserves have been proposed for the Hague Line, which defines the border between eastern Canada and U.S. waters in the Gulf of Maine (McGarvey and Willison, 1995; http://www.atlantisforce.org, June 2000), and for the waters separating the U.S. Virgin Islands and the British Virgin Islands. There is already a trinational reserve project under way in the Caribbean, encompassing the waters of Belize, Guatemala, and Honduras (Heyman and Kjerfve, 1999). This project is underpinned by knowledge of current patterns that link the resources of all three partners. Networks of MPAs and reserves that are designed to provide regional benefits across national boundaries can distribute the opportunity costs of establishing protected areas among coastal communities and countries.

Such international reserves could also help resolve territorial disputes. McManus and Meñez (1997) have highlighted the potential for an international reserve in the Spratly Islands of the South China Sea. Coral reefs of these islands are among the least impacted in Southeast Asia, and they may be a source of larvae for reefs in countries bordering the region.

Can Reserves Contribute to Conservation and Management of the Open Ocean?

The overwhelming majority of reserves established to date have been in coastal areas, extending at most to the limit of the continental shelf where the impact from human activities is most obvious. These places are intensively used

Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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by people and receive the most direct input of pollutants from land. However, open ocean areas are also impacted by human activities, raising the question of whether reserves should be established in the high seas.

Human impacts on the deep sea are increasing, with dumping, fishing, and mining the three most significant threats to deepwater habitats. Deep-sea fish species (fish occurring at depths of 200 to 2,000 m) have increasingly become the target of commercial fisheries, as trawling effort has shifted from continental shelves to deep slopes and seamounts (McAllister et al., 1999). Fishers regularly trawl at depths up to 2 km, with about 40% of the world's trawling grounds now located in deep water. Trawling for orange roughy (Hoplostethus atlanticus) off Australia and New Zealand has stripped seamounts of their unique invertebrate fauna (Dayton et al., 1995). Recent research has found high levels of endemism on these seamounts, raising the possibility that undescribed species are becoming extinct as a consequence of damage from trawling (de Forges et al., 2000). Reserves could provide these deep-sea communities much needed protection from collateral damage due to fishing as well as damage from mining or dumping. It is notable that the collapse of fisheries in shallower waters has often stimulated governments to promote deepwater fisheries (Haedrich, 1995; Moore, 1999).

Discovered less than 25 years ago, hydrothermal vent ecosystems have become an important topic of study in marine science and now are emerging as a focus for conservation as well. The fauna at the vent ecosystems occurs nowhere else in the deep sea, and a high level of endemism appears to exist at many vent sites. The geological and geochemical characteristics of the hydro-thermal vents are also unique, and the polymetallic sulfide deposits formed at spreading centers are a potential source of economically valuable minerals such as copper ores.

Creation of marine reserves at deep-sea hydrothermal vent sites has been proposed for two quite distinct reasons (see http://triton.ori.u-tokyo.ac.jp/~intridge/reserve.htm). First, in view of proposals to mine the mineral wealth found at hydrothermal vent sites, reserves have been proposed as a means of protecting some fraction of these unique ecosystems from destruction. Biodiversity concerns loom large in view of the endemism associated with the vents. Second, as research programs have developed, conflicts have arisen between “observational” studies to provide long-term data on the development of vent ecosystems and “manipulative” studies to collect biological or geological specimens. Observational studies require closure of some areas within the vent ecosystem for ecological reserves that may be monitored, but not altered, by human activities.

Scientists working at vent sites are encouraged to communicate their needs through a Web site (http://triton.ori.u-tokyo.ac.jp/~intridge/reserve.htm) established by the InterRidge program, an international consortium of vent scientists. This Web site provides a single source of information on proposed vent studies, enabling scientists to anticipate and resolve potential conflicts between research

Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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programs. Formal establishment of reserves at hydrothermal vent sites by government agencies has commenced. In 1998, the Canadian government established the first pilot MPA at a hydrothermal vent site in the northeastern Pacific, the Endeavor Hot Vents Area, which is part of the Juan de Fuca Ridge System (see http://www.oceansconservation.com/mpa/related/fsendeav.htm).

The open ocean, like deep-sea regions, has seldom been considered as a potential location for reserves. Fisheries of the open ocean are heavily exploited, currently for migratory species such as tuna and swordfish, but formerly for whales. Over time, the scale and efficiency of exploitation have increased relentlessly, leading to significant declines and overfishing in many of these fisheries (Safina, 1998b). Impacts of exploitation also extend far beyond target species (Dayton et al., 1995). Tens of thousands of marine mammals and birds are caught annually as bycatch in drift nets, and thousands of turtles and birds are killed by longlines. Swordfish fisheries kill several sharks for every swordfish landed. There is an urgent need to protect species of the open ocean, and MPAs may be an important tool to achieve this objective.

A problem that complicates efforts to manage deep- and high-seas fisheries is that many operate in international waters. Nations are less inclined to regulate activities on the high seas than in nearshore waters because they lack jurisdiction over such regions. However, there appear to be many circumstances under which MPAs might provide benefits in these regions. There are some precedents, including the Indian Ocean Whale Sanctuary, the Antarctic Treaty, and the Torres Strait Treaty between Australia and Papua New Guinea. Enforcing offshore MPAs will be a challenge, but the development of satellite tracking technology for fishing vessels (vessel monitoring systems) and other technologies may solve these problems.

HOW LARGE SHOULD MARINE PROTECTED AREAS BE?

The question of size has two elements: (1) How much of the sea should be protected in total? (2) How large should individual reserves be?

How Much of the Sea Should Be Protected?

The question of how much of the sea should be protected from human disturbance is one of the most vexing issues surrounding marine reserves. In the terrestrial realm, the World Conservation Union (IUCN) has recommended that 10% of each country's land area be set aside in protected areas. However, many think that the more open character of marine ecosystems requires that higher targets be set, with 20% most often cited as the appropriate range (Schmidt, 1997). The U.S. Coral Reef Task Force (USCRTF, 2000) has recommended that 20% of coral reefs and associated habitat types receive protection in reserves. Although the 20% figure is widely quoted, it is often criticized as being arbitrary

Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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and unscientific. To many fishers, it seems unnecessarily high. When the Reef Fishery Plan Development Team (RFPDT, 1990) recommended the protection of 20% of the continental shelf off the southeastern United States in 1990, its report was met with incredulity and hostility from the fishing industry, and the proposal was shelved.

This section provides an overview and synthesis of studies examining the question of how much area in the sea should be protected. Table 6-3 summarizes 35 studies that approach this question from a range of perspectives, and a description of each study is provided in Appendix G. The table is organized according to the principal issues addressed in each study: (1) ethics, (2) risk reduction, (3) yield maximization, (4) preservation of biodiversity, and (5) increasing connectivity among reserves. Many of the more influential studies are discussed in detail in the text.

The goal of protecting 20% of the sea was first proposed by the Reef Fishery Plan Development Team (RFPDT, 1990). The rationale come from a fishery model indicating that recruitment overfishing could be avoided by maintaining stocks at or above 20% of their unfished biomass (Goodyear, 1993) and from experience with habitat closures for several invertebrate species in the southeastern United States (Bohnsack, 1996). Later analyses suggested that some stocks should be kept above 35% or even 40% of their unexploited biomass (Mace and Sissenwine, 1993; Mace, 1994), but the 20% figure for reserves persists. Others have suggested that even higher targets are necessary, such as maintaining 60% or even 75% of unexploited biomass if reserves are used as the primary management approach (Hannesson, 1998; Lauck et al., 1998; Mangel, 2000).

A common argument for using reserves in fishery management is to provide insurance to counter the uncertainty inherent in conventional management (Chapter 3 and Chapter 5). Lauck et al. (1998) showed that irreducible uncertainties in estimates of population size and fishing mortality make it difficult for managers to avoid driving stocks below critical target levels. Large closures provide a riskaverse strategy for meeting management objectives. Models suggest that reserves covering between 30% and 60% of management areas would offer risk reduction (Table 6-3).

Several common conclusions can be drawn from a broad range of biological and economic models that address the role of reserves in improving fishery yields. First, reserves are likely to support increased yields for overexploited fisheries, but considerable areas must be protected to achieve such benefits. Second, as fishing pressure outside reserves increases, the size of the area in reserves must also increase to sustain the population. Third, without other management measures, highly mobile and migratory species will require very large (70-80%) closures. However, most proposals for establishing reserves for migratory species focus on protecting vulnerable life stages, such as spawning grounds or juvenile habitat, whereas most models simply address lowering fishing mortality (see Chapter 5).

Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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TABLE 6-3 Summary of Studies Estimating Marine Reserve Area Relative to the Conservation or Management Objective

Goal

Citation

Criteria (Species)

Area

Ethics

Ballantine, 1997

Typical terrestrial target

10%

Risk

Risk management

Lauck et al., 1998

Roughgarden, 1998

Guénette et al., 2000

Mangel, 2000

Recruitment overfishing

Goodyear, 1993

Mace, 1994

Mace and Sissenwine, 1993

Sumaila, 1998

DeMartini, 1993

Uncertainty in stock assessment

Spatial model, with and without additional regulations (cod)

Maintain stock at target levels

Prevent recruitment overfishing

Precautionary approach

Prevent recruitment overfishing

Bioeconomic model, cost-benefit (cod)

Yield-per-recruit model, adult mobility (coral reef fish)

31-70%

75%

20%

20-30%

+20%

+40%

+35%

30-50%

20-50%

Risk minimization and bycatch avoidance

Man et al., 1995

Metapopulation model

20-40%

Risk minimization and yield maximization

Soh et al., 1998

Foran and Fujita, 1999

Guénette and Pitcher, 1999

Target high biomass areas (rockfish)

Fecundity and recruitment (Pacific ocean perch)

Fecundity and recruitment (cod)

4-16%

25%

+30%

Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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Yield Maximization

Pezzey et al., in press

Sladek Nowlis and Roberts, 1997, 1999

Sladek Nowlis, 2000

Sladek Nowlis and Yoklavich, 1998

Holland and Brazee, 1996

Hannesson, 1999

Polacheck, 1990

Hastings and Botsford, 1999

Botsford et al., 1999

Attwood and Bennett, 1995

Quinn et al., 1993

Daan, 1993

Bioeconomic model (coral reef fish)

Fishing intensity (reef fish)

Fishing intensity (Caribbean white grunt)

Catch enhancement (Pacific rockfish)

Bioeconomic model (red snapper)

Bioeconomic model (cod)

Yield per recruit model/adult dispersal (cod)

Reproductive output (sea urchin)

Vulnerability to recruitment overfishing (sea urchin)

Increase spawning stocks (recreational surf zone fishing)

Allee effects and dispersal (sea urchin)

Reduce fishing mortality by 10-14% (cod)

21-40%

40%

30%

20-27%

15-29%

50-80%

10-40%

35%

8-33%

33%

50%

25%

Biodiversity

Representation

Turpie et al., in press

Bustamante et al., 1999

Ward et al., 1999

Species representation, complementarity (fish)

Representative habitats

Habitat and species assemblages

10-36%

36%

40%

Maintenance of genetic variation

Halfpenny and Roberts, in review

Trexler and Travis, 2000

Habitat representation or replication

Selective pressure from fishing

10%

20%

Increase Connectivity Among

Reserves Roberts, in review a

Dispersal distance

30%

Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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Image: jpg
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FIGURE 6-2 Hypothetical population densities of a marine invertebrate species along an imaginary stretch of coastline with two fully protected reserves. Due to Allee effects at reproduction, the species can reproduce successfully only above a certain threshold of population density, shown as the checked area on the figure. In this circumstance, such densities are reached only inside reserves. Although the species exists outside reserves, only the reserve populations contribute to recruitment.


Although fishery management issues provide much of the justification for reserves, some recent studies have examined more general conservation arguments. Almost all discussions of the design of systems of reserves emphasize the importance of preserving the same species and habitats through replication in several different reserve sites. Several studies that have evaluated how much area needs to be protected to achieve representation and replication conclude that areas in the range of 10% to 35% are appropriate (Table 6-3). Broad species conservation may also require interconnected reserve networks. Interreserve distance provides a measure of connectivity (or the likelihood of interaction among populations in different reserves). Species that depend on other populations for recruitment will require networks of reserves that have high connectivity. Connectivity is also critical for persistence of species that are functionally extinct in areas outside reserves, for instance, when an Allee effect demands high population density for reproductive success (Figure 6-2). To extending this argument; if management outside the reserve is poor, the level of human impact

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will be greater, and larger protected areas will be needed. Most fishery models and a metapopulation model (Man et al., 1995) show that larger closures are needed to maintain populations if no additional management measures are applied outside the reserves. Beyond predicting that more reserve area will be needed as human impacts increase, we still have no clear guidance as to how the proportion of sea requiring protection will change as the intensity of impact outside reserves increases. It is probable that different habitats will require different levels of protection.

To represent and replicate habitats adequately in a reserve system designed for conserving biodiversity, reserves covering more than 10% of the seas are likely to be required. However, providing insurance against overfishing and protecting nursery areas, spawning aggregation sites, or migration bottlenecks may require reserves covering a larger fraction of a given region.

This review underscores the arbitrary nature of the 20% target figure. Few studies to date have assumed any protection outside reserves. Modeling studies suggest that less area would have to be protected as management outside reserves improves. Even with excellent management of nonreserve areas, a reserve system covering around 10% of the area would improve the conservation of ecological communities, provide insurance against uncertainty, and allow monitoring of natural versus human impacts. With less effective management outside reserves, 20% or more may be needed to achieve conservation goals. In any case, the particular characteristics of the habitat, the exploited species, and the management regime will affect how much area is needed to meet management goals. Optimally, areas targeted for full protection (i.e., ecological reserves) will reside within MPAs to provide a buffer zone that enhances the conservation benefits of the reserve. These MPAs could cover a much larger proportion of the region—for example, the Florida Keys National Marine Sanctuary (FKNMS)—while affording full protection only within specified zones.

How Large Should Individual Reserves Be?

To date, much of the evidence on reserve effects has come from small and isolated reserves that are closed to fishing (consisting primarily of artisanal fishers) in the Philippines (Alcala, 1988; Russ and Alcala, 1996) and even a tiny reserve encompassing only 2.6 hectares of coral reef in St. Lucia (Roberts and Hawkins, 1997). The increases observed in species abundance and biomass indicate, first, that fishing has a measurable impact on marine ecosystems and, second that reserves can be used to facilitate recovery of depleted fish stocks. Although in St. Lucia, even some mobile species benefited from the reserve, species that range widely are likely to gain less from small than from large reserves.

Halpern (in review) analyzed data from studies of 76 reserves that were closed to at least some forms of fishing and looked at the magnitude of effects in

Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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relation to reserve size. He found that overall effects (combined across all taxa in each study) on abundance, biomass, body size, or species richness were similar in large and small reserves. Although these findings provide support for using small reserves as a management tool, small reserves will not necessarily meet all management needs. Modeling studies predict that protection of mobile species will increase with increasing reserve size. Also, most of the studies in this review did not evaluate the contribution of the reserves to the populations in the surrounding areas. Since many reserves are established to enhance fishery yields, this is an important criterion for evaluating the effect of size on reserve function.

The size of an individual reserve must be balanced against the mobility of the primary species requiring protection and the need for conservation versus enhancement of the fishery. Relative exchange rates will decrease as the size of the reserve increases (Kramer and Chapman, 1999), and for this reason, conservation goals will be better served by large reserves. However, if fisheries are to benefit from spillover of adults and juveniles, there must be net emigration out of reserves. Therefore, fisheries for species with low to moderate dispersal potential will be better served by smaller reserves spaced out across a management area. To meet multiple conservation objectives, networks must incorporate reserves of a variety of sizes.

To be successful, reserves should be large enough to support the persistence (continued existence) of the species within. Modeling results for reserves of different sizes and species with different dispersal characteristics indicate that persistence is generally ensured if reserve breadth exceeds the dispersal distance of resident species by 1.5 times (Hastings and Botsford, 1999). Hence, a larger reserve is more likely to support the persistence of a greater number of species.

The persistence of long-distance dispersers in reserves may depend on recruitment from elsewhere, either from other reserves or from unprotected areas. The availability of recruits will increase with the size of the regional population. Therefore, recruitment will depend on the regional distribution of suitable habitat, the level of exploitation outside reserves, and the amount of habitat within the reserves (Roberts, in press). Consequently, smaller reserves may be effective when the exploitation of species outside the reserves is well managed or when the proportion of protected area increases (Roberts et al., in review a). Beyond these general predictions, there are no hard-and-fast rules about how large a reserve must be for persistence.

The viability of marine reserves depends on more than biology. It requires adequate enforcement and compliance—greater acceptance of small areas generally translates into higher compliance. If levels of compliance and enforcement decrease as reserves become larger, the effects of increasing size on ecological recovery may be obscured. Hence, the conclusion that size does not influence the magnitude of response (e.g., Halpern, in review) in the protected populations could be misleading.

Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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The relationship between the acceptance and ease of enforcement of reserves will depend on the location. Ballantine (1997) notes that acceptability is lower when current use of potential protected areas is intense. He suggests that reserves should be smaller when they are close to coasts than when they are farther offshore. Furthermore, although small reserves may be easier to enforce where it is easy to identify their boundaries and there are many people to watch them, they will be almost impossible to enforce where boundaries are hard to distinguish and patrols are intermittent. Thus, small reserves will be enforceable near coasts but not farther offshore, whereas large reserves will be less acceptable nearshore but may an be implemented and enforced offshore.

MULTIPLE-USE ZONING OF MARINE PROTECTED AREAS

The primary focus of the first section of this chapter has been fully protected reserves, but the intensity and extent of our activities in the ocean are likely to require broader management approaches that offer different levels of protection. For example, as currently conceived, the National Marine Sanctuary Program has a mandate to ensure harmonious use of resources within its sanctuaries. Under this mandate, it is unlikely to be either feasible or desirable for all of the area within sanctuaries to be fully protected. Nevertheless, larger-scale MPAs, such as the FKNMS, play a critical role in coordinating management. To accommodate the spectrum of different uses in larger MPAs, zoning plans are required. Zoning plans will be needed for all but the smallest MPAs because they avoid unnecessary restrictions and facilitate cooperation between managers and users.

The principal objectives of a zoning plan are usually (Kelleher and Kenchington, 1992)

  • to ensure the conservation of the MPA in perpetuity;

  • to provide protection for critical or representative habitats, ecosystems, and ecological processes;

  • to separate conflicting human activities;

  • to protect the natural and/or cultural qualities of the MPA while allowing a spectrum of reasonable human uses;

  • to reserve suitable areas for particular human uses, while minimizing the effects of these uses on the MPA; and

  • to preserve some areas of the MPA in their natural state undisturbed by humans except for the purposes of scientific research or education.

What Types of Zoning Are Useful in MPAs?

Fully protected reserves within larger MPAs help underpin their biological function and ensure that resources are adequately protected. They are especially

Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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useful in giving a high level of protection to core areas, such as sensitive habitats or sites important to vulnerable species. For the reasons given earlier, fully protected ecological reserves should often be permanent features of MPAs. Their conservation and fishery benefits will be greatly diminished if protection is only temporary. Although the placement may have to be adjusted, in concept, ecological reserves should be established with the expectation of permanence. In addition to these fully-protected reserves, zoning plans can be used to separate incompatible activities and provide spatially defined management areas that help protect ecosystem attributes while allowing compatible uses.

The focus of marine management in the United States has historically been on commercial and recreational fishing. The interests of fishers have dominated discussions of how to manage the sea; hence, zoning issues often center on fishery regulations. Certainly, conventional fishery management tools, such as seasonal closures or bans on the use of certain kinds of fishing gear, offer useful tools for zoning. The scope of zoning decisions is becoming broader as other groups have demanded representation of their interest in experiencing pristine marine environments. Among them, the most active are conservation groups, but others are growing in voice and include scuba diving groups, animal rights groups, and scientists. Ecological reserves will secure some objectives of these groups but cannot satisfy all conservation goals. Hence, zones could be created that allow catch-and-release fishing, or that are protected from disturbance by particular types of fishing gear. Zoning to manage compatible and incompatible uses within a large MPA allows for resolution of conflicts between conservation goals and marine resource users, and represents an important tool for meeting the broader goals of coastal zone management (Figure 6-3).

Zoning can be useful as an experimental tool, especially as a component of adaptive management. It can be difficult to determine the relative effects of fishing, environmental degradation, and other human perturbations without large-scale, long-term empirical studies in areas where the suspect activity or most activities have been curtailed. User groups often argue that their activities are not harmful and should not be restricted within MPAs. Recreational users argue that catch-and-release fisheries and diving-related tourism are nonconsumptive and should be allowed to continue in a fully protected area. Yet damage to ecosystems may occur from such activities, and opposition may arise if some users believe that the MPA is being designed to reallocate rather than conserve resources. For example, commercial fishers may argue that their access is being restricted to benefit the recreational fishing industry. By utilizing different sets of restrictions for different areas, experimental zoning schemes can help determine the impacts of different activities and avoid potential conflicts over allocation.

Fishers in Australia and off southeast Alaska have argued for a vertical (i.e., depth-specific) zoning scheme in reserves designated to protect features such as seamounts and pinnacles. For instance, an area closed to bottom trawling might

Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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Image: jpg
~ enlarge ~

FIGURE 6-3 Schematic diagram indicating how different levels of protection can be applied to zones within a large MPA or used to designate a smaller area (also considered an MPA) to achieve a specific goal. Definitions of MPA, ecological reserve, and fishery reserve are presented in Chapter 1.


NOTE: EEZ = exclusive economic zone.

still allow commercial surface gear such as hook-and-line operations or trolling gear to be used. The Australian seamounts, rising 1,000 to 2,000 m above the seabed, harbor distinct species assemblages found nowhere else in the world. Similarly, two unusually diverse pinnacles off Cape Edgecumbe in southeast Alaska, rising 100 m off the seabed, provide refuge for social aggregations of juvenile rockfish and nesting male lingcod. In each case, the proposed closure prohibits bottom fishing and boat anchoring, thus providing refuges for groundfish and preventing damage to habitat, but allowing surface or mid-water fisheries to continue. Fishers argue that the overlying assemblages are not directly associated with the seamounts or pinnacles and could still support viable recreational and commercial fisheries. Thus, they argue for vertical zoning to allow midslope pelagic fishing. However, it will be important to determine if there are linkages between benthic and pelagic species to ensure that exploitation of surface or midwater fisheries does not harm benthic communities and undermine protection of the reserve.

Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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Part of the problem in vertical zoning is enforcement—it is more difficult to monitor vessels for compliance in a reserve that allows a pelagic fishery than to monitor when fishing vessels are excluded. In the Oculina reserve off Florida, there is evidence that some fishers use modified trolling gear to fish illegally on the bottom (C. Koenig, Florida State University, personal communication, 1999). In such cases, a total closure would be easier to enforce.

Zoning Plans

Zoning plans should consider local use patterns, expectations, attitudes, and knowledge of users with planning undertaken by people closely acquainted with local conditions. Thus, it is not reasonable to expect development of a “one-size-fits-all” model. The format of a zoning plan will vary depending on its legislative basis and local conditions. It may range from a small-scale, locally adopted, municipal plan such as those developed in the Philippines by Alcala and White (1984), to a nationally endorsed legal instrument as required under Australia's Great Barrier Reef Marine Park Act. Whatever the format, most plans will include the following elements:

  • statement of the goals and objectives for the planned area as a whole;

  • definition of the area with a formal statement of the boundaries of the planned area, a geographic description of its setting and accessibility, and a description of the resources of the area;

  • description of activities in the area, concentrating on present uses but in the context of past types and levels of use in the absence of a plan—the description should include social and economic analyses;

  • description of the existing legal and management framework applying to coastal fisheries, marine transportation, and other present uses of the area; where they still exist or can be recalled, traditional practices of management, ownership, or rights to the use of marine resources should be described;

  • analysis of constraints and opportunities for activities possible within the area;

  • statement of the principal threats to the conservation and management of the area;

  • statement of policies, plans, actions, interagency agreements, and responsibilities of individual agencies existing or necessary for conservation and management of the area that is to meet the objectives of the MPA and to deal with threats and conflicts—this may usefully include a summary of consultative processes followed in plan development;

  • statement of the boundaries, objectives, and conditions of use and entry for the component zones of the planned area;

  • provision for regulations required to achieve and implement boundaries and conditions of use and entry; and

Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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  • an assessment of the arrangements, including financial, human, and physical resources, required to implement the zones and manage them effectively.

The Planning Program

After an area has been chosen as a potential site for an MPA, there are five desirable stages in the development of a zoning plan (Kelleher, 1999):

    1. Initial information gathering and preparation. The planning agency, prepares a review of information on the nature and use of the area, including participation by various user groups, and develops materials for public distribution.

    2. Identification of zoning needs. This involves public comment on the accuracy and adequacy of review materials and discussion of the types of zoning that should be included in the plan.

    3. Preparation of draft plan. This plan defines specific objectives for each zone and identifies potential sites for these zones.

    4. Publication and review of draft plan. Public comments are gathered and used to revise the draft plan.

    5. Plan finalization. The government or agency adopts a revised plan that represents the best fit for meeting conservation needs and concerns of the general public and user communities.

The importance of public participation in planning cannot be overemphasized. Although public participation increases the expense and time involved in planning, it can save both time and expense in the long run by increasing the likelihood that the plan will be approved, implemented, and enforced (Kelleher and Kenchington, 1992). This will require the coordinating agency to identify the various stakeholder groups and develop strategies for working with these groups. For example, planning documents should be accessible, short, and presented in nontechnical, easily understandable language. Participatory mechanisms should not be limited to public hearings but should include less formal settings more conducive to open discussion. Finally, the concerns of stakeholders must be documented in the preparation of management plans (Suman et al., 1999).

In practice, management decisions will be based on incomplete knowledge and understanding; however, most plans involve some research to narrow the range of possibilities for MPA selection. If funds are limited, a competent plan can be developed with basic descriptions of the physical, biological, and socioeconomic characteristics of an area.

A management plan for an MPA will require revisions over time to address shortcomings in the performance of the MPA and advances in understanding of how the MPA contributes to resource management. Hence, some flexibility

Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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must be allowed for adjusting the zoning and levels of protection within MPAs. Lack of flexibility currently constrains the National Marine Sanctuary Program because of pledges not to restrict commercial fishing operations made during the designation of some sites (NAPA, 2000). Review of zoning plans and performance should be conducted at intervals short enough for management to respond to problems but not so frequent that it becomes prohibitively expensive—five to seven years is often a suitable period. Such a review should include monitoring impacts, patterns of use, and enforcement. The importance of a rigorous monitoring and evaluation program for the success of MPAs is explored in detail in Chapter 7.

Management Tools to Supplement MPAs

Until recently, the establishment of MPAs has not been viewed in the context of the marine ecosystem as a whole. In planning past MPAs, people have often failed to consider how the surrounding region and human activities may affect the MPA, and vice versa. However, good management of surrounding areas will increase the efficacy of MPAs. With precautionary management, a smaller total area in fully protected reserves may suffice to yield the same conservation benefit. Thus, it is essential to manage activities beyond an MPA's boundaries to secure its long-term viability.

One approach to coupling the use of MPAs with coastal zone management is to create contiguous marine and terrestrial protected areas. Local governments usually have an important role in controlling development and other activities in adjacent coastal areas, as a form of integrated coastal zone management. Because polluted runoff, drainage of wetlands, and diversion of freshwater streams and rivers negatively affect the health of adjacent marine areas, the success of an MPA will in part be dependent on the community's commitment to manage adjacent coastal areas to improve or maintain the quality of the marine environment.

The most obvious external influences that should be controlled include pollution and overutilization of living resources. Effort- and quota-based management, as well as additional spatial and temporal controls on fishing, can be applied to supplement protection using reserves. The type of additional measures needed to regulate fishing will vary widely among fish stocks and areas. Some of these other measures and their application are described in Chapter 3.

Many options will prove useful for spatially controlling fishing outside MPAs, such as establishing area and temporal closures to particular methods of fishing. Temporal closures have long been used in single-species fishery management. In contrast to permanent closures, they have been broadly accepted as a management tool. Temporal closures can be a primary means to try to confine catches to targeted levels or to distribute fishing effort over a season. In fact, within-season temporal closures, combined with gear restrictions, are among the

Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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most common methods used to control fishing effort. Temporal closures are also implemented to protect fishery resources at times when they are particularly vulnerable, such as when fish are aggregated on spawning grounds.

MPAs will also shift patterns of fishing effort, and management plans should be designed to take these expected changes into account. Temporal closures aimed at limiting fishing mortality can be effective if regulators correctly anticipate or control the fishery's reaction to time (and area) closures. A closure in one area will typically result in increased effort elsewhere.

In some cases, rotating areas of closure for specified periods has been used to promote growth of young animals, allowing them to reach more valuable sizes. This approach combines temporal and spatial closures to regulate fishing and could supplement benefits from fully protected reserves. As an example, the State of Washington has instituted rotating closures in its sea urchin fishery to control effort and allow populations to recover to marketable sizes and quantities. Rotating closures may help protect habitat and biological communities in addition to target species by allowing areas altered by fishing gear to recover during respites from fishing. However, if the period of closure is short, the area may have insufficient time to recover, jeopardizing the full recovery of the target stock.

Longer-term closures may be instituted as single-species refuges from fishing. In this approach, the goals focus on rebuilding or restoration, with long-term success dependent on more precautionary management after the stock recovers. One recent long-term closure in California, implemented for chinook salmon (Oncorhynchus tshawytscha) in the Klamath River area, closed the entire (mixed-species) salmon fishery off the coast to allow recovery. In another example, closure of the severely depleted striped bass (Morone saxatilis) fishery along much of the east coast of the United States in the 1980s was effective in promoting recovery of the species and reestablishment of the fishery (Field, 1997; Richards and Rago, 1999). Unfortunately, there are few alternatives to long-term closures of large areas when fish populations have collapsed, and restoration of the abundance and age structure of the depleted population may require many years. One goal of MPAs is to provide insurance against stock collapse (Chapter 5), reducing the need for such drastic measures.

Single-species closed areas lack many of the key conservation benefits of permanent reserves, but they provide an important tool to control fishing effort and supplement more comprehensive MPAs. There are some examples of temporal closures to address multispecies or ecosystem concerns rather than single-species fishery management. For instance, closure of large areas in the Bering Sea around Steller's sea lion (Eumetopias jubatus) habitat during the walleye pollock (Theragra chalcogramma) fishing season is an example of the use of temporal area closures with broader conservation objectives.

Although temporal closures have value as a tool for fishery management, this approach does not yield the benefits sought with the establishment of MPAs.

Suggested Citation:"Design." National Research Council. 2001. Marine Protected Areas: Tools for Sustaining Ocean Ecosystems. Washington, DC: The National Academies Press. doi: 10.17226/9994.
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There are cogent ecological and socioeconomic arguments for establishing MPAs with long-term, defined boundaries, although there has to be flexibility for adjusting zones, such as ecological or fishery reserves, within MPAs to maximize effectiveness. Damage to habitats and fish populations from human activities can occur very quickly, but recovery often requires a long period of time. For example, biogenic habitat such as deep-sea corals once damaged by trawling could take many decades to recover. Also, when fish stocks collapse, recovery may be slow, especially for long-lived species that take many years to reach reproductive maturity. If reserves are designed in the context of supporting the surrounding ecosystem they can serve as the ecological equivalent of a trust fund: the fish stocks and habitat within a reserve will provide a long-term investment in the productivity of the ecosystem as a whole.

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Next: Monitoring, Research, and Modeling »
Marine Protected Areas: Tools for Sustaining Ocean Ecosystems Get This Book
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Although the ocean-and the resources within-seem limitless, there is clear evidence that human impacts such as overfishing, habitat destruction, and pollution disrupt marine ecosystems and threaten the long-term productivity of the seas. Declining yields in many fisheries and decay of treasured marine habitats, such as coral reefs, has heightened interest in establishing a comprehensive system of marine protected areas (MPAs)-areas designated for special protection to enhance the management of marine resources. Therefore, there is an urgent need to evaluate how MPAs can be employed in the United States and internationally as tools to support specific conservation needs of marine and coastal waters.

Marine Protected Areas compares conventional management of marine resources with proposals to augment these management strategies with a system of protected areas. The volume argues that implementation of MPAs should be incremental and adaptive, through the design of areas not only to conserve resources, but also to help us learn how to manage marine species more effectively.

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