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Can Ecosystem Management of Coral Reefs be Achieved?

Charles Birkeland

Coral reef ecosystems have the highest gross primary productivity in the sea, but the net productivity and potential fisheries yield are relatively low. The low net productivity in coral reef ecosystems is because of their complexity and diversity. A high diversity of phyla leads to a more complete partitioning and consumption of resources. A major portion of the primary productivity in the coral reef ecosystem is based on recycling of chemicals between algal symbionts and a variety of animal phyla. Coral reef communities are characterized by about six trophic levels and a disproportionate prevalence of predatory species, and much of the energy is lost in transfer among trophic levels rather than exported from the ecosystem. Coral reef ecosystems differ qualitatively and fundamentally from other ecosystems and the appropriate management strategies for coral reef ecosystems must also differ from the traditional species-by-species management plans.

Vulnerability of Coral Reef Species and Ecosystems

Populations of animals on coral reefs can be fished down quickly and if severely depleted, may not return. For example:

• Fish populations on a newly discovered pinnacle off northwestern Guam were monitored when fishing began in 1967. The populations were fished down in about six months. They have been monitored ever since by the Government of Guam's Division of Aquatic and Wildlife Resources and it has been documented that the populations have not recovered after 34 years.
• Likewise, a grouper spawning aggregation was extirpated by a Taiwanese fishing boat in the Denges Channel of Palau in 1986 and the population has not returned after 15 years.
• Over a hundred tons of Pinctada margaritifera (the black-lipped pearl oyster) were taken from the population on Pearl and Hermes Reefs in the NW Hawaiian Islands in 1927. Paul Galtsoff found several hundred survivors in 1930, but only a few were found during a NMFS survey in 1993 and six were found during an intensive survey late in the year 2000.
• Hundreds of tons of sea cucumbers were harvested from Truk (now Chuuk) Lagoon in the late 1930s, but only two individuals of the valuable species Holothuria nobilis were observed in a survey of eight sites in 1988.
• The kupuna (master fisherman) Louis Agard tells of finding a school of large moi (Polydactylus sexfilis) at Shark Island in the French Frigate Shoals, Northwest Hawaiian Islands in the early 1950s. He caught the school and never saw more moi there, although he continued to fish the area for ten years. He tells of how he learned from numerous examples of the fragility of the reef fishery resources and how one fishing boat can make permanent changes.

The vulnerability of coral-reef species is partly because of their life-history adaptations to uncertainty in survival of recruits and juveniles in diverse communities where predation and competition are intense. With low rates of survival of recruits, multiple attempts at reproduction are favored through longevity and large size. These traits lead to low rates of population turnover and special vulnerability to overfishing.

Because of the life-history traits of the targeted species and because of the nature of the ecosystem processes, we must be careful about expecting too much from coral reefs. Even though they have the highest gross primary production of marine habitats, the fisheries yield of coral reefs should not be expected to keep pace with the growing human population and its demand for protein.

Another special consideration is the effects of overfishing on food-web dynamics or ecosystem function, and multispecies assemblage composition. Unlike pelagic fishery systems, overfishing a coral reef can have ecosystem-level effects. Examples of alternate stable states of algae resulting in part from overfishing of herbivores are found around Ngaderrak Reef in Palau which began with a crown-of-thorns outbreak in 1979, and the north coast of Jamaica which began with multiple factors in the early 1980s. Pelagic species might be managed on a species-by-species basis, but because of ecosystem-level effects resulting from coral-reef fisheries, the coral reef must be dealt with using an ecosystem approach. The maximum sustained yield for reef fisheries may not correspond with the level at which the species may be harvested without ecosystem overfishing. (Ecosystem overfishing occurs when overfishing affects multispecies assemblage composition, food-web dynamics, or ecosystem function.)

Shortcomings in U.S. Fisheries Management for Coral Reefs

The marine fisheries in the U.S. are managed under the Magnuson-Stevens Fishery Conservation and Management Act (as amended 11 October 1996). The Magnuson-Stevens Act requires the management units to be species or taxonomic groups, with a maximum sustained yield calculated for each. Unless identified with a specific maximum sustained yield, the resource will not be considered to be regulated or managed. This may work for north temperate fisheries for which the Magnuson-Stevens Act was originally designed, but these criteria do not work for coral-reef fisheries where bioprospecting harvests new unnamed resources, new technologies such as mixed gas diving open up new resources, multispecies interactions bring about unpredicted ecosystem overfishing, ecosystem overfishing does not necessarily correspond with maximum sustainable yield, and recruitment is erratic and unpredictable. The temperate fisheries are mainly for food resources, but in addition to food, coral-reef fisheries are for pharmaceuticals, ornamentals, and aquaculture brood stock. In temperate regions, catch per unit effort is often used as a proxy for overfishing, but it has yet to be shown as a reasonable proxy for ecosystem overfishing.

Ecosystem-Based Coral Reef Management in the Western Pacific

The Coral Reef Ecosystem Fishery Management Plan (CREFMP) for the western Pacific is the first ecosystem-based fishery management plan for U.S. waters. Its objectives are to:

• develop sustainable use of multispecies coral-reef resources, especially by indigenous fishermen and local fishing communities,
• prohibit destructive fishing methods,
• develop integrated data collection on resources,
• <>develop cooperative and coordinated management of resources and information among agencies, and
• provide education of the public in order to foster support for responsible management.

The CREFMP is not only focused on management of food resources, but also on new creative endeavors such as pharmaceuticals, live rock, live fish trade for restaurants and ornamentals, and aquaculture brood stock. Because of the complexity of the coral-reef system and the rapid development of new and unexpected technological advances, the strategy must be to preempt, but facilitate, the management of unknown resources.

The approach of the Magnuson-Stevens Act is that resources are open to unmanaged exploitation until the resource is named and a maximum sustained yield is calculated (Magnuson-Stevens Act Section 303). In the CREFMP, we take the opposite approach, a precautionary approach, with the Permitting System in which a plan must be developed before the harvest can proceed. A committee of scientists should examine potential ecosystem effects before a permit is given. To assess potential effects, the committee may consider the interactions of the resource with the trophic levels below and above. If the resource is harvested, does this release the prey of the resource species from its regulation (e.g., if a herbivore is harvested, does this potentially release algae from control to the extent that it shifts the system into an alternate state where algae inhibit coral recruitment?) If the resource is harvested, are humans competing with the natural predators of the resource (e.g., does the harvest of spiny lobsters from the Northwest Hawaiian Islands substantially reduce the food supply of the endangered monk seal?) Each resource should be examined in terms of its role in the ecosystem. Does it provide structure and topographic complexity? Does it have symbionts? The burden of proof is reversed when a plan must be provided before a permit is granted. Enforcement is enhanced by the information provided in the reporting process required by the permit. If there were no report, the permit would not be renewed.

Coral-reef ecosystems are too complex to completely understand, but the permitting system continuously provides new information through the reporting process. Permit forms require the catch to be reported, and as the information is compiled, changes over time in catch per unit effort and size distribution of the resource allows management to improve. Scientific study or monitoring of all fisheries programs would be prohibitively expensive, but the required reporting of catch and bykill provides an inexpensive source of information. A permit may be revoked or modified at any time it becomes evident that the harvest is having deleterious effects on the ecosystem. A permit may also be revoked or modified if unseen natural events such as the El Niˆ±o Southern Oscillation or a typhoon occur. The permit system allows for adaptive management, whereas regulations are more difficult to change quickly, as new information becomes available. The CREFMP also provides flexibility in the management by providing a framework process involving administratively simplified procedures for changing regulations.

Marine Protected Areas

The CREFMP for the western Pacific has taken a holistic ecosystem approach by establishing Marine Protected Areas (MPAs). In the 1200-mile long Northwest Hawaiian Island chain, no-take MPAs are at 0 to 10 fathoms (to 60-foot depths) for all the chain. No-take MPAs are also from 10-50 fathoms (to 300 ft) at French Frigate Shoals, Laysan, and the northern half of Midway. The southern half of Midway is only for recreational catch and release. The no-take MPAs at remote Pacific islands (Jarvis, Baker, Palmyra, Howland, Kingman, and Rose Atoll) are from 0 to 300 feet. The no-take MPAs are holistic in that they allow natural process to be maintained without needing detailed knowledge of each species, multispecies interactions, or ecosystem functions, and they provide insurance against unpredicted climatic events and irregularities in recruitment. Enforcement is easier with MPAs than with quotas and gear restrictions, and MPAs constitute areas that are informative on how the natural system works in the absence of exploitation by humans.

MPAs are touted for two contradictory purposes, to preserve biodiversity (greater gross primary productivity, but reduced net productivity or yield) and to preserve and enhance fisheries yield (less gross primary productivity, but increased net productivity or yield).

Coral reefs in other areas of the Exclusive Economic Zone of U.S. waters are categorized as low-use MPAs. They can be harvested within fishery management plans that have already been developed (bottomfish, crustacean, and precious coral fisheries). Except for these fisheries, any take and scientific research require a special permit as described above. Low-use MPAs are from 60 to 300 ft on at the Northwest Hawaiian Island chain except French Frigate Shoals, Laysan and the northern half of Midway. Recreational fishing is allowed at Johnston, Wake and Guam southern banks.

Keeping Up with New Technologies

The CREFMP for the western Pacific takes the approach of approving gear rather than prohibiting gear because technology is developing so rapidly that new gear would be put into use faster than it could be examined, tested, and prohibited if necessary. (An example of new gear that has had devastating effects before there was time to prohibit it was the hunting of lumphead parrotfishes and Napoleon wrasses with nightlights and scuba at American Samoa and Guam). Just as the permit system is the reverse of the regulatory system (in the permit system, a resource cannot be harvested until a management plan is accepted), the CREFMP allows harvest only with gear that has been approved. New inventions are not given free use until prohibited, they are only allowed after approval. (In order to emphasize the explicit prohibition of gears that are destructive of habitat, the CREFMP prohibits dredges, trawls, poisons, gillnets, tanglenets, and explosives.)

Another tactic for general habitat protection stipulated by the CREFMP is that all fishing vessels are required to post bond or carry insurance to cover the expense of repair to the reef in case of grounding.

Summary

The ecosystem approach of the CREFMP for the western Pacific, as submitted by the plan team to the Western Pacific Regional Fishery Management Council, includes the permit system, marine protected areas, essential fish habitat, marine habitats of particular concern, bonds for fishing vessels, and a list of allowable gear. It is hoped that this plan is not substantially altered as it progresses through the administration for approval. It fulfills the policies advocated in the Report to Congress from the Ecosystem Principles Advisory Panel of the National Marine Fisheries Service: change the burden of proof, apply the precautionary approach, purchase "insurance" against unforeseen ecosystem impacts, and apply adaptive management.