Marine Protected Areas as Effective Fishery Management Tools
The marine protected area system is an integral part of the CNMI's coastal zone management program. Our marine sanctuaries, reserves, and conservation areas provide a tool to manage human activities and sustain multiple fishery species using an ecosystem-based management approach. Managing fisheries on a species-by-species basis can be very difficult. Therefore managing them as a whole through managing the ecosystem is the most efficient and cost-effective method. Furthermore, no take zones are much simpler to monitor and enforce than conventional fishing regulations such as gear and harvest restrictions. This is particularly true in the CNMI where such a large area of the sea and reef requires surveillance.
No-take zones where fishing is prohibited can enhance fishing in surrounding areas in a number of ways. First, fish are more abundant in the no take zones and grow to a larger size, since fishermen don't remove them. By protecting reef fish stock within marine sanctuaries, fish live longer and grow larger. Generally, bigger fish produce more eggs and offspring than smaller fish and the greater number of fish in the sanctuary will produce more offspring overall. These larvae are not strong enough to swim faster than ocean currents so many of them may be carried out of the no take zone. As the larvae develop into adults, they help replenish the surrounding fishing grounds and can be captured by fishermen.
Second, inside no take zones the density of fish can increase to the point where things become too crowded. Fish compete more intensively for food and suitable habitat. As a result, some adults and juveniles will "spillover" into adjoining areas and become available for capture and harvest.
On many of our coral reefs, high fishing pressure has changed the natural community structure, damaged habitats and removed some of the large target species such as groupers. By prohibiting fishing and destructive practices in marine protected areas, important habitat and fish stocks can restore themselves and the ecosystem can return to its natural functioning state.
Third, fishery management is bedeviled by uncertainty. In order to determine harvest levels that do not result in over-fishing, fishery managers need to accurately estimate the population size of the fish being caught and some of their biological characteristics, such as how fast they grow. Getting this information is difficult because the fish are hidden underwater and may swim long distances. In addition, population size can fluctuate widely due to environmental conditions such as typhoons, ocean warming, and volcanoes. At the least, no take zone sanctuaries provide an "insurance policy" to mitigate these uncertainties.
Studies in Guam, Fiji and throughout the Pacific have shown that the weight of fish per unit area was far greater in marine protected areas than at other sites. Fish were more abundant, and there were more species present than in fished areas. Other studies have shown that populations of lobster, conch and shellfish within protected areas increased significantly, demonstrating that these areas had recovered from over-fishing. In Fiji, no take zone sanctuaries have increased fish catch for villagers dependent on fisheries for food, and in Florida recreational fishing has improved dramatically with the inception of their marine sanctuaries program.
Fourth, marine protected areas can protect vulnerable species and habitat critical to their survival. These organisms may naturally exist in low numbers or have become endangered as a result of man's activities. Others may be relatively abundant but their biological characteristics-slow growth or low fecundity (few offspring)-make them especially susceptible to over-harvest. Sea Turtles for example, take over a decade to grow and mature to a point where they lay eggs. Then, they only lay their eggs at the beaches where they were born. By that time, the beach may have eroded or been replaced by man with housing or commercial establishments, or predators may eat the turtle or its eggs before they have a chance to replenish the population. In some instances a fully developed network of sanctuaries and conservation areas could replace other management measures. For example, if a significant proportion of a population were protected in no take zones, there might be less need to set harvest limits and restrictions, which can be hard to accurately determine and expensive to enforce.
Fifth, removing species directly, whether due to fishing, habitat damage or pollution, affects biodiversity (species richness) in an area. A species doesn’t have to go extinct for biodiversity to be diminished in any given area. If an organism's home range is reduced, ecosystems in those places where it no longer occurs are less diverse and less diverse ecosystems are often less productive. Removing species can also have indirect effects. For example, if a predator disappears its prey can proliferate, displacing other species. Alternatively, if one of two competing species is removed, the other will dominate the ecosystem and may imbalance the system making it less productive.
Sixth, many human activities, especially certain fishing methods, can damage fish and reef habitat. Even recreational activities can cause harm, if they result in anchor damage to sensitive reef areas, boat groundings, littering, or trampling of bottom-dwelling organisms by inexperienced snorkelers and divers. If these activities are restricted within marine protected areas, damage is less likely to occur. However, marine protected areas cannot prevent pollution originating outside their boundaries from harming habitat. The no take zone boundaries will not turn away oil spilled in an adjacent area or sediment and polluted water that runs off from land during heavy rainstorms.
Seventh, marine protected areas can directly benefit people by enhancing recreational opportunities and protecting cultural resources. People seeking to enjoy the natural environment expect scenic beauty and minimal evidence of human impacts. By prohibiting destructive uses, marine sanctuaries and conservation areas help sustain this concept of nature. In the CNMI, marine protected areas protect important cultural sites such as shipwrecks and Indigenous burial sites and permit traditional practices such as Fiirourow.
The existence of more, larger and many different types of fish makes marine protected areas very attractive for diving and snorkeling, and thus enhances the tourism industry. Based on their benefits to the fishing and tourism industries, marine protected areas are a good investment for the CNMI. They are similar to no-hunting areas within terrestrial wildlife conservation areas. Fishing rights, like hunting rights, must be balanced with conservation needs, the rights of other marine resource users, and the rights of future generations to have sustainable resources. Marine protected areas provide a good means of protecting these rights. No take zones ensure the protection of marine bio-diversity, which is the source ultimately of all fisheries productivity, the source of marine life that attracts divers and snorkelers, and provides the basis for our unique island culture and lifestyle.
The Marine Sanctuaries program at DFW has supported the formation of Advisory Committees for all no take zones to ensure input from stakeholders and those parties affected by the establishment of marine sanctuary’s and conservation areas. DFW encourages the public and these stakeholders to actively participate in the planning, management and enforcement of protected areas. By reinforcing social and cultural lines of enforcement, balanced use, and fisheries management, our marine protected areas can sustain our needs today and the needs of generations to come. Please help support and promote the No Take Zone policy by participating, whether directly as an informed stakeholder, or passively by respecting the restrictions in marine sanctuary’s, conservation areas, and reserves. It’s the right thing to do! And, it’s the law!
(NOTE: This used to be on a CNMI Government Agency website, but they took it down.)