Page 462 - Environment: The Science Behind the Stories

WeIGhING the ISSUeS We can protect areas in the ocean

eatING SeaFOOd After reading this chapter, do you plan to Hundreds of marine protected areas (Mpas) have been estab-
alter your decisions about eating seafood in any way? If so, lished, most of them along the coastlines of developed coun-
how? If not, why not? Do you think consumer buying choices tries. However, despite their name, nearly all MPAs allow
can exert an influence on fishing practices? On mercury con- fishing or other extractive activities. As one report from an
tamination in seafood? environmental advocacy group put it, MPAs “are dredged,
trawled, mowed for kelp, crisscrossed with oil pipelines and
fiber-optic cables, and swept through with fishing nets.”
Marine Conservation Because of the lack of true refuges from fishing pres-
sure, many scientists want to establish areas where fishing
Because we bear responsibility and stand to lose a great deal is prohibited. Such “no-take” areas have come to be called
if valuable ecological systems collapse, marine scientists marine reserves. Designed to preserve ecosystems intact,
have been working to develop solutions to the problems that marine reserves are also intended to improve fisheries. Scien-
threaten the oceans. Many have begun by taking a hard look tists argue that marine reserves can act as production factories
at the strategies used traditionally in fisheries management. for fish for surrounding areas, because fish larvae produced
inside reserves will disperse outside and stock other parts of
the ocean. By serving both purposes, proponents maintain,
Fisheries management has been based marine reserves are a win-win proposition for environmental-
on maximum sustainable yield ists and fishers alike.
Many commercial and recreational fishers dislike the idea
Fisheries managers conduct surveys, study fish population of no-take reserves, however, just as most were opposed to
biology, and monitor catches. They then use that knowledge the Canadian groundfish moratoria and the Georges Bank clo-
to regulate the timing of harvests, the scale of harvests, and the sures. Nearly every marine reserve that has been established or
techniques used to catch fish. The goal is to allow for maximal proposed has met with opposition from people and businesses
harvests while keeping fish available for the future—the con- who use the area for fishing or recreation. Some protests have
cept of maximum sustainable yield (p. 333). Recall that this turned violent. To protest fishing restrictions, fishermen in the
means keeping populations at about half the level they would Galápagos Islands destroyed offices at Galápagos National
otherwise achieve, because populations growing by logistic Park and threatened researchers and park managers with death.
growth grow fastest at this size (pp. 85–86). If data indicate Clearly, when marine reserves are established, it pays to
that current yields are unsustainable, managers might limit the be sensitive to the concerns of people of the area. In 2006,
number or biomass of fish that can be harvested, or they might President Bush established the Papahanaumokuakea Marine
restrict the type of gear fishers can use. National Monument around the northwestern Hawaiian
The science of estimating population sizes of species such Islands—at 362,000 km (140,000 mi ), an area larger than all
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as cod is imprecise and can lead to significant changes in maxi- U.S. national parks combined. In this new monument, native
mum sustained yield. For example, the cod population in the Hawaiians were given fishing rights in areas where fishing
Gulf of Maine was sampled in 2008 and its biomass estimated was otherwise made off-limits.
at 34 million kg (74.9 million lb). Allowable harvests by fisher- In contrast, the United Kingdom in 2010 established the
men were set based on this survey, but a subsequent survey in world’s largest marine reserve around the Chagos Archipelago,
2011 concluded cod biomass in the Gulf to be only 12 million a group of 55 islands it controls in the Indian Ocean. The indig-
kg (24.6 million lb). This reduction was not explainable by fish enous people of these islands were forcibly evicted from the
harvests over the three years, so resource managers concluded main island, Diego Garcia, between 1967 and 1973 so that the
that the 2008 survey overestimated cod populations based on United States could build a military base there. The roughly
a few large trawls, many of which have not been indicative of 4000 Chagossian people have been fighting in courts ever since
true cod numbers. In light of the new assessment of cod bio- for the right to return to their islands. They now fear that with CHAPTER 16 • M AR in E A nd Co A s TA l s ys TEM s A nd R E sou R CE s
mass, fishing quotas were lowered, forcing fishermen in the fishing banned, they will never be able to return because there
area to quickly adapt to new levels of allowable catch. Simi- would be no way to make a living. The U.K. government has
lar overestimates occurred in cod populations in the Georges
Bank population at the same time, with similar outcomes.
Despite efforts to restrict fish harvests to sustainable lev- WeIGhING the ISSUeS
els, a number of fish and shellfish stocks have plummeted. pReSeRvatION at Sea Almost 4% of U.S. land area is des-
Thus, many scientists and managers feel it is time to shift ignated as wilderness, yet before the recent actions in Hawaii
the focus away from individual species and toward viewing and the Chagos Islands, far less than 1% of coastal waters
marine resources as elements of larger ecological systems. were protected in reserves. Why do you think it is taking so
This perspective means considering the impacts of fishing long for the preservation ethic to make the leap to the oceans?
practices on habitat quality, species interactions, and other What challenges do you see with preserving areas of coastal
factors that may have indirect or long-term effects on popula- ocean? Do you think local people should be given fishing
tions. One key aspect of such ecosystem-based management rights in marine reserves? What could be done to better pro-
(p. 333) is to set aside areas of ocean where systems can func- tect marine ecosystems, fisheries, and local fishing cultures?
tion without human interference. 461

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