There continues to be congressional interest in limiting human activity in certain areas of the marine environment, as one response to mounting evidence of declining environmental quality and populations of living resources. The purposes of proposed additional limits would be both to stem declines and to permit the rehabilitation of these environments and populations. One method of implementing this concept is for Congress to designate areas where activities would be limited, often referred to as marine protected areas (MPAs). Translating the MPA approach into a national program, however, would require that Congress resolve many economic, ecological, and social dilemmas.

The Endangered Species Act (ESA) protects species identified as endangered or threatened with extinction and attempts to protect the habitat on which they depend. It is administered primarily by the Fish and Wildlife Service and also by the National Marine Fisheries Service for certain marine and anadromous species. Dwindling species are listed as either endangered or threatened according to assessments of the risk of their extinction. Once a species is listed, legal tools are available to aid its recovery and to protect its habitat. The ESA can become the visible focal point for underlying situations involving the allocation of scarce or diminishing lands or resources, especially in instances where societal values may be changing, such as for the forests of the Pacific Northwest, the waters in the Klamath River Basin, or the polar environment. This report discusses the major provisions of the ESA, both domestic and international, and also discusses some of the background issues, such as extinction in general, and the effectiveness of the statute.

Fish and marine mammals are important resources in open ocean and nearshore coastal areas; many federal laws and regulations guide their management. Bills to reauthorize and amend major legislation - the Magnuson-Stevens Fishery Conservation and Management Act (MSFCMA) and the Marine Mammal Protection Act (MMPA) - were acted upon by the 109th Congress; the authorization of appropriations for both laws expired at the end of FY1999. A bill offering extensive amendments to the MSFCMA was passed by both the House and the Senate (H.R. 5946) and awaits the President's signature; a bill extensively amending the MMPA was passed by the House (H.R. 4075). Commercial and sport fishing are jointly managed by the federal government and individual states. States have jurisdiction generally within 3 miles of the coast. Beyond state jurisdiction and out to 200 miles, the federal government manages fisheries under the MSFCMA through eight regional fishery management councils. Beyond 200 miles, the United States participates in international agreements relating to specific areas or species. Legislation related to commercial and sport fisheries enacted by the 109th Congress included measures to protect fishermen under bankruptcy law ( 1007 of P.L. 109-8), revise visa requirements to allow seasonal seafood processing workers to enter the United States ( 402 of P.L. 109-13 and 1074 of P.L. 109-364), reaffirm state authority to regulate fishing to distinguish between state and out-of-state residents ( 6036 of P.L. 109-13), allow hydropower licensees to propose alternatives to fishways as long as the alternatives would not diminish fish passage ( 241 of P.L. 109-58), provide $112 million for Gulf Coast fishery recovery (P.L. 109-234), amend the Sport Fish Restoration Program to permanently appropriate boat safety funding and modify distribution of funds (Title X of P.L. 109-59), and implement the Great Lakes Fishery Resources Restoration Study (P.L. 109-326). Aquaculture - the farming of fish, shellfish, and other aquatic animals and plants in a controlled environment - is expanding rapidly, both in the United States and abroad. In the United States, important species cultured include catfish, salmon, shellfish, and trout. Legislation related to aquaculture enacted by the 109th Congress protects aquaculture under bankruptcy law ( 1007 of P.L. 109-8) and clarifies aquaculture grants for 2005 hurricane disaster relief ( 3032 of P.L. 109-234). Marine mammals are protected under the MMPA. With few exemptions, the MMPA prohibits harm or harassment ("take") of marine mammals, unless restrictive permits are obtained. It addresses specific situations of concern, such as dolphin mortality, primarily associated with the eastern tropical Pacific tuna fishery. No marine mammal legislation was enacted by the 109th Congress. This report replaces CRS Issue Brief IB10139, Fishery, Aquaculture, and Marine Mammal Legislation in the 109th Congress, by Eugene H. Buck.

On May 14, 2008, Interior Secretary Dirk Kempthorne announced the listing of polar bears as threatened under the Endangered Species Act (ESA). The controversial decision highlights the intersection of two significant issues currently before Congress - climate change and species protection. Under the ESA, a listing decision must rest solely on the best available scientific information concerning the species. Habitat loss has been a major reason for many decisions to add species to the list - in this case, loss of Arctic sea ice. The listing itself was praised by some environmentalists, who nonetheless deplored interim protective regulations for the polar bear as being too weak. Other parties, who opposed the listing itself, argued that the science supporting listing was weak, but felt that the regulations mitigated some of the economic impacts of the listing.