Oceans & Coastal Resources:
A Briefing Book
Congressional Research Service Report 97-588 ENR
Redistributed as a service of the National Library for the Environment

Marine Mammal - Fisheries Interactions

Prepared by Eugene H. Buck

Senior Analyst in Natural Resources Policy
Environment and Natural Resources Policy Division


Issue Definition
Background and Analysis
Status of the Issue
Continuing Concerns
Sources and References for Further Information

Issue Definition

Human harvesting of fish and shellfish has the potential to disturb or harm some marine mammals, sometimes to the extent of potentially endangering populations (e.g., Gulf of Maine harbor porpoise) or species (e.g., Gulf of California vaquita). Any taking of marine mammals in waters under U.S. jurisdiction or by U.S. citizens anywhere is regulated under the authority of the Marine Mammal Protection Act (MMPA), and commercial fishery interactions are carefully scrutinized. A primary objective of the MMPA is to reduce marine mammal mortalities and injuries from commercial fishing operations to levels approaching zero, although this often places these efforts into direct conflict with the economics of the fisheries concerned. Thus, how best to minimize marine mammal mortality caused by commercial fishing can be a controversial issue.

Background and Analysis

Large numbers of marine mammals have been and are still being killed through incidental entanglement in fishing gear. Critical behaviors of other species (e.g., Steller's sea lion) may be disturbed by commercial fishing activities. In 1994, P.L. 103-238 was enacted to provide a new regime for incidental taking of marine mammals by the commercial fishing industry, including:

Status of the Issue

On May 5, 1995 (60 Federal Register 22345), NMFS published proposed guidelines and prohibited measures for safely deterring marine mammals from damaging fishing gear or catch. Proposed regulations for implementing the new requirements governing commercial fishery interactions with marine mammals along with the list of fisheries by category (1)based on levels of incidental mortality and serious injury) proposed for 1996 were published on June 16, 1995 (60 Federal Register 31666). The former interim exemption for commercial fisheries from the MMPA's general prohibition against taking marine mammals was scheduled to expire on September 1, 1995. The new regulations were promulgated on August 30, 1995 (60 Federal Register 45086) and the final list of fisheries by category was published on December 28, 1995 (60 Federal Register 67063), with an extension of the effectiveness of the 1995 list through March 1, 1996. This list of fisheries is updated each year by NMFS, with the most recent appearing on January 2, 1997 (62 Federal Register 33).

A problem with sea lions at Ballard Locks in Puget Sound, WA, generated much controversy. In June 1994, Washington state officials wrote to Secretary of Commerce Brown recommending that 3 to 6 individually identifiable California sea lions be killed to protect the steelhead trout run at Ballard Locks. In response, NMFS established a Pinniped-Fishery Interaction Task Force to consider whether to recommend that NMFS authorize the intentional lethal taking of individual sea lions. In January 1995, NMFS gave the State of Washington permission to kill California sea lions, after all feasible and practical non-lethal removal methods have been exhausted. After an official of the Humane Society of the United States stated that this organization would go to court to stop any killing, NMFS agreed to provide $120,000 to Washington state for temporarily holding nuisance sea lions during the summer of 1995. In January 1996, Washington state officials announced that funds were not available to capture and hold problem sea lions and that individual problem animals might have to be killed to protect migrating steelhead trout. After five individually identifiable sea lions were named as targets for action, the Progressive Animal Welfare Society (Seattle chapter), the Humane Society of the United States, and Earth Island Institute filed suit in federal court to prevent killing of any sea lions, claiming NMFS has not demonstrated that no feasible alternatives to killing exist. Subsequently, Sea World of Florida proposed, and NMFS and Washington state's Department of Fish and Wildlife accepted the offer, to permanently hold captive the five sea lions identified for killing. Three of the five sea lions were captured during May 1995, and subsequently transported for captive holding at Sea World of Florida.

On August 1996, NMFS announced the formation of a Take Reduction Team to address concerns that fishery interactions with northern right whales and humpback whales are resulting in excessive mortality. The four fisheries of concern were the Gulf of Maine/U.S. mid-Atlantic lobster trap/pot fishery, the mid-Atlantic coastal gillnet fishery, the southeastern U.S. Atlantic shark gillnet fishery, and the Gulf of Maine sink-gilinet fishery. Subsequent efforts intensified after U.S. District Court Judge Douglas Woodlock, in September 1996, found Massachusetts in violation of the federal Endangered Species Act for issuing permits for lobster and gilinet gear known to kill right whales. Massachusetts was ordered to prepare a detailed plan of action outlining how protection for right whales would be improved by restricting, modifying, or eliminating the use of lobster gear, gill nets, and other damaging fishing gear, or face a possible ban on certain fishing in state coastal waters. In April 1997, NMFS published a proposed take reduction plan and implementing regulations for northern right whales, humpback whales, fin whales, and minke whales that would restrict fishing times in whale habitat off New England and the mid-Atlantic in Cape Cod Bay, the Great South Channel, and several other areas. In addition, fishing gear modification would be required to allow whales to break free of gear in case of incidental entanglement, and response and assistance for entangled whales would be improved. Maine officials contend the required gear modification will cost the lobster industry between $40 million and $70 million.

Continuing Concerns

These concerns and questions are provided to stimulate further discussion of the issues noted above.

  1. The incremental costs of reducing mortality and injury to marine mammals by the commercial fishing industry continue to rise. Given the inevitability of rising costs, how stringently should Congress direct efforts toward the goal of zero mortality and injury? Imprecise data complicate such decision-making. How might more reliable data be obtained on marine mammal populations at a reasonable cost? How should management policy be formulated in the absence of these data?
  2. Should all fishery management plans prepared under the authority of the Magnuson-Stevens Fishery Conservation and Management Act be required to consider food (fish) requirements of current and expected populations of resident marine mammals? How might marine mammal management be better integrated with fishery management strategies at both the federal and state levels? In particular, what funding is required to study marine mammal interactions with ESA-listed anadromous salmon and trout?
  3. Marine mammals and their habitats are affected by both human activities and by natural catastrophic events. How should Congress determine the level and balance of funding between research on the degree to which some human activities (e.g., large commercial harvests of fish upon which marine mammals feed) indirectly harm marine mammals by altering ecosystems, and research on the degree to which natural catastrophic events (e.g., El Nino, Mississippi River flooding) harm marine mammals by altering the ecosystems?

Sources and References for Further Information

Griffin, Rodman D. "Marine Mammals vs. Fish." CQ Researcher, v.2, no.32 (Aug. 28, 1992): 739-758.

Iudicello, Suzanne. "Incidental Take of Marine Mammals in Commercial Fishing Operations: The Problems, the Solutions." Marine Conservation News, Autumn 1993: 11-14.

U.S. Library of Congress, Congressional Research Service. The Marine Mammal Protection Act: Reauthorization Issues. CRS Report for Congress 93-185 ENR. [by Jennifer Heck and Eugene H. Buck.) Washington, DC: Feb. 1, 1993. 37 p.

------------. Marine Mammal Protection Act Amendments of 1994. CRS Report for Congress 94-751 ENR. [by Eugene H. Buck.] Washington, DC: Sept.28, 1994. 11 p.

U.S. Marine Mammal Commission. Annual Report to Congress, 1996. Washington, DC: Jan.31, 1997. 247 p.

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