Harbor Porpoise

Reducing Interactions with Fishing Gear

Bycatch in fishing gear is a leading cause of harbor porpoise deaths and injuries. To reduce deaths and serious injuries of harbor porpoises from gillnet fisheries, NOAA Fisheries implemented the Harbor Porpoise Take Reduction Team.

Representatives from NOAA, the fishing industry, regional fishery management councils, state and federal resource management agencies, the scientific community, and conservation organizations worked together to develop a plan to reduce harbor porpoise bycatch. The plan includes regulations, such as seasonal gillnet restrictions, closures, and the use of acoustic deterrent devices called pingers. The group that developed the Harbor Porpoise Take Reduction Plan continues to meet to monitor the progress of the take reduction plans in achieving the MMPA long-term goal of reducing harbor porpoise bycatch to a zero mortality and serious injury rate.

Learn more about bycatch and fisheries interactions

Addressing Ocean Noise

Sound pollution threatens harbor porpoise populations by interrupting their normal behavior and driving them away from areas important to their survival. Increasing evidence suggests that exposure to intense underwater sound in some settings may cause some porpoises to strand and ultimately die. NOAA Fisheries is investigating all aspects of acoustic communication and hearing in marine animals. In 2018, we revised technical guidance for assessing the effects of anthropogenic sound on marine mammal hearing.

Learn more about ocean noise

Overseeing Marine Mammal Health and Stranding Response

We work with volunteer networks in all coastal states to respond to marine mammal strandings including all dolphins and porpoises. When stranded animals are found alive, NOAA Fisheries and our partners assess the animal’s health and determine the best course of action. When stranded animals are found dead, our scientists work to understand and investigate the cause of death. Although the cause often remains unknown, scientists can sometimes attribute strandings to disease, harmful algal blooms, vessel strikes, fishing gear entanglements, pollution exposure, and underwater noise. Some strandings can serve as indicators of ocean health, giving insight into larger environmental issues that may also have implications for human health and welfare.

Learn more about the Marine Mammal Health and Stranding Response Program

Marine Mammal Unusual Mortality Events

Harbor porpoise have been part of a declared unusual mortality event in the past. Under the Marine Mammal Protection Act, an unusual mortality event is defined as "a stranding that is unexpected; involves a significant die-off of any marine mammal population; and demands immediate response." To understand the health of marine mammal populations, scientists study unusual mortality events.

Get information on active and past UMEs

Get an overview of marine mammal UMEs