Pacific White-Sided Dolphin

Pacific white-sided dolphins are protected under the Marine Mammal Protection Act. They are not considered endangered or threatened under the Endangered Species Act. NOAA Fisheries and our partners work to conserve and protect this species in many ways.

A Pacific white-sided dolphin. Photo: Mark Malleson.

Dolphin-Safe/Tuna Tracking and Verification Program

Dolphins, like other marine mammals, may become bycatch in fisheries. Some species of tuna are known to aggregate beneath schools of certain dolphin stocks. In some parts of the world, this close association led to the fishing practice of encircling a dolphin school to capture the tuna concentrated below. The Dolphin Protection Consumer Information Act established a national tuna tracking program to ensure that tuna imported into the United States meets certain requirements to ensure the safety of dolphins during tuna fishing operations.

Learn more about the Dolphin-Safe/Tuna Tracking and Verification Program

Reducing Interactions with Fishing Gear

Bycatch in fishing gear is a leading cause of Pacific white-sided dolphin deaths and injuries. To reduce deaths and serious injuries from drift gillnet commercial fishing gear off the coast of California and Oregon, NOAA Fisheries implemented the Pacific Offshore Cetacean Take Reduction Plan in 1997. 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 the plan. The plan included skipper education workshops and required the use of pingers and minimum 6-fathom extenders to provide a net-free zone at surface waters for safe passage by dolphins. As a result, overall entanglement rates in the drift gillnet fishery dropped considerably.

Learn more about bycatch and fisheries interactions

Minimizing Harassment and Illegal Feeding

As human interactions with wild dolphins increase, so does the risk of disturbing or injuring these animals. NOAA Fisheries provides guidance on how to safely and responsibly view dolphins, including the following initiatives:

• The Protect Dolphins Campaign

• Don’t Feed Wild Dolphins

• Dolphin SMART program

Learn more about the rules regarding feeding and harassing marine mammals in the wild

Addressing Ocean Noise

Underwater noise threatens marine mammal populations, 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 cetaceans to strand and ultimately die. NOAA Fisheries researches aspects of acoustic communication and hearing in marine animals, as well as the effects of sound on marine mammal behavior and hearing. In 2018, we revised technical guidance for assessing the effects of anthropogenic (human-caused) 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 large whales. When stranded animals are found alive, NOAA Fisheries and our partners assess the animal’s health.  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 identify strandings due 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

Under the Marine Mammal Protection Act, an unusual mortality event (UME) 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

Pacific white-sided dolphins. Photo: NOAA Fisheries.

All Pacific white-sided dolphins are protected under the MMPA.

Before the United Nations issued a moratorium that banned large-scale drift nets in 1933, Japanese fisheries often captured Pacific white-sided dolphins. The MMPA was later enacted in 1972 to protect all marine mammals, severely reducing the amount of animals injured and/or killed. This species is now no longer commercially hunted in the United States, though some Pacific white-sided dolphins are still harvested for food in Japan's coastal fisheries.

In 1999, the United States signed on as a Party to the Agreement on the International Dolphin Conservation Program (AIDCP). In addition to other requirements, the AIDCP’s main objective is to reduce incidental dolphin mortalities in the tuna purse-seine fishery.

The International Dolphin Conservation Program Act (PDF, 19 pages) amended the MMPA to make AIDCP objectives and requirements legally effective in the United States.

NOAA Fisheries conducts research on the biology, behavior, and ecology of the Pacific white-sided dolphin. The results of this research are used to inform management decisions and conservation efforts for this species and other marine life.

Stock Assessments

Determining the size of Pacific white-sided dolphin populations helps resource managers determine the success of our conservation measures. NOAA Fisheries scientists collect population information from various sources and present the data in an annual stock assessment report. 

Aerial and Shipboard Surveys

Scientists use small aircraft and research vessels to spot Pacific white-sided dolphins and photograph them to identify individuals and record their seasonal distribution. Understanding this species’ distribution patterns helps managers establish measures to limit the overlap between fisheries and dolphins. This research can be used to inform management actions that protect the Pacific white-sided dolphin. A review of sighting reports and bycatch data from the Bering Sea suggests Pacific white-sided dolphin presence is not rare, occurs year-round, extends farther north than shown on current range maps, and that site-fidelity may occur in areas near and within Bristol Bay.

Research Projects

NOAA Fisheries scientists conduct guided research projects to answer questions about a particular ecosystem or ecology. For example, the Cetacean Assessment and Ecology Program conducts studies to assess the status of cetaceans in Alaskan waters under the Endangered Species Act and the Marine Mammal Protection Act, which includes the Pacific white-sided dolphin. The program uses the results of stock assessments, surveys, and studies to provide the scientific advice necessary to manage cetaceans in Alaskan waters.

Acoustic Science

Other research focuses on the acoustic environment of cetaceans, including the Pacific white-sided dolphin. Acoustics is the science of how sound is transmitted. This research involves increasing our understanding of the basic acoustic behavior of whales, dolphins, and fish; mapping the acoustic environment; and developing better methods to locate cetaceans using autonomous gliders and passive acoustic arrays.

Learn more about acoustic science