Pantropical Spotted Dolphin

Like all marine mammals, the pantropical spotted dolphin is protected under the Marine Mammal Protection Act. The Pacific northeastern offshore stock is listed as depleted under the MMPA. NOAA Fisheries is working to conserve this species to ensure populations remain stable.

Pantropical spotted dolphins observed during the 2017 Hawaiian Islands Cetacean and Ecosystem Assessment Survey. Photo: NOAA Pacific Islands Fisheries Science Center/Amanda L. Bradford.

Reducing Interactions with Fishing Gear

Pantropical spotted dolphins are caught as bycatch in fishing gear, leading to deaths and serious injuries, especially in the eastern tropical Pacific. NOAA Fisheries works with fishermen, industry, nongovernment organizations, and academia to find approaches and strategies for reducing bycatch in U.S. fisheries.

Learn more about bycatch and fisheries interactions

Overseeing Marine Mammal Health and Stranding Response

We work with volunteer networks in all coastal states to respond to marine mammal strandings. 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

Minimizing Harassment and Illegal Feeding

As human interactions with wild dolphins increase, so does the risk of disturbing or injuring these animals. The Hawaiian stock of pantropical spotted dolphins is especially vulnerable to disturbance and harassment from tourists. NOAA Fisheries provides guidance on how to safely and responsibly view dolphins, including the following initiatives:

• The Protect Dolphins Campaign
• Dolphin SMART program

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

Implementing the Dolphin-Safe/Tuna Tracking and Verification Program

Pantropical spotted dolphins, like other marine mammals, may become bycatch in fisheries. Some species of tuna are known to aggregate beneath schools of northeastern offshore spotted dolphin stocks in the ETP. This close association led to the fishing practice of encircling a spotted 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. The program helps ensure the safety of dolphins—such as the northeastern offshore spotted stock—during tuna fishing operations.

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

NOAA Fisheries and its partners are committed to research to help us better understand pantropical spotted dolphins and the challenges they face.

A pantropical spotted dolphin in Mariana Islands, Guam. Photo: NOAA Pacific Islands Fisheries Science Center/Adam Ü.

Stock Assessments

Determining the size of pantropical spotted dolphin populations helps resource managers determine the success of NOAA Fisheries’ conservation measures. Our scientists collect and present these data in annual stock assessment reports.

Shipboard Studies

NOAA’s Southwest Fisheries Science Center has conducted over 10 cetacean and ecosystem assessment surveys to collect information on pantropical spotted dolphins in the eastern tropical Pacific Ocean. The primary objective of these surveys is to investigate trends in population size of those dolphin stocks most affected by the tuna purse-seine fishery. The project takes a multidisciplinary approach. The SWFSC collects data on cetacean distribution, school size, and school composition to determine dolphin abundance. We also collect data on dolphin behavior to determine how that behavior influences our ability to detect dolphin schools and how dolphins respond to research vessels. Oceanographic data are collected to characterize habitat and its variation over time. Data on the distribution and abundance of prey, fishes and squids, seabirds, and marine turtles further characterize the ecosystem in which these dolphins live. Skin biopsies provide a database for investigations of stock structure, phylogenetic relationships, and the reproductive potential of female dolphins. Acoustic recordings supplement visual survey data and provide information for ongoing studies of cetacean vocalizations.

NOAA Fisheries also implemented an observer program in the early 1970s that has collected thousands of biological samples to study ETP stock structure and to quantify life history characteristics of the population. NOAA Fisheries can use information from the assessment surveys and the observer program to improve conservation and management plans for this species.