Revillagigedo Archipelago · Operation Treasured Islands
North America's Greatest
Whale Nursery
Since 2017, Sea Shepherd has conducted annual scientific expeditions to the Revillagigedo Archipelago, North America's largest marine protected area, documenting humpback whale populations, health, and behavior in one of the Pacific's last truly protected ocean environments.
Operation Treasured Islands — Revillagigedo
M/V Martin Sheen · Socorro Island · February 2020
A Pristine Laboratory for Whale Science
The Revillagigedo Archipelago, four volcanic islands rising from the Pacific 240 miles southwest of Cabo San Lucas, is among the most productive marine ecosystems on Earth. Designated a UNESCO World Heritage Site in 2016 and home to the largest marine protected area in North America, it draws humpback whales each year from late January to late March to breed, give birth, and nurse their young.
Sea Shepherd's expeditions employ four core research methods: visual surveys of whale groups and behavior, photo identification of individuals by fluke and dorsal fin markings, biopsy sampling for genetic and health analysis, and passive acoustic recording of male song patterns.
A parallel study compares humpback calf growth and maternal body mass here, in pristine, protected waters, against populations in Los Cabos, where high human activity shapes a very different environment. The data informs management decisions across Mexican marine protected areas.
Population Dynamics
Long term photo ID catalogues track individual whales returning season after season, measuring survival, fidelity, and reproductive success.
Whale Health Monitoring
Blubber biopsies reveal stress hormones, reproductive status, genetic identity, and accumulation of contaminants in each individual whale.
Acoustic Behavior
Hydrophone recordings capture the song of the season for 30–40 minutes per session. Humpbacks change their song annually, making these a year over year record of behavioral change.
Submarine Ecosystem Monitoring
In parallel with whale research, expert divers count fish species, corals, and invertebrates across the park to evaluate ecosystem health and inform CONANP conservation priorities.
What Our Expeditions Do
Each voyage brings scientists, crew, and conservationists together aboard Sea Shepherd vessels for weeks of methodical fieldwork in one of the world's most biologically productive ocean environments.
Annual Vessel Expeditions
Sea Shepherd vessels deploy to the Archipelago each season, providing a stable research platform and a visible conservation presence in one of Mexico's most remote marine sanctuaries.
Fluke Photo Identification
High resolution photographs of humpback tail flukes allow researchers to identify and track individual whales across seasons, building a living catalogue of the population.
Biopsy Sample Collection
Small skin and blubber samples, retrieved by crossbow dart with no harm to the animal, are preserved in cold and liquid nitrogen for laboratory analysis of genetics, contaminants, and hormones from each individual whale.
Hydrophone Acoustic Recording
Underwater recordings capture the songs of male humpbacks, documenting behavioral changes and song evolution year over year.
Pristine vs. Impacted Comparison
Findings from pristine, protected Revillagigedo are compared against humpback populations in Los Cabos, where heavy boat traffic shapes a measurably different reality for calves and mothers.
Scientific Field Support
Every Sea Shepherd expedition supports active whale science and park-wide dive surveys counting fish, corals, and invertebrates across the UNESCO World Heritage Site, contributing data that informs CONANP conservation decisions.
These expeditions depend entirely on the support of people who believe science and conservation belong together. Help keep the Martin Sheen on the water.
Support the Mission