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 — studying humpback whale populations in partnership with CONANP and researchers from UABCS.
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, conducted in close collaboration with CONANP rangers and scientists from UABCS under Dr. Jorge Urban and Dr. Hiram Rosales, 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 recordings 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 the M/V Martin Sheen for weeks of methodical fieldwork in one of the world's most biologically productive ocean environments.
Annual Vessel Expeditions
The M/V Martin Sheen deploys 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 complex songs of male humpbacks — documenting behavioral changes, territorial signals, and cultural transmission patterns year over year.
Pristine vs. Impacted Comparison
Findings from Revillagigedo — pristine, protected — are compared against humpback populations in Los Cabos, where heavy boat traffic shapes a measurably different reality for calves and mothers.
Government & Scientific Partnership
Working alongside CONANP rangers and UABCS researchers under Dr. Jorge Urban and Dr. Hiram Rosales, every Sea Shepherd expedition supports both the whale science program and the park-wide dive surveys that count fish, corals, and invertebrates across the UNESCO World Heritage Site.
These expeditions depend entirely on the support of people who believe science and conservation belong together. Help keep the Martin Sheen on the water.
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