Many Pacific bluefin tuna make epic migrations across the Pacific Ocean, traveling from the Sea of Japan to the U.S. West Coast, and back again. Photo by Richard Herrmann/


International Victory for Pacific Bluefin Tuna

Pacific bluefin tuna are powerful predators, built for endurance and speed. They're also extremely lucrative; the steep price they fetch at fish markets has depleted the population to less than 3 percent of its size before industrial fishing.

Now—thanks in part to the work of our science, policy and sustainable seafood teams—this struggling species may be on the path to recovery. After years of effort by the Aquarium and our allies, Pacific nations meeting in Busan, South Korea reached a breakthrough agreement establishing a long-term management plan for Pacific bluefin tuna. If nations follow through, the agreement will allow the population to rebound to a sustainable level.

"This was a historic moment for this remarkable species, which is so important to the ocean ecosystem and people around the Pacific Rim," says Chief Conservation Officer Margaret Spring.

The Aquarium is a leading voice for the science-based management of Pacific bluefin tuna. We work across sectors and borders—in collaboration with scientists, fishing groups, NGOs and government agencies. Our staff experts have forged strong partnerships withour colleagues in Japan and Mexico, both in the scientific research of the species (see story, below), and as policy advisers in international management negotiations

In advance of the meeting in South Korea, we rallied nearly 200 chefs and culinary leaders worldwide, who called on governments to adopt a meaningful, science-based recovery plan. Former U.S. Secretary of State John Kerry joined us in urging swift international action.

The sustainable management of Pacific bluefin tuna has a long way to go, but the 2017 agreement will help establish a credible, science-based roadmap to recovery. We look forward to collaborating with Pacific nations to implement the agreement, and to advance the critical research and diplomacy that will ensure a more sustainable future for this remarkable species.

Discovering the Secrets of an Epic Ocean Odyssey

Researchers at the Aquarium, together with colleagues from Harvard University and the National Museum of Natural History, have revealed new evidence of how many Pacific bluefin tuna travel across the ocean. The research underscores the importance of bluefin fishing limits, and effective enforcement, on both sides of the Pacific. The Western Pacific is where all Pacific bluefin spawn, and where most of the fish are caught. The eastern Pacific serves as an important nursery area for juvenile bluefin.

Analyzing data from tracking tags, the scientists found that most spawning-age Pacific bluefin have crossed the planet's largest ocean basin twice: leaving their home waters off the coast of Japan at just one to two years old, spending the next four to six years in the rich feeding grounds off the coasts of California and Mexico, and returning to the Western Pacific to spawn.

By catching too many fish in both locations, we end up with a severely depleted population. This study is an example of the rigorous research needed to inform the sustainable international management of Pacific bluefin tuna.

Our tuna research team and their Japanese colleagues deployed over 2,000 tracking tags on young Pacific bluefin tuna near Kochi, Japan Nereus Principal Investigator—Fisheries Dr. Andre Boustany and Senior Scientist Chuck Farwell tag Pacific bluefin tunas off the coast of southern California and northern Baja.

Nereus Principal Investigator–Fisheries Andre Boustany and Senior Scientist Chuck Farwell tag Pacific bluefin tunas off the coast of southern California and northern Baja.

Research to Protect Vulnerable Species

By studying the population biology and ecology of threatened species, we are better positioned to understand the threats they face—and to inform policy and management decisions that support healthy, resilient populations. The Aquarium and our partners are tracking vulnerable wildlife like sea otters, bluefin tunas, sharks and rays in new and more robust ways, contributing to a growing body of knowledge needed for strong, science-based management.

Senior Research Scientist Sal Jorgensen and a colleague celebrate the successful deployment of a white shark tracking tag.

Senior Research Scientist Sal Jorgensen and a colleague celebrate the successful deployment of a white shark tracking tag.

Our research team identified 89 white sharks along California's coast, providing insights into population size, migrations and behavior. This adult white shark at the Farallon Islands was named “Middle Notch” for its distinctive dorsal fin.

This adult white shark at the Farallon Islands was named "Middle Notch" for its distinctive dorsal fin.

Devil rays school in the Pacific Ocean

Tracking the Health of Devil Rays

When yellowfin tuna are caught using purse seine nets, schooling devil rays are frequently hauled in as bycatch—and then released. Our research team took a closer look at the post-release fate of these graceful mobulids, the smaller relatives of manta rays, in the tropical Eastern Pacific.

Owing to their slow reproduction rate and delayed maturity, all mobulid species are listed for protection under an international agreement called the Convetion on International Trade in Endangered Species of Wild Fauna and Flora, or CITES. Under CITES rules, tuna fisheries must release all accidentally caught mobula, following careful handling protocols.

We're collaborating with key partners in Ecuador to learn which species are captured and how they fare post-release, using tools such as genetics testing and electronic tagging.

The cover of Science magazine features a Tuna Research and Conservation Center study.

Discovering Bluefin Tuna "Hydraulics"

Researchers with the Tuna Research and Conservation Center, a partnership between the Aquarium and Stanford University, published a ground-breaking study of tuna physiology in the journal Science. Researchers discovered that Pacific bluefin tuna can manipulate their dorsal fins using their lymphatic system—the first time this complex mechanism, a biological hydraulic system, has been observed in any vertebrate.

California's Sea Otters Bring Coastal Benefits

The Aquarium's Sea Otter Program works to recover southern sea otters and their homes along the California coast. Our team's 30-year commitment to research, rescue and education allowed us to tackle a broad range of sea otter conservation issues in 2017.

A raft of sea otters floats in Monterey Bay.

For the second year in a row, California's sea otter population index has topped 3,090—an encouraging number that indicates conservation efforts, including our Sea Otter Program, are bringing this iconic animal back from near-extinction.

Southern sea otters currently inhabit a 300-mile span of California's central coast, from south of Half Moon Bay to just beyond Point Conception. This represents just a fraction of the waters they occupied before fur traders decimated the species in the 19th century. In order for southern sea otters to truly recover, they must return to their former habitats along California's 1,100-mile coastline—places they haven't inhabited for over 100 years.

We've seen how well coastal ecosystems respond to the presence of sea otters, from the return of thriving kelp beds along the rocky coast to the renewed productivity of wetlands like Elkhorn Slough. Many other areas along the California coast could benefit from sea otters' return.

Sea Otter Program Manager Michelle Staedler and an Aquarium citizen scientist track otters in Elkhorn Slough.

Sea Otter Program Manager Michelle Staedler and an Aquarium citizen scientist track otters in Elkhorn Slough.

Now, researchers are asking whether sea otters can recolonize waters beyond the Central Coast without human intervention. In 2017, Aquarium experts began exploring the potential to reintroduce sea otters to coastal habitats where they could act as ecosystem engineers.

Recovery of California's sea otters has been an Aquarium priority for more than three decades, and we’ve produced a body of scientific data that positions us to lead the complex challenge of sea otter reintroduction. Our team continues to study sea otter populations, to return stranded and orphaned sea otters to the wild, and to support policies that protect the coastal habitats on which they depend.

The Aquarium’s Sea Otter Program rescued its
800th live-stranded sea otter
We observed nearly 9K sea otter foraging dives in a study of predator-prey interactions

Conservation & Science Report 2017 (PDF)

  • Credits
  • © Monterey Bay Aquarium Foundation