U.S. Trade Lawsuit Aims to Protect Earth’s Rarest Marine Dolphin

The rarest marine dolphin on the planet swims in the waters along the West Coast of New Zealand’s North Island. Today, only 30 to 50 critically endangered Māui dolphins are thought to exist.

On Dec. 4, World Wildlife Conservation Day, Earthjustice and Law of the Wild filed suit to protect this dwindling species in the United States Court of International Trade on behalf of the grassroots group Māui and Hector’s Dolphin Defenders.

These local New Zealand advocates are working to raise awareness and spur action to protect these intelligent, social dolphins. The dolphins are being driven to extinction because they are entangled when fishers target commercial seafood species using gillnet and trawl gear: large nets that hang in the water for days or drag through the sea, scooping up everything. Even if fishers free dolphins from the nets before drowning, the marine mammals can suffer serious health impacts.

It’s a heartbreaking situation, but there are legal tools to protect these rare dolphins. Our lawsuit uses one of these tools, seeking enforcement of the U.S. Marine Mammal Protection Act (MMPA), which requires the U.S. government to ban seafood imports from any foreign fishery that excessively harms marine mammals.

Why does the Marine Mammal Protection Act include a trade ban?

The Marine Mammal Protection Act protects and restores marine mammal populations that may be in danger of extinction or depletion because of human activities. While putting in place strong protections for marine mammals here in the United States, the act also includes a provision to ensure that seafood imported from other countries isn’t caught in a way that harms or kills marine mammals elsewhere — at least not more than what the United States would permit.

This provision ensures that the seafood you put on your plate here will not contribute to the depletion or extinction of marine mammals in any part of the world. It also ensures that U.S. commercial fishers don’t face unfair competition in the U.S. market from foreign seafood that was caught using harmful gear or under lower marine mammal protection standards.

How does the trade ban work?

First, fisheries that want to import to the United States are categorized as “exempt” or “export.” Exempt fisheries, because they are not known to (or are likely to) seriously injure or kill marine mammals, can export fish to U.S. markets. Export fisheries, which have more than a remote likelihood of marine mammal bycatch, need to apply for and receive a “Comparability Finding” from the United States government to export their fish or fish products to U.S. markets. The Comparability Finding is a determination that a foreign nation’s marine mammal bycatch program meets U.S. standards.

This trade ban will be fully implemented on January 1, 2026. However, the law provides pathways to evaluate fisheries sooner, if need be. So far, fisheries affecting two species — the Vaquita porpoise in Mexico and the Māui dolphin in New Zealand — have been raised to the government, evaluated, and even vetted through the court systems. As a result of these evaluations there is a ban on imports from fisheries in the Vaquita dolphin habitat in Mexico.

What happened to the first court case to protect the Māui dolphin?

In 2019, Sea Shepherd Conservation Society (in the United States) and Sea Shepherd New Zealand submitted a petition requesting a ban on imports of fish from New Zealand fisheries having an adverse impact on Māui dolphins. This was followed by a lawsuit in the Court of International Trade filed in 2020 — the same court we filed our lawsuit in more recently. In 2022, in response to the Sea Shepherd suit, the Court banned some New Zealand seafood imports to America. In response to the issues raised by the Sea Shepherd organizations and the court, the U.S. government issued a new and revised Comparability Finding in 2024. This Comparability Finding says New Zealand export fisheries in Māui dolphin habitat are comparable to U.S. standards. The Sea Shephard case was then dismissed — not because the court found the latest Comparability Finding was adequate, but because the Sea Shepherd organizations in that case chose not to challenge the 2024 Comparability Finding.

Māui and Hector’s Dolphin Defenders remain concerned because, despite some incremental steps put in place by the New Zealand government to protect Māui dolphins once the 2020 litigation began, the population is still in decline. In fact, since the Sea Shepherd litigation began in 2020, Māui dolphin numbers have continued to decline from 63 (2020) to 43 (2024): a loss of about 30%. After reviewing the law and expert input, we found that the latest Comparability Finding fails to apply U.S. standards, includes several analytical errors, and certifies the fisheries for all marine mammals, not just Māui dolphins, without performing the required analysis. Because of these deficiencies, Māui and Hector’s Dolphin Defenders recently filed suit challenging the latest Comparability Finding.

Why Māui dolphins?

Māui dolphins are critically endangered and it’s clear that Māui dolphins are being excessively harmed. Fifty years ago, there were 2,000 Māui dolphins. Since then, the population has plummeted by over 97%. Over the past two decades, the population has declined by 3 to 4% per year. This would not have happened under the U.S. Marine Mammal Protection Act.

As the lawsuit points out, “Even low levels of human-caused mortality can outpace the population’s natural growth rate, leading to its extinction.”

Māui dolphins are highly intelligent. The species has a complex social system, and they typically live in small, tight-knit groups of two to eight. The loss of a single member of one of these groups can disrupt their social dynamic. Māui dolphins’ biology makes them especially vulnerable to human impacts; they live about 25 years, and females don’t reach sexual maturity until around eight years old and produce just one calf every two to four years.

With such a critically low population, Māui dolphins can’t afford a mistake by the U.S. agencies charged with ensuring that United States actions don’t contribute to the species’ decimation. And that’s why we filed this new lawsuit. The United States should not be importing seafood from countries that aren’t protecting the marine biodiversity that every one of us depends on for a healthy planet.