🦭 Picture this: 3,000 massive sea mammals, some weighing over a ton, crammed onto an island smaller than a soccer field.
Every winter, Benten Island—floating just 1.4 km off Japan's northernmost point—is completely taken over by creatures locals call "sea gangsters." They cause $65 million in annual fishery damage, yet internationally, they're protected as an endangered species. This is the front line of one of the most challenging wildlife-human conflicts in the Pacific.
Meet the Steller Sea Lion: The Ocean's Largest Eared Seal
The Steller sea lion (Eumetopias jubatus) is the world's largest member of the eared seal family. Adult males can reach 3.3 meters in length and weigh up to 1,120 kilograms—roughly the weight of a small car. Females are somewhat smaller but still impressive at 2.9 meters and 350 kilograms.
Their range spans the entire North Pacific, from Hokkaido, Japan, to central California. However, all breeding takes place in Russian waters. The sea lions that visit Japan come not to breed, but to overwinter and feed in the rich fishing grounds off Hokkaido.
These powerful predators feast on a variety of fish—rockfish, smelt, walleye pollock, flounder, and rockfish—as well as squid and octopus. Underwater, they're remarkably agile, diving to average depths of 50 meters and traveling up to 20 kilometers during feeding expeditions.
Benten Island: A Sea Lion Paradise
Benten Island sits approximately 1.4 kilometers west of Cape Soya in Wakkanai City, Hokkaido. At just 4,800 square meters, it's slightly smaller than a regulation soccer pitch.
Yet this tiny rock becomes home to thousands of sea lions every year. From November through June, massive numbers migrate south from the Sea of Okhotsk near Sakhalin. Since 2016, their numbers have surged dramatically, with over 6,000 individuals observed at peak times in spring.
In January 2025, researchers counted approximately 3,000 sea lions on and around the island—a record high for that time of year. The animals use Benten Island as a rest stop, launching feeding forays into Hokkaido's coastal waters.
Research by the Hokkaido Research Organization has revealed that Benten Island hosts sea lions from all ten major breeding rookeries along the Asian coast. Approximately 60% originate from Tuleny Island (also known as Robben Island) off Sakhalin's east coast.
Why They're Called "Sea Gangsters"
The nickname "sea gangsters" (海のギャング) stems from the devastating impact these animals have on local fisheries. They infiltrate fishing nets to devour the catch, and frequently tear through the nets themselves, causing extensive damage.
According to Hokkaido Government data, fishery damage from Steller sea lions reached approximately 1 billion yen (roughly $65 million) in fiscal year 2024. This marks a significant increase from about 550 million yen in 2020. The worst year on record was 2013, when damages peaked at nearly 2 billion yen.
Direct damage—torn fishing gear—accounts for about 500 million yen annually. Indirect damage from eaten catches adds another 1.4 billion yen. However, these figures don't account for fish swallowed whole (leaving no trace) or income lost when fishermen voluntarily stop operating to avoid encounters with the animals.
The worst damage occurs between January and March along the Sea of Japan coast, where fishermen target herring and flatfish using gillnets. Sea lions are intelligent and quick to learn which boats catch the most fish, making them persistent and challenging adversaries. Local fishermen say their decade-long battle of wits against the sea lions has been "a complete loss."
Caught Between Endangered Species and Agricultural Pest
The complexity of this issue lies in the sea lion's dual status: internationally protected endangered species versus locally reviled agricultural pest.
On the IUCN Red List, the Asian population of Steller sea lions is classified as "Endangered." Numbers dropped dramatically from about 20,000 in the 1960s to roughly 13,000 by the 1990s. Consequently, both the United States and Russia maintain strict protection measures.
Japan's approach has swung dramatically over the decades. Through the 1960s, sea lions were actively culled as pest animals. In an era difficult to imagine today, Japan Self-Defense Force F-86 fighter jets strafed sea lion colonies, and ground troops used heavy machine guns for "pest control."
International criticism led to reduced culling, but mounting fishery damage prompted another policy reversal. In 2014, the Fisheries Agency established the "Steller Sea Lion Management Basic Policy," aiming to "minimize fishery damage within a range that doesn't risk extinction."
The current annual hunting quota is set at approximately 500 animals. However, actually achieving this number proves extremely difficult due to the aging of specialized hunters and the challenging conditions—shooting from unstable boats in rough winter seas.
The Search for Solutions
Fishing communities and local governments continue experimenting with damage reduction strategies.
Reinforced gillnets offer one promising approach. Made from stronger materials and designed to resist tearing, these nets are harder for sea lions to penetrate. However, their high cost has slowed widespread adoption.
Deterrent measures using blank cartridges (fireworks) and shotgun pellets are also employed, but the intelligent sea lions quickly habituate to these threats.
Training programs for fisherman-hunters have expanded, including subsidies for gun licenses and equipment, plus training courses for novice hunters.
Communities are also exploring ways to utilize culled sea lions. Local businesses produce canned sea lion meat and retort-pouch curry as regional souvenirs. However, demand remains limited—of approximately 250 animals culled annually, only 50-60 are processed for consumption.
A Universal Challenge: Wildlife-Human Coexistence
Benten Island's sea lions also represent untapped tourism potential. On clear days, visitors can spot the animals from Cape Soya with the naked eye, and drone footage of the massive gatherings is genuinely spectacular. Few places in the world offer such accessible views of wild Steller sea lions.
Yet for fishing families whose livelihoods are threatened, simplistic "ecotourism" proposals often meet resistance.
This situation reflects a universal challenge seen worldwide: the collision between wildlife and human communities. Japan alone faces similar conflicts with deer and wild boar damaging agriculture, bears encroaching on residential areas, and invasive species disrupting ecosystems.
How do we protect endangered species while safeguarding the livelihoods of local residents? This difficult question remains without easy answers.
In Japan, Steller sea lions occupy an uneasy position between "pest" and "protected species." How does your country handle the relationship between wildlife and human communities? What are your thoughts on balancing fishery or agricultural damage prevention with wildlife conservation? We'd love to hear your perspectives.
References
- https://www.khb-tv.co.jp/news/16322566
- https://sitakke.jp/post/13639/
- https://wakkanaipress.com/2025/01/08/74707/
- https://www.jfa.maff.go.jp/j/sigen/todohigaitaisaku.html
- https://en.wikipedia.org/wiki/Steller_sea_lion
- https://bioone.org/journals/mammal-study/volume-47/issue-2/ms2020-0029/Origin-and-Abundance-of-Steller-Sea-Lions-Eumetopias-jubatus-in/10.3106/ms2020-0029.full
- https://www.fisheries.noaa.gov/species/steller-sea-lion
Reactions in Japan
Every year this season makes me depressed. Pull up the net and it's torn apart, completely empty. Repair costs alone run into hundreds of thousands of yen. I understand conservation, but please think about our livelihoods too.
Saw the footage of sea lions on Benten Island. What incredible power. If properly promoted as a tourist attraction, this could become Wakkanai's signature draw.
How is it that only Japan treats them as pests when they're internationally endangered? We should seriously explore coexistence rather than culling.
Has anyone tried sea lion curry? Bought it as a Hokkaido souvenir but it had a unique taste. Definitely an acquired preference.
There's a theory that sea lions increasingly rely on nets because overfishing reduced their natural prey. Humans might share some responsibility.
Watched the sea lion colony through binoculars from Cape Soya! The sight of them packed together was breathtaking. Deserves more recognition as a new winter attraction in Hokkaido.
1 billion yen in annual damage... Is there proper government compensation? It's wrong to burden only the fishermen.
Was surprised to hear F-86s used to shoot sea lions. Absolutely unthinkable today. Times have really changed.
Honestly, as a Wakkanai local, sea lions on Benten Island are just normal scenery now. But tourists find it fascinating.
"Sea gangsters" is a cool nickname. But for those actually suffering the damage, it's no laughing matter.
The drone footage was incredibly powerful. Would love to see NHK's Darwin's Amazing Animals do a special on this.
I think there's latent demand for seal and sea lion watching tours. Diving tours in Shakotan are already popular.
Heard the culling hunters are aging, but can't blame young people for not wanting this job... Shooting from boats in freezing seas is brutal.
Benten Island is a precious site where sea lions from all 10 Russian breeding grounds gather. Academically, it's become an extremely important observation point.
In the end, isn't this payback for humans overfishing? Sea lions are just desperately trying to survive too.
We have sea lions at our aquarium too, and they're genuinely intelligent animals. That's why it becomes an endless game of cat and mouse with fishermen.
Being able to see this much wildlife near the Russian border makes it a geopolitically fascinating location.
Over here we're troubled by deer and foxes destroying our pastures. Coexisting with wildlife is really tough.
We face the same issue in Alaska. Steller sea lions are protected as endangered, but fishermen suffer losses. NOAA has strict regulations so we can't actively cull like Japan does. I think compensation systems are needed.
In Poland, we have conflicts between wolves and sheep farmers. Balancing wildlife protection with local livelihoods is challenging everywhere. Japan's case is informative.
Steller sea lions are protected in British Columbia, Canada too. We invest in non-lethal measures like reinforced nets and acoustic deterrents for coexistence with fisheries. Might be more effective than culling.
Didn't know Sakhalin was the breeding ground for these sea lions. Shouldn't both countries cooperate on protection and management? Transboundary wildlife issues can't be solved by one nation alone.
In Sweden, seal damage to salmon farms is problematic. Culling permits are sometimes issued but environmental groups strongly oppose it. Seems Japan faces the same dilemma.
We also have South American sea lion damage in Chilean Patagonia. Some try ecotourism for coexistence, but compensation for fishermen isn't enough. Systems to return tourism revenue to locals are important.
Japanese living in the US here. The Marine Mammal Protection Act strictly protects all marine mammals including sea lions. Japan's culling policy might be hard to understand here. I feel the cultural difference.
Germany has solid compensation systems for wildlife damage. Government fully compensates livestock losses from wolves. Wouldn't similar systems in Japan ease tensions between fishermen and conservationists?
Australian here. Kangaroo population management is debated here. Conflict between conservationists and farmers is a global issue. Ultimately, management based on scientific data is needed.
In Korea, the Japanese sea lion went extinct. While protecting Steller sea lions is important, without supporting fishermen simultaneously, we risk repeating the same mistakes.
From a Norwegian fishing family. Seal damage is serious in the Arctic too, but we manage through combining with tourism. Wouldn't experiential tourism like seafood safaris work in Japan?
California piers are full of sea lions too. Fishermen initially hated it, but now they're tourist attractions. Takes time, but changing perspectives might be important.
In Italy, we work to protect Mediterranean monk seals. International cooperation is essential to save endangered species. Couldn't Japan and Russia achieve more effective management by working together?
Fishery-wildlife conflicts exist along China's coast too. Japan's sea lion issue is an interesting case of balancing economic development with environmental protection. Asia should share knowledge.
Seal tourism thrives in Ireland. By reframing wildlife from 'pests' to 'resources,' conservation and economy can coexist. Perhaps Japan could try a mindset shift?
New Zealand incorporates Māori perspectives into wildlife management. Japan has Ainu wisdom too. Couldn't traditional coexistence knowledge be utilized?