“Wild-caught seafood is quite a complex subject and it’s hard to know what’s a good choice,” says Jack Clarke, Seafood Engagement Manager at the Marine Conservation Society. “We developed the Good Fish Guide over 20 years ago to help people cut through the complexity and make it easier to know which fish to serve and eat.” Here are some of the species that need protection most urgently. 

Eel

“European eel is one of the few options that’s an absolute no-go. It’s more endangered than a panda and criminal gangs make over €3 billion each year smuggling it out of Europe,” says Clarke. “Things have got so bad that scientists have issued their sternest advice ever for its continued survival: zero catches, even for restocking, restoration and aquaculture.” 

The sharp decline in eel populations worldwide has been driven by a lethal combination of overfishing, habitat loss, pollution, the damming of rivers and the climate crisis. Stocks of baby eels are estimated to have dropped by 95-99% since 1980. Furthermore, as Clarke mentions, eels are a common target for smugglers; driven by dwindling global populations and high demand (particularly in Asian markets), an estimated 100 tonnes of juvenile eels are smuggled out of the EU each year.  

Around 5,500 tonnes of farmed eel are currently produced across Europe each year to meet this incessant demand. However, little is understood about the eel’s life cycle, meaning that these operations rely entirely on catching juvenile eels in the wild – only exacerbating the problem.  

Eels are on the Red List of Threatened Species managed by the IUCN; European eel is Critically Endangered, while Japanese eel and American eel are both classified as Endangered. Despite there being no sustainable sources of eel left, it’s still a common feature on menus worldwide. “There are some iconic restaurants that still serve eel,” says Clarke. “There are arguments around eating them for their cultural value – but any kind of culture that eats an animal to extinction can’t possibly value it. The one thing we can do to help is to stop eating eels. We need to stop selling them in restaurants.”  

Shark

Shark fin soup is consumed by many communities across Asia and is one of the main drivers of the massive decline in shark populations, estimated at 70%. As many as 80 million sharks are killed annually for shark fin soup alone – and that’s not counting those caught for other commercial uses (to be processed as meat, leather or health supplements) or as accidental bycatch. The ‘finning’ method often employed by those on the hunt for shark fins is a particularly cruel practice, with sharks thrown back into the oceans once their fins have been removed and left to die in agony from suffocation, blood loss or predation. Because they have low rates of reproduction, their populations are hit particularly hard by these practices. 

Up to 30% of the sharks exploited for their fins are from Endangered species, including the Scalloped Hammerhead and Great Hammerhead. In addition to the damage being done to their own populations, sharks are apex predators and play a critical role within marine ecosystems; without them, the entire food chain is affected. In an effort to save these species from extinction, trade is regulated by CITES – but dried fins from these sharks are still being sold. China is the primary market, with around 50% of the dried fin market brokered through Hong Kong. Shark fin is also consumed in the US.  

While shark fin is never an ethical option, Clarke clarifies that not all types of shark are off the table. “There are hundreds of species of sharks. While we wouldn’t recommend you eat most of them, there are a handful of sustainable fisheries for sharks out there – and where there are well-managed sources of seafood, we should support them. Look out for MSC-certified spurdog from the USA. For all other sharks and rays, check the Good Fish Guide.”  

Bluefin Tuna

Bluefin tuna is one of the most commercially valuable fish on the planet, and as a result there are ongoing problems with overfishing across the world. All three species of bluefin — Atlantic, Pacific and Southern — have been heavily overfished. Because tuna are migratory and swim thousands of miles across the ocean each year, international regulation is particularly difficult. Tuna is also slow to come to maturity, making it more challenging for stocks to recover. 

Pacific bluefin tuna is listed by Marine Conservation Society as a Fish to Avoid. Heavily overfished in the past thanks to an extremely high market value, the species remains at very low levels. Similarly, Southern bluefin tuna – an extremely valuable fish popular for use in sushi and sashimi – was very nearly fished into extinction in the mid-90s, leading to the global listing of the species as Critically Endangered. Southern bluefin was recategorised as Endangered in 2021, reflecting a small degree of recovery, but this is another fish for which there is currently no sustainable source. 

“I am concerned about the future of bluefin tuna. With sushi gaining worldwide popularity, the demand for tuna is increasing globally,” says Yuuki Tanaka of Ise Sueyoshi, a kaiseki restaurant in Tokyo. “Despite being an endangered species, the ongoing demand means that even if the population decreases and prices rise, there will still be people willing to buy it. Without regulations to impose limits, this situation could essentially mean a countdown toward extinction.” 

There have been tentative signs of increased numbers of Atlantic bluefin tuna in recent years, although there are still no ‘Best Choice’ sources listed by Marine Conservation Society. While this recovery is in the very early stages and demands that we proceed with caution, Clarke points to the story of Atlantic bluefin as proof that we can make real change. “People all over the world worked together for this. They took bluefin off menus. They sat down at boring meetings and agreed to develop rules and stick to them. Now, we’re seeing bluefin tuna along coasts again. People [in the UK] pay good money to catch, tag and release them, and we can land limited numbers to eat and enjoy. That’s cultural value.” 

Kyle Connaughton of SingleThread Farms gives us an insight into the bluefin situation in Northern California. “While the fishing of wild bluefin tuna is incredibly problematic, there are several efforts to raise bluefin in a ranched operations that are also restocking wild populations. In certain cases, there is an opportunity to create economic viability for fisheries that are working to reverse the issues with wild stocks; we must, however, watch their work closely.” 

Wild-Caught Caviar

As MCS notes in the Good Fish Guide, the value of wild sturgeon caviar is so high that there is a substantial illegal fishing trade, putting these fish in critical danger. In fact, WWF describes sturgeons as the most endangered species group on earth, on the brink of extinction due to habitat loss and overfishing driven by the rampant demand for caviar. “Sturgeons are economically and culturally important in every river basin and country across their traditional range. We are aiming to rebuild their populations by tackling the illegal caviar trade and enhancing the health of river systems.” 

Farmed caviar is the only viable choice, as numbers of wild-caught sturgeon are dangerously low. Farmed sturgeon bred in hatcheries, so there is no dependence on wild fish for broodstock. It is worth noting that farming sturgeon is still an inefficient use of resources, as it relies on a high intake of fish meal and oil per gram of protein produced; this comes with its own sustainability problems.  

Local Concerns

Connaughton says, “The above are some of the worst examples on a global scale, but it’s also important to consider what’s happening on a local level. In California, we’ve seen a complete depletion of wild abalone due to overfishing and collecting.” He explains the knock-on effect that this has had on the local ecosystem. “It’s led to sea urchins moving into the habitat and destroying the kelp beds. These beds are the home to the otter, the natural predator of the sea urchins.” With the otters displaced, sea urchin populations continue to rise. “While abalone farms are restocking the wild populations, it takes time and effort by them, sea urchin divers and many other people to reverse the multiple issues that have occurred due to the overfishing of one species.”  

“It’s very specific to location and even a certain year,” Connaughton continues. “For example, we’re watching local salmon and Dungeness crab very closely, year by year, to really understand what our impact may be. I’m particularly concerned with the future of King crab in Alaska and Hokkaido; that’s something we all need to watch closely.” 

In Taiwan, Captain Huang Shih-Yang from Daxi Fishing Harbour is a key figure in local marine sustainability efforts. As a leader of the Marine Waste Fleet, Captain Huang has witnessed firsthand the detrimental effects of modern fishing practices, ocean pollution and the climate crisis. He tells us that traditional species once common in Taiwan – such as red seabream, mackerel and mullet – are becoming increasingly rare. 

Other Popular Fish

While they might not (yet) be listed as endangered, it’s important to remember that plenty of the most popular fish are in a constant battle to survive. “I think most people know about things like shark fin and tuna, but a lot of the wild-caught popular fish are really struggling,” says Graham Long, Executive Chef at Hong Kong’s EAST Hotel. “Atlantic cod has been an issue for a long time, and slow-growing species like Atlantic halibut take a long time to replace in the ecosystem.” 

Clarke points to the necessity of maintaining complete, up-to-date visibility in your supply chain. “Wild Atlantic halibut is a Critically Endangered animal. It’s red-rated on the Good Fish Guide and should not be eaten. However, farmed Atlantic halibut is an ocean-friendly, green-rated option in the Guide. It’s really important that you know what you’re buying, and where and how it was caught or farmed.” 

The climate crisis poses its own concurrent problems. Many Northern fish species are struggling to handle the warming waters, which are increasing the risk of parasites and disease. Fewer fish are surviving into adulthood, and many of the fish caught are juvenile and may not yet have reproduced – meaning fewer fish in the following generation. 

This is true of shellfish and crustaceans, too. “They’re suffering not just from overfishing but also pollution and habitat loss,” Long continues. “It’s so important that we do our homework on where stocks are coming from. There has been some good work helping wild stocks and habitats recover, but there is a lot more still to be done.”