EA - Atlantic bluefin tuna are being domesticated: what are the welfare implications? by Amber Dawn

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Welcome to The Nonlinear Library, where we use Text-to-Speech software to convert the best writing from the Rationalist and EA communities into audio. This is: Atlantic bluefin tuna are being domesticated: what are the welfare implications?, published by Amber Dawn on November 7, 2023 on The Effective Altruism Forum.Atlantic bluefin tuna (ABFT) are large, carnivorous ocean fish. They used to be caught relatively rarely, mainly by sports fishermen in North America. However, around the 1950s, Japanese consumers of sushi developed more of a taste for the fish, and a large aquaculture industry developed.Historically, ABFT have been either caught directly from the ocean, or captured while young and fattened in 'ranches'. However, both wild fishing and ranching pose sustainability issues, since they involve taking fish from the wild. Since 2001, there have been a number of EU-funded projects to domesticate bluefin tuna, i.e. to breed them in captivity.This is already done with other types of fish, for example salmon and tilapia, which are raised on fish farms. But it's more difficult with ABFT: they generally don't spawn in captivity, as they require certain specific conditions to spawn.However, scientists have developed methods to make ABFT spawn in captivity, through manipulating light and releasing hormones into the water to stimulate egg production in the fish. This means that it's now possible to farm these fish through 'closed-cycle aquaculture': that is, we can breed them in captivity so that they don't need to be fished from the wild.This has been seen as a win for sustainability. But what about welfare? In this report, I first offer some background on ABFT. I then examine some potential welfare issues in ABFT aquaculture.Main takeaways:Many larvae (young fish) in hatchery projects die. However, this is also true in the wild, and hatcheries may become better at preventing some of these deaths in future, in order to be commercially viable.Many of the conditions in hatcheries might pose welfare issues for ABFT, but more research is needed.The main method of slaughtering large ABFT seems relatively humane; however, the main method of slaughtering smaller ABFT seems more distressing. It's unclear how many ABFT are slaughtered using this crueller method.What are Atlantic bluefin tuna?Atlantic bluefin tuna (thunnus thynnus) are native to the Atlantic Ocean and Mediterranean Sea. They are very large fish: fully mature adults are 2-2.5 m (6.6-8.2 ft) long on average and weigh around 225-250 kg (496-551 lb). Atlantic bluefin tuna (ABFT) have been called 'tigers of the sea' because of their size, grace, and the fact that they're carnivorous predators.In their natural habitat, ABFT can navigate over thousands of miles of ocean. They can dive to depths of 1000m. They eat smaller fish and other sea creatures, generally hunting in schools.Traditional aquaculture of ABFT involves 'ranching'. Juveniles are caught in nets when they gather to spawn, and fed and fattened in large offshore cages. When they are matured, they're slaughtered and sold for high prices.Domesticating ABFTHowever, ranching is not sustainable, since it involves removing ABFT from the wild. Although the International Commission for the Conservation of Atlantic Tunas (ICCAT) regulates tuna fishing by setting quotas, in 2009 their scientific advisors reported that ABFT stocks were probably less than 15% their original size.[1]Therefore, starting in 2001, there have been several EU-funded projects to develop 'closed-cycle' aquaculture for ABFT: the ability to breed them in captivity. DOTT ('Domestication of Thunnus thynnus') was the first such project in 2001-2; this was followed by REPRODOTT (2003-2005), SELFDOTT (2008-2011), and TRANSDOTT (2012-2014).[2]Since then, various entities have set up ABFT hatcheries across Europe, including both public research centres and private companies. More recently, in July 2023, researchers at the Spanish Instit...