Once disappeared bluefin tuna was "prized" and now returns to UK waters in the South West

The bluefin tuna was once common to UK shores before it was driven away by overfishing. In recent news, the species has returned to English shores, but for uncertain reasons.

The bluefin tuna has a torpedo-shaped body, as a formidable predator and a source of prey in the ocean, where it migrates widely.
The bluefin tuna has a torpedo-shaped body, as a formidable predator and a source of prey in the ocean, where it migrates widely.

The Atlantic bluefin tuna (Thunnus thynnus) is the largest of the tuna species, with torpedo-shaped bodies. As apex predators, they live in temperate waters near the surface ocean, diving as deep as 1,000 metres. They have a long lifespan, up to 20 years, and are highly migratory, having been found in the Gulf of Mexico to spawn. As sharks and marine mammals feed on them, they have an important place in the marine food web.

This was once a common predator in British seas, but in the 60s they disappeared after being pushed to the brink of extinction in the east Atlantic because of overfishing. In recent years, the numbers of sightings of the Atlantic fish has been increasing from British coasts.

Bluefin tuna pops up in the South West

In positive environmental news, this huge migratory fish has returned, in the thousands, off the coast of Cornwall, and the South West region of England. Currently, a sports fishery and a commercial bluefin tuna fishery is being trialled off the Cornwall coast.

This seems to be a sign that major cuts to fishing quotas in the east Atlantic ocean were a success in reviving them. But these new numbers were unprecedented to experts.

Bluefish tuna is no longer considered an endangered species in British waters. Some photographers delight in catching snaps of it when it hunts closer to the coast. Their sightings can also be enjoyed on local boat trips.

Last year, the first commercial bluefin fishing season was initiated since over 60 years, after a three year trial involving tagging and releasing the fish studied the impacts of sport fishing on the species. The result of the programme is shown in the infographic below.

Result of the CHART tagging initiative of the bluefin tuna species.
Result of the CHART tagging initiative of the bluefin tuna species.

Resurgence in the UK gives hope

Now, a resurgence gives hope to not only the species but the fishing port towns that once harnessed and celebrated it throughout their history, such as Scarborough and fishing ports of Cornwall.

The tag-and-release programme involved 10 boats catching 39 tonnes, which were several hundred fish. The skipper of the town Chris Gill told the Guardian: “When I was younger, you’d occasionally hear of a bluefin being caught by a commercial fleet. Now, they are here in their thousands. Thousands and thousands. We get a good run of anchovies, sardines, mackerel and herring. The tuna are here feeding on them.”

International outlook

Meanwhile, species numbers are also making a comeback in the Mediterranean. Charity WWF declared that bluefin tuna are one of the most important fish present in the Mediterranean, for not only their role in food webs, but for commercial value, where they have supported local communities since ancient times as an important food source.

In the US, numbers of western Atlantic bluefin tuna are unknown, but numbers are sustainably managed under a restricted harvest by the country’s fishermen. In the UK, stocks may be recovering, but fishing will still need to be monitored so that populations are sustained and do not go through undue tension.

The NOAA advised that that international cooperation is needed as well as domestic management for the effective conservation and management of highly migratory species like bluefin tuna. The IUCN recommend to consider environmental conditions in new stock management plans, to maintain populations. Continued success to their conservation in UK waters in the long term may be determined by the union of scientists, local authorities, the government and the public.