Giant predatory fish that had almost vanished from British waters by the 1960s are now showing up off Cornwall in numbers large enough to surprise the scientists tracking them.

  • 73% average decline in global monitored wildlife populations since 1970 (the report's headline warning)
  • 70%+ increase in wild tiger numbers — from roughly 3,200 in 2010 to about 5,700 in 2025
  • ~80 countries involved in the green sea turtle's recovery, now downgraded from "endangered" to "least concern"
  • 36,000 wildlife populations across almost 6,000 species tracked worldwide

How Overfishing Nearly Wiped Them Out

Atlantic bluefin tuna were once common in the waters off Britain. Decades of overfishing — of both the tuna itself and the smaller fish it feeds on — pushed the species to near-disappearance from UK waters by the 1960s.

The turnaround, detailed in WWF's 2026 Living Planet Report, came from a coordinated international push: reduced catch quotas, minimum size limits, and protected spawning grounds, backed by campaigns from chefs, retailers and anglers. Hannah Rudd of the Angling Trust called the result close to an "explosion" in the population.

By 2015, bluefin were being spotted off Penzance. The species was delisted from overfished status five years later, and this past August a pair of 300kg giant bluefin were landed in Yorkshire — the first catch there in more than 70 years.

Other Wins In The Same Report

The tuna's comeback isn't an isolated case. WWF, working with the Zoological Society of London, highlighted several other recoveries in the same report:

Elephant numbers are stable or growing across parts of southern Africa, aided by laws that give local communities a direct share of tourism income. Wild tiger populations have climbed more than 70% since 2010. Nepal's Khata Biological Corridor has been restored, helping local tiger numbers recover further.

"Hope is not the same thing as wishful thinking. Hope is not passive. Hope's about action." — Mike Barrett, chief scientific adviser, WWF-UK

A Closing Window, Not A Closed One

The report isn't a victory lap. Globally, monitored wildlife populations have still fallen by an average of 73% since 1970, and WWF estimates roughly $7.3 trillion flowed into activities that harm nature in 2023, compared with just $220 billion spent protecting it — a 33-to-1 imbalance.

Dr. Katie Collins of the Natural History Museum in London also notes the index tracks only vertebrates, missing the plants and insects those animals depend on. "If you lose garden snails, you lose the song thrush," she said.

Barrett, who has worked on seven Living Planet reports, says this is the first where the central message is hope rather than alarm — not because the crisis has passed, but because the bluefin tuna and the other recoveries prove the tools for reversing decline already exist and work when applied with sustained commitment. "It's a closing window of opportunity," he said, "but it's still open, just, if we act now."

For a fish that was nearly gone from British seas a generation ago, that's a case study worth watching.