After being fished to the edge of extinction, the IUCN have reported that tuna numbers are bouncing back following years of conservation and sustainable fishing efforts through reduced catch quotas, outlawed fishing methods and clamping down on illegal fishing. The latest update revealed encouraging signs for four of seven tuna species:
A word of caution in the excitement however. The IUCN reports that despite global improvement at the species level, many regional tuna stocks remain severely depleted. For example, while the larger, eastern population of Atlantic bluefin tuna, which originates in the Mediterranean, has increased by at least 22% over the last four decades, the species’ smaller native western Atlantic population, which spawns in the Gulf of Mexico, has declined by more than half in the same period. The yellowfin tuna meanwhile continues to be overfished in the Indian Ocean.
When buying fresh tuna, the seller will always know both the kind of tuna you are being sold and if it is legal (!). If you buy canned tuna, the kind of tuna has to be listed by law and generally the way it was caught is also displayed on the can. (If it isn't, move to the next can.) Canned Albacore tuna, which is widely on supermarket shelves - is of least concern now.
“I THINK THE GOOD NEWS IS THAT SUSTAINABLE FISHERIES ARE POSSIBLE,” SAYS BETH POLIDORO, A MARINE BIOLOGIST AT ARIZONA STATE UNIVERSITY. “WE CAN EAT FISH SUSTAINABLY AND WITHOUT DEPLETING THE POPULATION TO THE POINT WHERE IT IS ON THE ROAD TO COLLAPSE OR EXTINCTION.”
National Geographic reports that while most people think of tuna only as a potential dinner, these fish are massive, marvellous creatures in their own right. For instance, an Atlantic bluefin tuna begins its life as an egg no larger than the thickness of a credit card. But within a decade, it can grow to lengths of more than six feet and weights of more than 550 pounds. Tuna are fierce predators that zip through the ocean at speeds approaching 40 miles per hour, and they swallow their prey whole - whatever fits inside their gullet.
Populations of sharks and rays are not so fortunate and are continuing to plummet. When the group was assessed in 2014, around a third were deemed threatened, but this has now risen to 37%, due to pressures from fishing for meat and fins, climate change and pollution.
The IUCN Red List of Threatened Species tracks animal and plant species that are close to dying out. Around 139,000 species have been assessed over the last half-century, and of them, nearly 39,000 are threatened with extinction and 902 are extinct.
Images: Unsplash | Kate Bray / National Geographic / Unsplash | David Clode