Tuna sees optimistic rise in numbers as other marine life decline

·4 min read
Tuna sees optimistic rise in numbers as other marine life decline
Tuna sees optimistic rise in numbers as other marine life decline
Tuna sees optimistic rise in numbers as other marine life decline

While several species of tuna are now on a path to recovery, the same can't be said of other marine life including sharks and rays as a result of ineffective population revitalization measures.

This is according to the International Union for Conservation of Nature (IUCN), which updated its Red List of Threatened Species Saturday to highlight the successes in conservation measures of some ocean species whereas others still need improvement.

SEE ALSO: Enormous shark die-off millions of years ago puzzles scientists

In the latest revision, the IUCN outlined the results of a reassessment of the seven most commercially fished tuna species. Four of them showed signs of recovery as a result of countries instituting more sustainable catching quotas while successfully battling illegal fishing.

The Atlantic bluefin tuna (Thunnus thynnus) was shifted from endangered to least concern while the southern bluefin tuna (Thunnus maccoyii) was moved from critically endangered to endangered. The albacore (Thunnus alalunga) and yellowfin tunas (Thunnus albacares) both changed statuses, as well -- from near threatened to least concern.

The IUCN Red List contains 138,374 species, of which, 38,543 face extinction.

Tuna fish
Tuna fish


“[Saturday's] IUCN Red List update is a powerful sign that, despite increasing pressures on our oceans, species can recover if states truly commit to sustainable practices,” said Bruno Oberle, IUCN director general, in a news release.

“States and others now gathered at the IUCN World Conservation Congress in Marseille must seize the opportunity to boost ambition on biodiversity conservation, and work towards binding targets based on sound scientific data. These Red List assessments demonstrate just how closely our lives and livelihoods are intertwined with biodiversity.”


With word of the uptick in numbers of several tuna species, not all of them are on the rebound. Numerous regional tuna stocks are still severely depleted, according to the IUCN.

As an example, the larger eastern population of Atlantic bluefin tuna, located in the Mediterranean Sea, has increased by at least 22 per cent over the last 40 years. However, its smaller, native western Atlantic community, which breeds in the Gulf of Mexico, has dropped by more than half during the same period. The yellowfin tuna, meanwhile, remains overfished in the Indian Ocean.

“These Red List assessments are proof that sustainable fisheries approaches work, with enormous long-term benefits for livelihoods and biodiversity. We need to continue enforcing sustainable fishing quotas and cracking down on illegal fishing,” said Bruce B. Collette, chair of the IUCN's SSC Tuna and Billfish Specialist Group, in the media release.

“Tuna species migrate across thousands of kilometres, so co-ordinating their management globally is also key.”


The revised IUCN Red List also included a detailed reassessment of the global population of shark and ray species, revealing 37 per cent are now threatened with extinction. The group says this statistic shows that effective management measures are "lacking" throughout much of the world's oceans.

According to its list, all shark and ray species facing threats are overfished, with 31 per cent of them further affected by loss and degradation of habitat, while 10 per cent are seeing a decline from climate change.

Great white shark/Sharkdiver68/Wikipedia
Great white shark/Sharkdiver68/Wikipedia


It isn't just marine species that are under pressure or facing threats.

The Komodo dragon, the world’s largest living lizard, has been moved to endangered from vulnerable on the IUCN Red List. Native to Indonesia and only found in the World Heritage-listed Komodo National Park and surrounding Flores, is progressively threatened by climate change impacts. Acceptable habitat for the Komodo dragon may see a reduction by least 30 per cent in the next 45 years.

As well, although the subpopulation in Komodo National Park is considered stable and well protected at the moment, Komodo dragons outside of the protected areas in Flores are also threatened by significant habitat loss because of continued human activities.

Thumbnail courtesy of Videoblocks.

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