Gibraltar Chronicle Logo
Opinion & Analysis

The Science - Atlantic Bluefin Tuna No Longer Endangered in BGTW


As the Government recently announced, the local tuna season this year runs from Tuesday 16th of June until Wednesday 14th of October. Some readers may remember the debate last year that occurred in this paper between myself and others surrounding the scientific evidence behind the fishing of Atlantic Bluefin Tuna (ABT).

Given that the tuna season is now upon us, I would like to take this opportunity to inform readers of new evidence which has surfaced over the last year and which unequivocally proves that ABT’s status is improving and that they are no longer endangered in our waters.

International Union for the Conservation of Nature (IUCN)

Last year, when discussing ABT, the Gibraltar Ornithological and Natural History Society (GONHS) noted that the IUCN “is a globally recognised authority on these matters” (GONHS Press Release 09/08/19). Additionally, they quoted the IUCN’s Mediterranean study which at the time listed ABT as being “endangered”.

Over the winter of 2019/20 I therefore set out to gather as much scientific evidence as possible to inform my position on the fishing of ABT. I conducted this exercise in a purely open-minded manner accepting that if the evidence conclusively indicated that ABT were being overfished or were endangered in Gibraltarian waters, then I would have to accept that fishing should be curbed.

I began by reaching out to the IUCN with several questions including whether ABT were endangered in our waters and whether the Mediterranean study which GONHS produced was still valid. I subsequently developed a line of correspondence with the IUCN and on the 16th of December 2019, the IUCN confirmed to me that their Mediterranean study would be changed on their website to demonstrate that it was outdated (IUCN Red List, ThunnusThynnus Mediterranean “needs updating”). Moreover, they confirmed that the most up to date European study was conducted in 2015 and that it removed ABT from the endangered list and vulnerable categories and instead listed it as only being “near threatened” (IUCN European Red List of Marine Fishes 2015).

This news now means that the most up to date study for ABT in BGTW lists the species as being completely outside of the vulnerable categories and one stage away from being classified as “least concern”.

Moreover, although globally ABT remain classified as endangered, this status is almost 10 years old and is set to be changed by the end of this year. Crucially, the IUCN itself encourages legislation to be made based on their regional red lists which “provide information at an appropriate scale for international treaties and legislation” (IUCN Regional List Assessments Webpage). The scientific body even warns against using their global red list, as it can “result in incorrect or even misleading assessments” (Ibid).

Given that, as GONHS highlighted last year, the IUCN is the globally recognised authority on ABT, should we not welcome the fact that ABT have been reclassified in our waters and removed from being endangered in European waters?

ABT Numbers Have Been Improving

Last year we were also told by GONHS that there was no evidence that the numbers of ABT have been increasing and that “until new data become available, the precautionary principle must be adhered to” (GONHS Press Release supra).

Following on from the aforementioned research I conducted, I can also confirm that new scientific evidence also unequivocally proves that ABT stocks are on the rise. Not only does the IUCN’s Pia Bucella note that “Atlantic Bluefin Tuna…stocks have improved” (IUCN European Red List of Marine Fishes, iv), even their own website notes that “overfishing is no longer occurring” and that the current assessment will lead to ABT becoming of “least concern” (IUCN Thunnus Thynnus European Study, 2015).

Moreover, when I contacted the IUCN, they directed me towards the International Seafood Sustainability Foundation (ISSF) which conducts periodic stock assessments. The latest 2020 report asserts that fishing mortality is healthy, that misreported catches have diminished considerably and that the stock of ABT is increasing (ISSF 2020-12: Status of World Fisheries for Tuna). Furthermore, even the article which GONHS themselves used last year (Faillettaz et al 2019) notes that “the stock has started to recover recently”.

It is therefore once again clear that not only is the species no longer endangered in our waters, there is also an overwhelming and growing body of scientific literature which proves that bluefin tuna are well and truly growing in number every year.

Local Evidence

As I noted in my opinion piece last year, locals are increasingly witnessing ABT in our waters. This past spring alone boat owners will recount witnessing huge feeding frenzies (‘comezones’) involving hundreds of tunas in our waters.

Local anglers who fish other species such as mackerel, needlefish, squid and other fish have also seen a dramatic decline in the numbers of these species. As an apex predator which can consume almost a third of its body weight a day, ABT have been rampaging through our waters decimating the other species which reside in BGTW. Personally, I spoke to two anglers who said that this year was their worst year on record in terms of catching squid and mackerel.

Humans are undoubtably a pivotal part of any food chain and without fishing for ABT as our ancestors have done for millennia (see the evidence of the Romans fishing for tuna in Tarifa), we run the risk of allowing ABT to wipe out other species which live in our waters. In Spain, many have already begun calling ABT ‘la plaga’ or ‘the plague’ and given the evidence, it is not hard to see why this is the case.

The Next Steps

Given the above evidence, I would ask GONHS to rethink and retract their stance which was expressed in reaction to the new fishing regulations which they hope will “help limit landings and conserve the species going forward”.

As an NGO and independent body which formulates policy based on scientific evidence, GONHS has a duty to fight for other species which are now endangered in our waters. Several years ago, especially during the early 2000s when ABT was endangered in our waters, I would have wholeheartedly supported GONHS’s campaign against tuna fishing. However, now that ABT are no longer endangered, it is high time for the focus to be shifted to other species which we hear nothing about including vulnerable species like Dentex and critically endangered grouper species (IUCN Red List). Moreover, these endangered species may have their situation worsened if GONHS continues to resist the fishing of ABT which is infamous for consuming almost any and every marine species which it can find.

Additionally, I have long supported a year-round tag and release programme for ABT which would allow anglers to catch ABT all year, take scientific measurements and recordings of the tunas caught, release them safely back into the water and report those findings to the department of the environment. This would prove to be an invaluable exercise which would further the scientific records which we have on this majestic species.

In conclusion, the scientific evidence is clear, unequivocal and growing; ABT are no longer endangered, threatened or even vulnerable in BGTW. With this new information now firmly placed in the public domain, will GONHS change their stance and begin to support local tuna fishermen, or will they contradict their own press release from last year and choose to turn the other way?

Samuel Marrache – Local Tuna Angler

Most Read

Download The App On The iOS Store