BBC South Pacific - Series 1 Episode 6 (last episode)

The most successful wildlife documentary of all time was the Blue Planet produced by the BBC perhaps around 2004. It has the most amazing images of yellowfin tuna feeding on bait balls. Watching such documentaries, you could be forgiven for asking: overfishing?, what problem? This dire lack of "we don't tell people what to do, eat/we don't do environment, we just like to show the wilderness" was overturned in the last episode of South Pacific, series 1 episode 6. It is still available at the time of writing on BBC iplayer and I would urge all those in the UK to see it and for others to get a copy of this series of programs. This film gave a devastating portrait of purse seine netting with footage from a ship capturing 150 tonnes of yellowfin tuna along with skipjack. It also showed by way of contrast long line fishing for big eye and the best method of commercial fishing, pole and line skip jack fishing from the Solomon islands.

This episode also showed coral gardening around Fiji to make the fish return, and marine conservation along with ecotourism that helps sustain shark numbers. Benign tiger sharks approach divers to accept food. Magnificient and better than horrid shark fin soup.

Here are some facts from South Pacific, Episode 6 for my own reference as well as for your information, with regards to our favourite fish. Tuna is an industry worth 8 billion dollars (per year?). Over 4 million tonnes of tuna are caught per year with a four fold increase in capture in as many decades. Skipjack tuna are the commonest and have thus far been regarded as a hard fish to dent in terms of its populations, though doubts are now being raised about this. It reaches sexual maturity in 1 year and thus breeds quickly. Typically, adults reach 2kg in weight when caught though left to grow, they could reach 10-20kg reaching 40 inches (1m). Yellowfin is also heavily exploited. They can reach 80+ inches (2m) reaching well over 100kg. They are slower breeders. In the atlantic, yellowfin catches are declining since the 1990s and there is no protection for wild Atlantic yellowfins.

European purse seiners are increasingly targeting this species in particular from the pacific. 2/3rds of all tuna caught now comes from the Pacific. Purse seine nets can be up to 2km long in circumference and 200 m deep. A small purse seiner could catch 100 tonnes of yellowfin and skipjack in 1 go representing over 10,000 individuals (each 2-100kg). In the program they showed a boat targeting a shoal of 150 tonnes. First the shoal is encircled by the net using speedboats. They drop balls of yellow dye and create turbulence in a large circle to encourage the shoal of fish to stick together while they are being herded into the middle. When the net surrounds them, a draw string is pulled to seal the net from below and close the net. Here the divers began filming. We could see, sharks as elements of the bycatch dying on the net or dead and one turtle that was rescued. If it was a large purse seiner, lots of sharks and turtles could get killed (see "what's the cost of a tuna sandwich?" on youtube about bycatch). The yellowfin tuna began to panic. They need to swim fast in order to survive and keep aereated but started bleeding to death while trying to escape from the net or by suffocating. As the ball became smaller, the fish start dying while struggling to escape and if they are left too long, lactic acid produced by panicked fish causes a loss in quality in the meat, so they try to haul them in as fast as possible. The fish are unloaded in baskets 1-2 tonnes at a time into the freezer holds. This 150 tonnes represented a regulated catch from PNG waters. In the open international waters, it is a free for all and 4 times this much, 400+ tonnes of fish can be scooped by the largest purse seiners - a Spanish one was shown from Greenpeace footage. Imagine a net catching 400 tonnes of fish in a single go. According to this episode, it would have taken traditional fishing boats 1 year to catch 150 tonnes of fish.

Purse seining is unselective as to target species with lot of discarded bycatch (this is probably why cans of tuna say "tuna" with no species identified - they don't know). All the age classes of fish are caught from young to old eliminating potential breed stock that is not sexually mature. Finally, they catch too much fish that is now plunging in abundance and it is an unregulated free for all in international waters.

By contrast, pole and line allows you to throw off underaged fish. Some of the targetted shoal can swim off. Relatively fewer fish are caught at the same time. There is no bycatch - and it is as sustainable as tuna get, if regulated as to quota.

I learned by watching this episode that yellowfin are, like so many of their kind, are some of the fastest and most intelligent fish in the sea, so callously regarded as only good for sandwiches in Europe and the States. They provide what would on land be regarded as the most stunning wildlife spectacle imaginable, but at sea, we never get to see them in action except in places like this program. What large purse seiners from foreign countries are doing to the tuna shoals in the Pacific is an unregulated scandal. Never before have humans had the capacity to take out so many fish unselectively in a single scoop. This episode also highlighted shark finning - another story.

I intend to turn the screenshots of the film into a short YouTube video. Watch the Youtube.com/slwildlife space. Finally, avoid poorly labeled tuna like cans of John West tuna that simply say "tuna" with a "dolphin friendly" tag. Instead go for MSc certified pole and line caught albacore (from Sainsbury's) or at least just "pole and line" caught tuna, period. Nothing less should do when it comes to tuna. I intend to boycott line caught and undescribed tuna given that long lines are hardly short at 30-100 miles of baited hooks. Maybe more sustainable than purse seiners but certainly could do better as there is no bycatch reporting or information.