The Fish is naked - Tuna Fisheries compared

Tuna - almost like swimming gold and close to extinction. Since the beginning of industrial fisheries about 90% of tuna was caught already (c) Paul Hilton

Tuna became an every day kind of food in recent years, making it hard to see in what bad a state the stocks are by now. Plus: Tuna is hardly ever caught just by itself. The amount of "by catch" - unwanted fish and other animals is alarming!

Purse saine Fisheries in Asia (c) Paul Hilton

The classic way of catching Tuna was done with so called Purse-saine nets. Those are huge nets put around a school of Tuna in round shape and closed from the bottom. The ways of finding the tuna in the first place are wide spread, following other species (like dolphins, which are sometimes easier to spot because of jumping) up to more sophisticated tools like Helicopters or even spotting planes.
Because of the High rates of unwanted by catch in this kind of fisheries the consumers were not always quite satisfied with this way of catching there food. More and more the pressure built to come up with a different way of catching tuna without threatening other animals like dolphins, turtles and sharks.

Longliners are catching big amounts of unwanted by 

catch in ares like the indian Ocean or the pacific areas. Sometimes

 sharks are specifically targeted though and their fins sold

 for a lot of money... (c) Manuel Marinelli/Project Manaia

The next evolutional step of Tuna fisheries are longlines - which basically is exactly what it sounds like: A very long fishing line which is up to 200 miles in length, about 380 Kilometers. Along the entire main line there are small lines with hooks every 10-20 meters (30-60ft). Every single one of those hooks already has a piece of fish/squid on it, an amazing amount of wild caught fish just needed to attract the bigger predators in the process. The pressure building on wild fish just through long lines is amazing: If all the longlines around the world were added up it could be wrapped around the world about 500 times!
Just like Purse seine fisheries, the long line is far from being a sustainable way of fishing as well: The animals being caught as "by catch" include Marlins, sharks, turtles but also dolphins. Just thinking about the fact that 90% of all Tuna have been caught since the beginning of industrial fisheries it should be in everybody's interest to not make stock collapse completely!
The other big problem of those two ways of fishing is: Tuna is one of the fastest fish in the Ocean: To be able to do that they are able to heat up their bodies above the surrounding water temperature to increase the performance of the muscles. The same thing is happening if the animals are exposed to big amounts of stress - the tuna is basically cooking itself from the inside - massively decreasing the value of the meat.

Tuna cages at the coast of Sicily. The animals are fed all 

summer and sold for much more money in fall

(c) Manuel Marinelli/Project Manaia

That's why - particularly when it comes to Bluefin Tuna (the one known for its dark red colour and very popular on Sushi) - Stress should be avoided as much as possible when catching those animals. The beginning of this method is the same as with the common purse seine net. Only this time the net is not hauled out of the water but the net is just kept open for an uncertain amount of time. Depending on where the catch was made it might take up to a few days to get a cage in place and the tuna is transferred into big round cages (around 50 meters in diameter) and pulled to shore. There they are fed with protein enriched food for the rest of the summer and in fall they are killed with harpoons - a quick death making it impossible for too much stress to build up. This way the best price can be asked for the meat - but not too much longer, bluefin tuna is close to extinction already! And every coming catching season in the Mediterranean could be the last one already.

Pole and Line fisheries - extremely effective and yet free
of by catch (c) Paul Hilton

The good news is: There are always good news as well. Looking at the Maldives a lot is moving: "Pole and Line" fisheries got a new push there and is now a rather sustainable way of catching tuna. The targeted species still is one, that doesn't have the healthiest stock ever, but at least there is no by catch at all. The fishermen are literally catching the animals with a pole and a line. At night tiny fish are caught inside the lagoon with nets - those are used to attract the Tuna the next day. On the hunt for Tuna the fishermen are standing on the stern of the boat with a spray of salt water at the stern as well, looking like a big group of small fish from underneath. In addition some of the small fish is thrown into the water as well. The men on the stern actually really only put the hook into the water and pull out tuna - 100% free of integrated species.

The decision whether or not to eat tuna is up to everyone himself/herself again, but everyone should be aware what the consequences of their decision is - not only for the environment, also for themselves:

The big difference between animals on land and in the water is the length of the food chains. A normal food chain on land would consist of 2-3 stages: grass is using nutrients from the ground and gets eaten by a cow, which again ends up on our plates. So there is two stages in that chain for potential heavy metals to collect.

Under water it is a whole different story: Phytoplankton (plant plankton) is getting the nutrients out of the water it is floating in and gets eaten by Zooplankton, which again will be eating by small fish. Those are eaten by medium sized predators, which again get eaten by top predators like shark, Tuna and dolphin. So we are already up on 5 stages in the food chain right there, so the same amount of meat could hold up to 1000 times more heavy metals, pesticides and antibiotics (and anything else that can accumulate in our environments) than for example cow - meat.

The further down in the food chain we pick our food, the healthier it ends up being for ourselves - no matter if in fish, meat or vegetables.

And even though the trend of fisheries is not exactly comforting there are several Organisations out there pushing into a right direction like Project Manaia, The Terra Mar Project, Greenpeace, WWF and many more.

In the end though it is up to every single one of us - the consumer - to make the difference and to act by our believes - every single one counts!