18/09/2015 5:47 AM AEST | Updated 15/07/2016 12:51 PM AEST

There's Something Fishy About The Tuna You're Eating

If you knew the popular canned tuna you were eating might have been caught in slave-like conditions and was potentially contaminated, would you still want it? Would you give it to your kids?

Paul Hilton/Greenpeace

If you knew the popular canned tuna you were eating might have been caught in slave-like conditions and was potentially contaminated, would you still want it? Would you give it to your kids?

I recently sailed on Greenpeace's ship, Rainbow Warrior, to check out tuna fisheries in the South Pacific. I encountered situations that shocked me. The way our tuna is caught, and way some boats store fish, is deeply disturbing.

I boarded more than a half-dozen fishing vessels in more than two weeks at sea. What I found most distressing was the lack of hygiene afforded to the fishermen who catch our tuna. It's difficult enough that they work near 20-hour shifts, but so often these boats are woefully deficient in basic sanitation and access to clean water.

Illegal Tuna Fishing Action in the Pacific Ocean

On one vessel, workers were punished for using the only toilet, which was reserved for the captain and officers. The people who actually catch and handle our fish were required to relieve themselves off the side of the boat. The stench was severe.

Signs plastered across these vessels enforced a $50 dock in pay if fishermen drank bottled water without the captain's approval. Clean water was for the officers; fishermen drank from the dirty and contaminated open jugs on deck.

If the poor sanitation or polluted water made the fishermen sick and they needed to rest or sleep it off, they'd get another $100 shaved off their pay. For a tuna fisherman in the early stages of his contract, that can be as much as two weeks of work. It's even more heartbreaking when you've had the opportunity to meet the kind of men that do this job on a daily basis.

On my last night on the Rainbow Warrior we were docked in American Samoa. One of our crew tapped me on the shoulder while I was eating dinner: "Lauren, there is someone here who wants to speak with you." He pointed towards the stairs and the look on his face illustrated in no uncertain terms that I needed to go with him.

Good God, what did I do? My mind raced. I entered the campaign office to be greeted by a man who had been following our journey. He said he knew things, had deep connections to the region and felt it was very important to tell me he knew about tuna fishing in the area.

I stood dumbfounded as he told me about even more egregious practices occurring on fishing vessels in the South Pacific. He said that at least two ships docked in the port were being investigated for environmental crimes.

Even more shockingly, he claimed that in some fleets it was standard practice to use tuna storage freezers for extra diesel storage. This meant that when a ship was low on fuel, officers could refill their diesel tanks from the freezer. Once empty, the freezer was filled with fresh tuna. If the tanks are were out, the diesel and chemical detergents used would most likely end up in the ocean.

Fishermen Stack Dead Tuna in Freezer in Pacific Ocean

To say I was disgusted is an understatement. I was already overwhelmed by what I had seen at sea but it left me utterly speechless to think that U.S. brands may be selling canned tuna that has been sitting in diesel tanks for months before being offloaded. It could be horrendously unsafe for all consumers.

Think about it. Imagine your friend pulling out a bunch of fish from the gas tank of his car and saying, 'no it's fine, my tank was empty!' I can guarantee you wouldn't let it go near your mouth, and you certainly wouldn't feed it to children.

None of us should eat canned tuna from any brand that fails to reveal their fishing practises or the provenance of the fish. Pole-and-line caught tuna is still our safest and most sustainable option. If not, there's a chance your tuna has come from fishing grounds which use unsustainable methods, treat workers poorly and potentially taint your food with diesel and noxious chemicals.

It's worth our health and the health of the oceans to support companies that never condone these practices and respect all the players involved.

This blog first appeared in September.