The first few weeks of this blog have heavily featured the impact of agriculture but a recent article has encouraged me to have a few posts dedicated to the impacts of our diets on oceans.
More than 70% of the Earth's surface is covered by oceans but marine life faces increasing human threats.
Despite the plentiful supply of tuna eaten, tuna fishing is often unsustainable.
Tuna fishing has increased by more than 1000% in the last 60 years with 6 million tonnes of tuna caught each year. There are no new fishing grounds left and we are catching tuna at the highest rate, potentially driving these species to extinction, particularly Pacific bluefin tuna.
Environmental groups have petitioned to have Pacific bluefin tuna listed as endangered with only 1.6 million bluefin tuna remaining, of which only 140,000 are of spawning age. Nearly all tuna today are caught before they have spawned more than once or twice in their lifetimes at age 5. Populations of Pacific bluefin tuna are estimated to have fallen to 2.6% of their historic size.
However, even when the situation is bad, it may still be possible to turn around.
Here are three reasons to be cheerful:
1. In recent years, the Western and Central Pacific Fisheries Commission and the Inter-American Tropical Tuna Commission - the groups responsible for Pacific bluefin tuna management - have come to an agreement to recover populations to 20% of historic levels by 2034. 20% is 7 times the current population!
2. Fully farmed bluefin tuna bred from eggs is now possible after decades of research, and exports have begun. 30% of bluefin tuna is currently farmed but this mostly involves the capture of wild juveniles to fatten in pens, depleting tuna populations. Fully farmed tuna could therefore be a massive leap forwards.
3. A new tool can identify the origins of bluefin tuna, which is essential for preventing illegal fishing and encouraging sustainable fisheries. This method is cost-effective, accurate, and non-invasive, using around 100 genome markers. Differentiation between wild tuna that has been fattened, and fully farmed tuna, will be possible, and increased prices for premium products will be much easier to apply.
So there you have it, the good and the bad of tuna fisheries. Although bluefin tuna populations are depleted, efforts are being made to change. Do you think there is still hope for bluefin tuna?