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It Really Sucks Being a Tuna
The fishers of Pohnpei Island use the feeding patterns of seabirds to spot tuna. Commercial tuna fishers use a modern version of this method - helicopters. Overfishing is putting some tuna populations at risk of collapse. Saving these fish is made more difficult by the great distances these fish swim and the high price they fetch.
Depending on the species, a single tuna can sell for thousands of dollars. This creates a lot of incentive to catch as many tuna as possible. But this approach results in overfishing.
As tuna populations drop, their value increases, and it becomes even more lucrative to catch as many tuna as you can. Some species of tuna are now so valuable that it is economic to use helicopters and other expensive methods to catch them and bring them freash to market.
Some tuna populations have dropped by 90% since the 1950’s, and unless we preserve their numbers there will be no tuna left to catch.
One successful method for preserving fish numbers is to set aside areas as no fishing zones, called marine protected areas or marine reserves. With no fishing, fish numbers increase and they spill out of the MPA into areas where they can be fished.
But how do you protect a migratory species that can cross-cross the ocean several times throughout its life?
The answer may be to protect areas where tuna congregate, like migratory routes or spawning grounds. Traditionally, these areas have been used to catch a lot of fish with very little effort. If these areas are protected instead, tuna may have a better chance to rebuild their numbers and give us a continuous supply of food.
Fishing is a type of disturbance. Ecosystems can adapt to, and sometimes even benefit from disturbance, but like all types of disturbance, too much fishing lowers diversity and productivity. To ensure that we have a continued supply of tuna we need to fish these animals at a sustainable rate.
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