The Amazon river basin’s largest fish, arapaima, is already extinct is many communities whereas its number in other parts of Amazon is extremely low, according to a new study. A century ago, the giant fish dominated the Amazon river, but today it’s on the verge of extinction due to overfishing. Arapaima weighs about 400 pounds (181kg) and measure up to 10 feet (3 meters).

Amazon Arapaima

Overfishing in Amazon leads arapaima close to extinction

Scientists found that arapaima populations have gone extinct in eight of the 41 communities they studied. On average, the fish’ population was extremely low. Results of the study appeared in the journal Aquatic Conservation: Freshwater and Marine Ecosystems. Scientists trained eight fishermen to count the fish as part of the survey.

Arapaima is the largest freshwater fish in South America. Researchers concluded that the effect of extreme fishing in Amazon was worse than previously believed. Arapaima is easy to catch because of their unique ability to breathe air. They have primitive lungs in conjunction with a gill system. So, they come to the surface every 5-15 minutes, and become victims of fishermen.

There have been two theories about the extinction of fish. The bio-economic theory says that fishing doesn’t lead to extinction of a species because fishermen move away from depleted resources. The alternative fishing-down theory predicts that the easy-to-catch, large, and high-value fish will be fished to extinction.

Even fishers know that the population of Amazon’s largest fish is declining

Researchers, led by Dr Leandro Castello of Virginia Tech, wanted to find out how healthy the arapaima population in the Amazon region was. They also wanted to know which theory these Amazon fisheries supported. They interviewed 182 “expert” fishermen in 81 communities covering about 400 miles of the Amazonia floodplains. They carried out fish counting in 41 of these communities.

They found that arapaima populations were well-managed only in 5% of the survey area. The fish populations were depleted in 57%, locally extinct in 19%, and over-exploited in 17% of the survey area. In only 2% communities arapaima were un-fished. What’s more, more than 75% of the fishermen interviewed said that the arapaima population in Amazon has declined in recent years.

Scientists concluded that the results of their study support the fishing-down theory rather than the bio-economic one.