Email
Password
Remember meForgot password?
    Log in with Twitter

article imageAmazon's largest fish is facing extinction

By Karen Graham     Aug 13, 2014 in Environment
Fans of master-fisherman Jeremy Wade will remember the Animal Planet's "River Monsters" episode when he was rammed in the chest by a large Arapaima. While Wade practices catch-and-release, this majestic fish is being decimated in the wild.
A recent survey of fishing communities in the state of Amazonas, Brazil, published online Wednesday in Aquatic Conservation: Freshwater and Marine Ecosystems found that in some parts of the Amazon River basin, the Arapaima, which can grow to 10 feet in length and weigh close to 400 pounds, is already extinct. In other areas of the basin, their numbers are rapidly falling.
Researchers did discover one piece of good news. In areas where Arapaima fishing was regulated, their numbers have actually been increasing. This is a positive sign that conservation efforts could be working.
The arapaima (Arapaima gigas), or as it is commonly called, pirarucu, is the largest freshwater fish in South America, and one of the largest freshwater fish in the world. The longest Arapaima ever caught was 15-feet long, and weighed 440 pounds.These fish are rather unique because they can breathe air. They have a primitive lung, and the lung, working with the gill system allows the fish to breathe underwater.
How big can an arapaima get? Take a look at the scale in Jeremy Wade s left hand.
How big can an arapaima get? Take a look at the scale in Jeremy Wade's left hand.
DMAXItalia
They developed this system because they usually live in oxygen-poor waterways. They come up to the surface to breathe every five to 15 minutes and "gulp" a lungful of air. This makes them easy prey for fishermen using spears and homemade canoes. They spawn on the edges of floodplain forests.
Donald Stewart, a professor with the State University of New York at Syracuse's College of Environmental Science, and co-author of the study said that of the five known species of Arapaima, three have been considered extinct for decades in the wild. It is hard to imagine, but according to Stewart, Arapaima dominated fisheries in the Amazon less than a century ago.
While commercial fishing of Arapaima has been banned by the Brazilian government, they are still fished by the local Amazonian communities, and it is seldom regulated. The focus of the study was to find out if this unregulated fishing was having an effect on the population. This was centered on 182 fishermen with respect to fishing practices and management regulations, and was collected in 81 fishing communities.
The Arapaima population was found to be "depleted" in 76 percent of the fishing communities, "over-exploited" in 17 percent, "well-managed" in 5 percent, and "unfished" in only 2 percent of the communities. Arapaima was "extinct" in 19 percent of the communities.
Researchers found that 23 percent of fishermen in the communities harvested Arapaima regardless of the status of the population, while "compliance with the season regulation in communities with ‘over-exploited’ or ‘depleted’ populations (72 percent) was lower than in communities with ‘well-managed’ or ‘unfished’ populations (97 percent)," according to the study.
Fishing community along the Amazon River.
Fishing community along the Amazon River.
Bob Hite
"Fishers continue to harvest arapaima regardless of low population densities," said study leader Leandro Castello, an assistant professor of fisheries at Virginia Tech's College of Natural Resources and Environment, in Blacksburg, Virginia.
The team said the blame must not fall on the fishing communities alone for the demise of the Arapaima, but should be shared with Brazil's policy makers, who follow a line of "bioeconomic" thinking. "Bioeconomic thinking has predicted that scarcity would drive up fishing costs, which would increase the price and help save depleted species," Castello said. "If that prediction were true, extinctions induced by fishing would not exist, but that is not what has happened."
What is happening, according to the researchers, is a process called the "fishing-down" theory. This theory explains how a high-value, easy to catch fish can be fished to extinction. And that is what's happening to the Arapaima.
In areas where the Arapaima is scarce, the fishermen can't catch them in the traditional way, so they use other means, such as gill nets, which only deplete the fish further. These results support fishing-down predictions that show fishing pressure continues to occur even when fish populations are depleted. The study also pointed out that extinctions such as with the Arapaima will often go unnoticed because of geographical locations, illegal fishing and a scarcity of data.
More about Arapaima, primative long, Amazon tiver, breathes air, Overfishing
More news from
Latest News
Top News