The Arapaima fish, considered to be biggest fish and commercially important one at the Amazon Basin, went extinct in a number of local fishing communities, a group of researchers revealed in a study published in the latest issue of the Aquatic Conservation journal.
The 10-foot or three meter long fish, weighing 400 pounds or more, conquered Amazon’s fisheries a century ago.
“Arapaima spawn on the edges of floodplain forests and come to the surface to breathe every 5 to 15 minutes, when they are easily located and harpooned by fishers using homemade canoes,” Caroline C. Arantes, fish biology and fishery management expert as well as wildlife and fisheries science doctoral student in Texas A&M University, said in a statement.
Among the five known arapaima species, three haven’t been visible for many decades already, according to professor Donald Stewart of the State University of New York.
The scientists involved in the study compared ordinary bioeconomic theory with the fishing-down theory that is less known.
“Bioeconomic thinking has predicted that scarcity would drive up fishing costs, which would increase price and help save depleted species,” explained Leandro Castello, study leader and fisheries assistant professor at the College of Natural Resources and Environment in Virginia Tech. “If that prediction were true, extinctions induced by fishing would not exist, but that is not what has happened.”
The researchers interviewed 182 fishers from 81 communities as chosen by their colleagues and on counts of fish in 41 fishing communities. Results of the study showed that arapaima are already extinct in 19 percent of the communities, depleted and upcoming extinction in 57 percent and overexploited in 17 percent.
Castello said the downside is that fishers push through collecting arapaima irrespective of low population densities. The upside is communities have instigated rules on fishing, imposing minimum size of capture and restricting the use of gill nets, which David McGrath of San Francisco’s Earth Innovation Institute said prevent further extinctions of arapaima.
Castello, however, added that cast nets have been allowed “because they are much more selective yet they yield abundant fishes for local consumption, so food security for the community is not compromised.”
Researchers also said the recent findings showed how many of these extinctions are likely going unnoticed and that fishers are besieged by the lack of alternatives economically.
Yet with the changes seen in the Amazonas State in Brazil, Castello said that there’s room for some changes and improvements, like things have been rehabilitated with arapaima populations previously overexploited now booming because of good management.