Conservation news

Lakes in community hands spur gains for people and fish

  • In an 8-year study covering a 500-kilometer stretch of a tributary to the Amazon, a team of scientists from Brazil and England found that the often-overfished arapaima came back in community-managed lakes.
  • Protected lakes had populations more than 30 times those where commercial fishing was allowed.
  • The team estimates that each protected lake is worth about $10,000 per community in revenue from arapaima stocks annually.

The arapaima (Arapaima gigas) is the largest freshwater scaled fish in the world, topping out at 2.75 meters (9 feet) and weighing up to 200 kilograms (440 pounds) – at least, those are the largest ones we’ve recorded in the muddy waters of the Amazon Basin. But its large size and penchant for surfacing to breathe air – an adaptation that helps it survive in poorly oxygenated Amazonian tributaries – has led to its decimation in some areas to feed our hunger for protein.

Now, a recent study published in the journal Scientific Reports has found that populations of arapaima, or pirarucu as it’s known locally, are on the mend in the watershed of a 500-kilometer stretch of the Juruá River in Brazil, thanks to communities coming together to protect this fish that’s become a linchpin of their diets and their economies.

Over the course of eight years, João Vitor Campos-Silva of the Universidade Federal do Rio Grande do Norte in Natal, Brazil, and Carlos Peres of the University of East Anglia in Norwich, England, documented huge gains in stocks of arapaima in protected lakes along this stretch of river, where populations were about 33 times larger than in “open-access” lakes open to anyone to use, including commercial fishermen.

Arapaima can grow to 200 kilograms (440 pounds) and are an important source of protein and income in the Amazon. Photo courtesy of Carlos Peres

An important aspect of the study area was the fact that it included a large part of the ecosystem. Even though the subsistence lakes had fewer adult arapaima than the protected lakes, likely because fishers had targeted bigger fish, the authors speculate in their report that these lakes still offered a safe haven for young fish that the open-access lakes didn’t provide.

“Undoubtedly, arapaima management is a rare window of opportunity to [harmonize] the often incompatible goals of sustainable resource management and poverty alleviation,” Peres said in a press release.

The communities involved in this study put together a set of “fishing accords” that created three categories of lakes, open-access, subsistence and protected. In subsistence lakes, local, but not commercial, fishers are allowed to harvest fish. Protected lakes only allow a short period for harvest each year regulated by strict quotas.

These communities took on the responsibility of guarding the protected lakes from illegal fishing, which both over-strips the ecosystem of fish and depresses local markets because these boats can sell their catch for less than aboveboard operators.

The authors undertook an 8-year study along the Juruá River and found significant gains in arapaima populations in community-protected lakes. Photo courtesy of Carlos Peres

“Boosting these fish populations offers not only much-needed animal protein for the local community but also an unprecedented source of income,” Peres said.

In fact, Campos-Silva and Peres likened a protected lake to “a high-interest savings account,” figuring that each one was worth more than $10,000 to its community. The authors write that, as community members began to see arapaima stocks recover, they became more enthusiastic about protecting the lakes from which they were deriving benefit.

In light of these advantages, the researchers argue that this type of community-centered approach offers an economic alternative to the often-politically fraught process of setting aside reserves.

“Conservation initiatives in Amazonian floodplains are often a huge challenge due to lack of governance, investments and human resources,” Campos-Silva said in the release. And, he said, they’re often focused on terrestrial landscapes, not aquatic environments.

A community harvests arapaima, the largest scaled freshwater fish in the world. Photo courtesy of Carlos Peres

The authors caution that “fishing agreements alone are not a panacea and cannot substitute the creation of large protected areas.”

Still, “[Decentralizing] conservation policies to communities and local stakeholders can be powerful and effective,” Peres said in the release.

And the team sees great potential in replicating this strategy elsewhere.

“The Brazilian government and others stakeholders should invest in incentives to solve market bottlenecks and consolidate this rare sustainable development opportunity,” Campos-Silva said.