Seafood Surprise: A Third of This Fish Species Faces Extinction

A new study finds that freshwater shrimp are disappearing—along with jobs for fishers around the world.
Shrimp fishers on the Great Lake of Cambodia. (Photo: Thierry Falise/LightRocket via Getty Images)
Apr 2, 2015· 2 MIN READ
John R. Platt covers the environment, wildlife, and technology and for TakePart, Scientific American, Audubon, and other publications.

Two years ago the unthinkable happened: Maine was forced to shut down its shrimp-fishing season after the population of the local species almost completely collapsed. Fishers lost work, and hungry consumers found themselves up a scampi without a crustacean.

Could the same thing happen elsewhere? A worrying new report from the International Union for Conservation of Nature suggests just that. The study finds that at least 28 percent of the world’s freshwater shrimp species are now threatened with extinction owing to pollution, dams, invasive species, and climate change.

Although few of these species make their way to grocery stores in the United States, the IUCN warned that people in some of the world’s poorest communities depend on freshwater shrimp for their livelihood. This includes many communities in Asia and Africa, where artisanal fishing practices are an important part of the cultural heritage.

Protecting shrimp, therefore, is more than about just protecting these species. It’s also an important way to protect people. The study called shrimp “an excellent, but overlooked, flagship group in freshwater conservation.” As an example, it cites a 2013 report from the Institute for European Environmental Policy that found that projects that restored wetlands—a key type of shrimp habitat—resulted in increased income and better access to fish and other food in the surrounding communities.

For some of these species, the threat may already be too great. Two shrimp species—including the Pasadena freshwater shrimp, from California—have now been declared extinct as part of this study. Ten more species of shrimp have been declared “possibly extinct.” Some of them haven’t been seen for decades.

“I don’t think we were surprised by the overall number being threatened,” said Sammy De Grave of the Oxford University Museum of Natural History, who led the research project that examined all 763 known freshwater shrimp species.

The IUCN Species Survival Commission Freshwater Crustacean Specialist Group had already examined crabs and crayfish, which live in similar habitats. Those studies found that 32 percent of crabs and 31.5 percent of crayfish species are threatened with extinction.

What surprised the team was that some species they expected to be in good shape were revealed to be at risk once they looked more closely.

“There were some species which I had firsthand knowledge of, having collected them in their native range, which I thought would be fine,” De Grave said. “But they ended up as threatened.”

Freshwater shrimps live in a variety of habitats, including lakes, streams, freshwater springs, and caves. This makes them vulnerable to disruptions in the local water supply. One U.S.-based species, the Alabama cave shrimp, is only known to live in four cave systems in the state for which it is named. The species has been declared endangered because the groundwater it depends on has been tapped for agricultural irrigation.

Another surprise was that the researchers could not collect enough data to assess the extinction risk of 282 freshwater shrimp species, or 37 percent of the total. Many of these “data-deficient” species live in China and Africa.

“Many of the Chinese data-deficient species were because of poor locality details in the original descriptions,” De Grave said. “If we could figure out exactly where they live, we could do a proper assessment, and I suspect quite a few would then be threatened.”

The study makes several recommendations to help the world’s freshwater shrimp, including protecting key habitats and implementing new methods to protect water resources. Meanwhile, the next step is to learn more about the ecological needs of all shrimp species and fill the gaps in knowledge of the data-deficient set. De Grave said he is now trying to get back out in the field to track down some of the Chinese species the team couldn’t find in their initial work.