This Japanese Fisherman Discovered Bolivia’s Only Giant Freshwater Clams

What links a Japanese fish farmer, a Peruvian Chilean chef, and a Bolivian restaurateur?

Freshwater clams and a land-locked Latin American nation, obviously.

Making the obscure habitat of southeast Bolivia their home, Gustavo Mizushima's clams recently caught the attention of chef Jaime Barbas García and restaurateur Jorge Calvo from the Jardin de Asia restaurant in Santa Cruz de la Sierra. But for the second generation Japanese fish farmer, his discovery of the mollusk was slightly more accidental.

"I'd get in the pools to go fishing and one day, I trod on something sharp," remembers Mizushima. "Thinking it was a stone, I picked it up to throw it out of the pool and saw it was a big clam. That was around 20 years ago."

While clams first appeared on Earth around 488 million years ago, the story of Mizushima's large freshwater variety begins in 1945, when the Bolivian government granted green cards to 270 Japanese families at the end of World War II. Given 50 hectares of virgin land, these issei or "first generation" went on to found several communities near Santa Cruz de la Sierra.

With a plot of land on the outskirts of the San Juan Japanese Colony community, Mizushima's parents set to work to make the most of their virgin Amazonian pasture, producing rice and vegetables. But it wasn't until his dad, Katashi, dug a hole in the ground and a geyser spurted 10 metres of water into the air that the family realised they were above a series of underground wells, perfect for fish farming.

Today, paddy fields surround Mizushima's property and the farm is populated with palm and almond trees, as well as an organic garden stuffed with ginger plants and vegetables. He retains cultural traditions, greeting visitors with homemade sake and proudly showing off his collection of 300 bonsai trees and 35 freshwater pools breeding river fish like paiche, pacú, and boga.

Mizushima estimates that he has around 300 kilos worth of clams on his land, all bred naturally. With some measuring the size of an adult human hand, he and his family would eat the clams straight from the dark brown waters.

But how on earth did the mollusks reach this part of Bolivia?

"I just don't know," Mizushima admits. "Some experts say birds carried them in, attached to their feet. It's possible. Personally, I think birds ate them but didn't digest them very well, and pooed them out."

It was Mizushima's fish distributor and friend Ueno Katsuyuki who hooked him up with García and Calvo, but he is none the wiser as to how the clams found their way to Bolivia.

"There's a river nearby that's always flooded and clams have always lived in it," he says. "The thing is, no one has ever dared to eat them. But that's set to change now."

According to Peruvian marine biologist and marine biology teacher at Universidad Cientifica del Sur Angel Perea De La Matta, the clam's appearance is a logical, if curious, phenomenon.

"Bivalves can live in saltwater or freshwater and biologically, clams can live in different regions as they only need a stratum of sand or clay," he says. "It's quite peculiar that they are in Bolivia, and they must have been there for thousands of years. There are bivalves in the Amazons that form part of the ecosystem so they must be native fauna and can live easily in this part of of Bolivia."

The local community has never shown much interest in whether Mizushima's clams are for sale or even edible, but Calvo is excited to experiment with a newly discovered, Bolivian product. The restaurateur ordered a microbiological report on one of the 400-gram clams in May from a Santa Cruz lab, which later confirmed it was edible.

The large clams will now feature on García's menu alongside other autochthonous Bolivian products such as royal quinoa, achachairú herbs, and trout from Lake Titicaca. The chef also has plans to include the mollusk in his ceviche, sushi, and batayaki dishes.

Despite the clams' seeming abundance, García and Calvo want to continue with Mizushima's low impact farming methods.

"I hope they're careful with this new food resource and can sustain a population in order to maintain a dish in a restaurant, even if it is seasonal," says De La Matta. "I hope they don't use young clams, which haven't yet reproduced, and use adult ones in order to look after this wild population."

The pair say they are working with Mizushima to farm the clams as naturally as possible, and aim to stick to manageable quotas and sizes.

"Once we clean it up and remove the mud, the texture is the same as a saltwater clam, though it tastes a little bit sweeter," adds García. "The inside of its shell is pearly so we are also using it as part of our dinnerware."