In the southern state of Paraná, a large inlet in the middle of dense Atlantic forest forms the Bay of Guaratuba. This is one of Brazil's most biologically rich ecosystems. On the calm waters of the vast bay, the tranquility is only broken by the occasional sound of human activity.

Nereu de Oliveira discovered this place about a decade ago. He liked the area so much that he decided to leave his job as a lawyer and open an oyster cultivation site on the bay. He built a restaurant and environment education center and started to get interested in new ways to protect the environment.

In 2005, he decided to partner with Cultimar, an initiative of the Federal University of Paraná. Cultimar's goal is to support sustainable aquaculture in Brazil.

Oliveira left his carreer as a lawyer to pursue a life in aquaculture

Oliveira told DW that he farms oysters in a sustainable way, instead of extracting oysters from the wild population. This way, the shellfish continue to fill their place in the ecosystem.

In order to encourage oyster farmers to support sustainable practices, Cultimar has created a health certificate. This gives local oyster farmers - who are so proud of their world-famous oysters - an official standard to aim for.

Lab certification

Scientific testing of oyster quality is done at a university in Paraná's capital city Curitiba. Within the laboratories, water gurgles and bubbles in basins where ocean organisms are kept for examination. Researcher Karin Yamashiro explained how the oyster testing works.

"We open them up, collect the oyster as well as the intervulvar liquid, put it in sterile machines that homogenize the samples, then extract the liquid - one milliliter to test for E. coli and staphylococcus, another milliliter to identify salmonella," Yamashiro said.

Ostrensky says environmental education has shifted thinking in this region

In addition to scientific monitoring, the Cultimar project works to distribute new knowledge and practices in local coastal communities. Antonio Ostrensky heads the university's aquaculture research institute. "The fact is, you can't just talk science to the oyster producers. They're not going to understand the science. You have to translate it for them. Simplify," Ostrensky told DW.

The health certificate is something any oyster farmer can understand and appreciate. The technical process adds value to the oyster and the certificate provides an easy tool for marketing sustainable practices.

And consumers like the extra safety measures. Oysters are ocean organisms that filter water and can carry disease. So consumers are willing to pay more for oysters they know are certified as safe for consumption.

Food security

As Brazil's economy expands, mariculture is becoming more important, especially because it has a lower impact on the environment than other food production activities. Communities involved in new sustainable oyster production also have an opportunity to generate stable income. They are also able to stay on their land. In nearby coastal regions, developers have looked to expand high-rise residential communities with waterfront views, instead of finding ways to preserve the environment and support local industry.

Small-scale production of oysters is a sustainable alternative to traditional fishing

Oyster cultivation is a good alternative to the overfishing that used to take place in Guaratuba before Cultimar came into the picture. Ostrensky says the project has shifted peoples' thinking.

"Nowadays if you go there, you see a culture that involves much more than production; it involves environmental education, restaurants, tourism," Ostrensky said. "I think the scale we've been working on has brought about a great transformation."

Guaratuba oysters are considered some of the tastiest in the world

Oliveira says that a continued focus on oyster cultivation will help preserve the region, because healthy oysters demand water free from impurities. He agreed with Ostrensky that the project has transformed the region.

"You see an evolution in the people of the region. Altogether, it ends up improving the people's lives," Oliveira said. "The world needs protein for human consumption. Fish, oysters, shrimp and other seafood can all contribute to a healthy diet."

Oliveira even believes that sustainable fishing practices in Guaratuba could be replicated in other regions of Brazil, and around the world.