Oyster Culture in Brazil: An Emerging Sector Along the Amazon Mangrove
With its long coastline and large markets along coastal cities and towns, the potential for oyster culture in Brazil is high, reports Bonnie Waycott. Last year, a study in Pará state along the eastern Amazon mangrove coast used socio-economic data to analyse the management and future development of Pará's oyster culture and present an overview of the situation.
The first studies on Brazil's oyster culture began in the 1970s in Santos, São Paulo state, southeast Brazil. Today, the most commonly cultured species in southern Brazil is Crassostrea gigas due to cooler water temperatures that are best for growth. In southeast, northeast and north Brazil, the native oyster species Crassostrea gasar and Crassostrea rhizophorae have been cultured for the past 15 to 20 years.
In the state of Pará in northern Brazil, oyster culture is even more recent, beginning in 2006 with native mangrove oysters. Data from the Brazilian Institute of Geography and Statistics (IBGE) shows that in 2014, it produced only 8 tonnes (0.04%) of C. gasar and in 2016, with annual production of around 42 tonnes, came only 6th in Brazil's national ranking. However, recent investments have allowed production to grow significantly, despite a lack of organisation and long experience in the oyster culture industry.
In light of this, Dr. Dioniso de Souza Sampaio of the Laboratory for the Conservation of Biodiversity and Waters at the Federal University of Pará’s Institute of Coastal Studies began evaluating Pará's oyster production chain. Last year, together with co-authors Dr. Claudia Helena Tagliaro, Dr. Horacio Schneider and Dr. Colin Robert Beasley, he produced an overview of the state's oyster culture and development. It states that with little impact from urban and industrial development, and a mangrove coast that's relatively well protected, the potential for Pará is high.
"I assisted the first oyster farmers in Pará between 2005 and 2006 and supported their initial attempts in oyster culture," he said. "I wanted to develop my research because I'd only seen the results of studies on just a few culture units and wanted to evaluate further. My aim was to evaluate the production and supply chains along the coast, look at positive and negative aspects and make recommendations for the sector's future."
Dr. Souza Sampaio's previous experiences in Pará weren't the only reason for his research. Up to 2012/2013, only a couple of studies had been done on individual oyster growing associations in the region and it wasn't clear how oyster culture was developing.
"Through surveys and interviews, we found various differences in production where oyster farming is conducted," said Dr. Souza Sampaio. "Some are due to rainfall and freshwater input from rivers to the mangroves. Coastal areas with higher salinity and temperature values, and waters that are 4 - 6m deep, are associated with faster growth, for example in the Augusto Corrêa municipality, but consistently low salinity is not particularly suitable for growth, even though it's associated with greater numbers of seed. Curuça, in the west, which supplies almost all seed for oyster growers along the Pará coast, has such conditions. Other differences are in the oyster growers' efforts, investment and management. Some growers' associations invest more into developing, monitoring and managing their oyster culture than others. It's also interesting that in Pará, although oyster culture is growing, very few associations are entirely dedicated to it. Most members are part-time and usually farm cattle and crops."
Commercial oyster farming in Pará is done through seven associations in five municipalities along the northeast where salinity and tidal conditions are suitable. Seed is harvested from water entering the mangrove forest tidal channels on each tide, using collectors (rectangles cut from 2L plastic bottles). These are strung vertically from small wooden structures and left for around 60 days. The seed is then transferred to fine mesh bags and placed on wooden structures called tables, very low down in the mangrove tidal channel. Every two months, oyster farmers clean the bags, remove dead oysters and measure and sort the live ones, which are placed in new bags as they grow and depending on size. In four to six months, the oysters reach a 60mm commercial size. The mangroves, meanwhile, are essential to oyster culture. They produce biomass, which is broken down and redistributed along the coast, while the tides bring back and forth nutrients, organic matter and algae for the oysters. In turn, oyster culture protects the mangroves by filtering water, which is beneficial for algae, invertebrates and fish.
"Pará's environment is ideal for oyster culture, but there are some challenges," said Dr. Souza Sampaio. "For example, there is a need to strengthen, diversify, become economically independent, and socially and environmentally responsible. Farmers also need to harvest seed from a range of locations, not just a single one, because if anything happened to interrupt the supply of seed from that location, the sector could collapse. With a potentially large market for oysters, more investment in marketing and commercialisation will be required too."
Since the publication of Dr. Souza Sampaio's research in Reviews in Aquaculture in 2017, researchers in Italy, Malaysia, Thailand, the Philippines, Korea and Australia have been in contact. With all eyes seemingly on Pará and two new projects in the works, Dr. Souza Sampaio believes in the significance of sharing information not only amongst scientists and policy makers, but also with oyster farming communities.
"Having contact with researchers from several countries for future partnerships is very important," he said. "Usually, when talking about oysters in Brazil, Santa Catarina state is the primary reference but Pará is now getting attention so we are waiting to see what will happen. I'm now involved in an outreach project to build legislation to protect Pará's natural oyster beds, and a network project called Technological Basis for the Sustainable Production of Native Oysters in Northern and Northeastern Brazil. We’re also cooperating with Conservation International in Pará on the possibility of certifying sustainable oyster culture. I'm excited to see what the future holds."
Dioniso de Souza Sampaio, Dr.
Federal University of Pará/ Institute of Coastal Studies
Professor and Research
Researcher ID: G-1544-2015
Curriculo Lattes: http://lattes.cnpq.br/2193736281754259
E-mail: firstname.lastname@example.org e email@example.com
Colin Robert Beasley, Dr.
Federal University of Pará/Institute of Coastal Studies
Professor and Research
Researcher ID: J-2615-2012
Currículo Lattes https://lattes.cnpq.br/6310836748316181
GPG public key: 4BD54D27
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