Among seventeen species of scallop found along the extensive 7,400 km Brazilian coastline, the lion’s paw scallop Nodipecten nodosus, the largest of all, has been identified as the best scallop candidate for mariculture in Brazil. This scallop can attain a shell length of up to 18 cm. It is commonly found along the southern coastline of Rio de Janeiro state in a depth range of 10-25 m, mainly affixed to hard substrates, usually rocks. It is occasionally also found on sandy sea bottoms in close proximity to island or mainland shorelines. The lion’s paw scallop is by far the most abundant scallop. The species has excellent attributes for domestication. It is relatively easy to manage using common scallop lantern net culture systems and husbandry techniques. Scallops grow fast in the warm, clean coastal waters of the southeastern coast of Brazil, reaching 80-100 mm shell length within 12 months of culture (Lovatelli et al. 2008; Sühnel et al. 2012).

The culture techniques employed have low environmental impact and scallop filter-feeding habits makes this bivalve very attractive for culture because it does not require external food input. The live, fresh-from-the-farm, sustainable shellfish product, continues to have positive consumer acceptance, stimulating the development of good and growing market demand (Lovatelli et al. 2008). A government initiative was launched in 1994 to promote regional shellfish culture as a means to reduce the risk of extinction from overfishing and to promote marine resource conservation.

The southeast region of Brazil has a very special coast, full of cut shorelines and many nearshore islands, most without urban pressure or polluting runoff. The region has many sheltered areas including bays and inlets, but also many open areas with greater circulation influenced by open ocean dynamics. This diverse coastal morphology, combined with strong oceanographic influences, results in a variety of environments suitable for diverse mariculture practices and approaches. In addition, the tropical climate, with an average surface water temperature of 23-25 C, is ideal for scallop production, allowing year-round production.

Most scallop farming in Brazil is concentrated at Ilha Grande Bay, near the municipality of Angra dos Reis. This region has a rich marine biodiversity, ranging from benthic organisms to top trophic predators. Such biodiversity, combined with the unique coastal geomorphology, make this region very attractive to ecologists and nature lovers and for ecotourism and diving.

This region is strategically located between two big economic centers, São Paulo to the south and Rio de Janeiro to the north, which are the main urban consumer markets for mariculture production from the region. The local communities in the region are mostly represented by artisanal fishermen families, whose family and cultural connections with the ocean extend back many generations. The beautiful and relatively un-spoiled coastal environments and social and cultural factors have combined to allow this region to become a major scallop mariculture producing area, with a focus on sustainable production. The sector has the support of and is integrated well with the local community and is also supported by guidance provided by local and Federal Brazilian government oversight.

Scallop production fits well into the social and physiographic context of this region and presents an opportunity for development of a highly profitable mariculture sector. Many former fishermen have adopted scallop culture as their new full-time occupation. Interest from the local community to become scallop producers is increasing rapidly, given that the activity is deeply rooted in their culture and ancestral life practices, and presents a new and modern way to earn a healthful living from the sea. A bonus is the timeliness of integrating sustainable aquafarming practices into the new and developing industry. This trend will promote long-term ecosystem protection and regeneration, benefiting the biodiversity of the natural marine resources in this region.

Because fresh scallops command high prices in the marketplace, scallop mariculture provides a greatly needed source of increased income for local fisherfolk, their families, and the community at large. In addition, as health awareness and the root causes of devastating diseases such as heart disease and arteriosclerosis become better understood by the general public in Brazil and by coastal populations in particular, there is an increasing demand for seafood, including scallops, to replace other forms of animal protein in diets and on menus. This is especially true for fresh, locallyproduced seafood products that, in addition to their noted health benefits, can command a price premium in the marketplace.

Federal government incentives and the private sector and producer associations have been supporting scallop culture through research activities, seed production, social programs and facilitating regulatory pathways to further develop the activity. In addition, the local Department of Fisheries and Aquaculture has agreements in place with a large regional hatchery (IED-BIG) and has played a major role in monitoring and assisting local producers with farm siting advice, assistance with production methodology and husbandry techniques, monitoring and biometrics, harvesting techniques, and even commercialization and marketing. This government support and interaction has helped to ensure that the nascent scallop mariculture industry of the region will have a better chance for survival, with long-term and sustainable growth.

Seed Production

The first attempts of spawning under controlled conditions in the region occurred about 20 years ago. Hatchery capacity has grown slowly and currently stands at about 20 million spat per year. This number is sufficient to meet the needs of all current scallop producers and government research centers. In addition to seed production, hatcheries are involved with social projects, including “how-to” workshops, specialized training, and environmental educational programs for producers.

Larviculture methods are based on industry-standard, wellpracticed protocols, starting with obtaining fertilized eggs from broodstock scallops collected from the wild that are greater than 75 mm in shell length and older than 18 months. Gravid broodstock are first exposed to increased water temperature in the laboratory, i.e. from 20 to 24 C (Rupp et al. 2004, Sühnel et al. 2014). Because scallops are hermaphrodites, the process is closely monitored to avoid self-fertilization and decrease stock inbreeding. Spawned embryos are then transferred to larviculture tanks and fed initially with a mixture of cultured microalgal species, mostly Isochrysis galbana, Pavlova lutheri and Nannochloropsis oculata. After the fifth day, four additional species (Chaetoceros calcitrans, C. gracilis, C. muelleri, and Bellerochea polymorpha) are blended with the first three species to form the larval diet.

After the larval rearing period, pediveligers are transferred to settlement tanks. Once settlement occurs, larvae are culled to specific densities, with continued feeding of the seven-species microalgal mixture. After 30 days, shell formation starts to occur and the tiny scallops are transferred to the sea in settling lantern nets for another 30 days to allow continued growth on natural feeds and for shell hardening, facilitated by the natural bicarbonate titers of the coastal seawater. Finally the mature seed scallops are transferred to nursery lantern nets, and after an additional 30-d nursery period (now approximately 90-95 days total in the nursery phase), the young scallops are ready to be stocked into lantern net systems for growout.

Read the rest of this article in the September 2016 issue of World Aquaculture Magazine here