After the gold rush: A review of Artemia cyst production in northeastern Brazil

The genus Anemia (Crustacea; Anostraca) is a complex of sibling species and superspecies defined by the criterion of reproductive isolation. Two sexual species are represented in the New World: Anemia persimilis and Anemia franciscana. In Brazil, Anemia franciscana populations are found on a year-round and permanent basis in Rio Grande do Norte as a result of inoculations made in Macau in April 1977 with cysts from a San Francisco Bay (California, USA) stock. Through the years, introduced Anemia dispersed to over 40,000 ha of saltworks and became an important asset in the development of a successful shrimp (Litopenaeus vannamei) culture industry in northeastern Brazil. On a yearly basis, a substantial part (approximately 20 %) of the 20 tonnes of cysts currently used by the Brazilian shrimp culture industry is harvested in local saltworks. However, there are growing concerns about the long-term sustainability of current harvesting practices. Not only Anemia is being collected in a reduced area (several hundred hectares of saltworks have been converted to shrimp grow-out ponds), but most importantly, there are indications that overharvesting of cysts has caused a directional reproductive shift to ovoviviparity (direct production of free-living nauplii) in local brine shrimp populations. The sustainable harvesting of Anemia franciscana cysts in Brazilian salterns is critical for ecological, social and economic reasons. Careful management of this essential resource requires a science-based approach with eyes open for the possible effects of exploitation-induced selection before it seriously impacts the viability of this emerging form of extractive aquaculture.