WWW.WAS.ORG • WORLD AQUACULTURE • JUNE 2019 49 Alaskan Pacific geoduck fishery has expanded greatly since its opening in 1983 (Brickey et al. 2012). In Mexico the fishery is even more recent, beginning in 2000, and various surveys suggest that fishermen are harvesting two distinct species of geoduck (P. generosa and P. globosa) from both coasts of Baja California, Mexico (Pérez-Valencia and Aragó n-Noriega, 2013). Geoduck harvesting in Washington State (US) and BC (Canada) has been an US$80 million industry in recent years (Washington Sea Grant 2013). In Mexico, the gross income from geoduck is estimated to be between US$18-30 million (Aragó n-Noriega et al. 2012, FerreiaArrieta et al. 2015). Geoduck Aquaculture The recent rapid increase in demand for geoduck has resulted in increased pressure on wild populations, prompting aquaculture research and development of this clam. Geoduck aquaculture is very much in its infancy in North America. Farming of the targeted species began on a trial and error basis, with very little help from rigorous scientific research and extension. Knowledge of the biological and ecological characteristics of the geoduck life cycle, especially during larval and juvenile stages, is essential to design aquaculture strategies. There are two species of geoduck of aquaculture interest in North America – the Pacific geoduck and the Cortes geoduck Panopea globosa (Figs. 3 and 4). For Pacific geoduck aquaculture, development initiatives have been implemented in the USA, Canada and Mexico. For Cortes geoduck, aquaculture has been undertaken only in Mexico. The life cycles of these two species are similar, although their geographic distribution limits are not the same (PérezValencia and Aragó n-Noriega 2013). Geoduck Seed Production Historically aquaculture development of any new species initially depends on collection of seed or juveniles from wild sources. For example, aquaculture of oysters and mussels started with wild-source seed and then various techniques were developed over time to capture wild spat. Spat collected from the wild have usually passed the most critical stages of their life cycle when mortality is highest and have good survival rates when stocked into culture facilities. But collection of wild spat of geoduck is not feasible or practical. Unlike oysters or mussels, geoduck postlarvae (juveniles) burrow into the ocean bottom, making it difficult to collect from wild sources. Also, heterogenous distribution and variable recruitment limit the opportunity to collect wild-source larvae or juveniles. Hatchery production technology is the only viable option to procure a sufficient number of seed for aquaculture development of this species (Marshall 2012). FIGURE 2. Geoduck clams in a supermarket in Vancouver, Canada. FIGURE 3. Harvested broodstock of Pacific geoduck. FIGURE 4. Harvested broodstock of Cortes geoduck. (CONTINUED ON PAGE 50)
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