In the last fifteen years, a fishery for the green sea urchin, Strongylocentrotus droebachiensis,has become the seventh largest in the Northeastern United States, and is the third largest in Maine behind lobsters and aquacultured Atlantic salmon (NOAA NR96-11, September, 17, 1996). Unsexed whole sea urchins or their processed gonads are shipped primarily to Japanese markets and to markets in France, Belgium, Greece, Italy and Turkey. Early unregulated harvesting and continued overfishing have drastically depleted once abundant field populations in the Gulf of Maine. In Maine during 1993, 41 million pounds of urchins were harvested and 26 million dollars were earned by the urchin industry. Since this peak harvest, urchin landings have quickly declined while the price per pound has increased. Recently, urchin fishermen, processors and state government agencies in New Hampshire, Maine and Massachusetts have attempted to coordinate their efforts to realize a sustainable urchin harvest. Various mechanisms for sea urchin aquaculture and stock enhancement have been identified and may provide high quality and high dollar value products in the absence of large annual harvests from natural populations.

Data from our previous Sea Grant efforts suggest that land-based facilities could produce high quality urchin gonads at least twice a year. Use of abundant food and photoperiod manipulation offer the possibilities of shortening the time to reach market condition (³15% gonad index) and of coordinating the availability of a high quality product with market demand. Such aquaculture techniques would maximize profit and reduce harvest pressure on natural populations. The land-based aquaculture approach is complimentary to stock enhancement and fisheries management of the natural harvest.

We envision this study as the final two years of our Sea Grant efforts on developing the technology for land-based aquaculture of the Northeastern green sea urchin.We will provide all the results of our studies on enhancing gonad quality and manipulating the reproductive cycle as personal communications with individual fishermen, at national and international meetings, in published form in refereed and industry journals, in a CD available from Sea Grant on the Biology and Aquaculture of the Northeastern Green Sea Urchin and in a continuing form on a Web site. Relevant new information from other interested individuals will be included.

Relevant Publications:

• Walker CW, McGinn NA, Harrington LH, Lesser MP (2001) Reproduction in sea urchins. In: Lawrence, JM (ed) The Biology and Ecology of Edible Sea Urchins. Elsevier Press, Amsterdam, pp. 5-26.



• Böttger SA, Walker CW, Unuma T (2004) Care and maintenance of adult echinoderms. Chapter 2 in development of sea urchins, ascidians, and other invertebrate deuterostomes: experimental approaches. Ettensohn CA, Wessel, GM and Wray GA (eds) Methods in Cell Biology 74: 17-38.



• Walker CW, Harrington LH, Lesser MP, Fagerberg WR (2005) Nutritive phagocyte incubation chambers provide a structural and nutritive microenvironment for germ cells of Strongylocentrotus droebachiensis, the green sea urchin. Biol Bull 209: 31-48.



• Walker CW, Unuma T, Lesser MP (2006) Reproduction of sea urchins. In: Lawrence, J (ed), 2nd edition, Edible Sea Urchins: Biology and Ecology. Elsevier, Amsterdam, The Netherlands, pp. 11-33.



• Böttger SA, Devin MG, Walker CW (2006) Suspension of annual gametogenesis in North American green sea urchins (Strongylocentrotus droebachiensis) experiencing invariant photoperiod – Applications for land-based aquaculture. Aquaculture 261: 1422-1431.



• Harrington LH, Walker CW, Lesser MP (2007) Gametogenesis in the green sea urchin, Strongylocentrotus droebachiensis. Invert. Biol. 126: 202-209.



• Unuma T, Walker CW (in review) The role of the major yolk protein in sea urchin reproduction and its relevance to aquaculture. Proceedings of the 12th International Echinoderm Conference, Durham, NH, August 2006.