A pilot study on gonad enhancement in kelp-fed Newfoundland green sea urchin, Strongylocentrotus droebachiensis

Trueman, Samantha Cristine (2019) A pilot study on gonad enhancement in kelp-fed Newfoundland green sea urchin, Strongylocentrotus droebachiensis. Masters thesis, Memorial University of Newfoundland.

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Abstract

Sea urchin gonads, also known as “roe” or “uni”, are a highly prized delicacy in Asian and European seafood markets. Green sea urchin, Strongylocentrotus droebachiensis, produces one of the finest and most widely marketed roe in Asia, including top markets in Japan and Korea. Green sea urchin is abundant throughout eastern Newfoundland and holds a large potential for sea urchin roe enhancement and aquaculture, however no such industry has been developed despite initial research attempts in the late 1990s. In order to examine the use of locally abundant kelp as a feed option for sea urchin gonad enhancement, a 34-week experiment was carried out during which we maintained groups of green sea urchins from southeastern Newfoundland in flow-through tanks at ambient sea temperature and fed ad libitum with three locally abundant kelp diets: (1) kelp combo (Alaria esculenta and Laminaria digitata); (2) L. digitata; and (3) Agarum clathratum. Gonadosomatic index (GSI), gonad colour and gonad texture were assessed after 12 and 34 wk of feeding, and gonad taste after 34 wk. Feeding sea urchins a kelp combo or L. digitata resulted in the highest GSI and best quality gonads at 34 wk, however only L. digitata yielded market-quality roe at 12 wk. Although GSI was higher after 34 wk, gonad quality did not improve with the longer feeding duration and therefore results suggest that 12 wk or fewer may be enough to produce market-quality roe, therefore potentially lowering production costs. Collectively, results suggest that green sea urchins fed locally abundant and easily accessible kelp species produce large volumes of high-quality roe, however, determining the best diet to further improve roe colour and texture requires further research.

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