The green sea urchin Strongylocentrotus droebachiensis is present in large quantities along the coast of Norway although they are generally of very low quality. Sea urchin gonads are prized seafood in many parts of the world and market demand is high so there is intensive interest in harvesting and enhancement of wild sea urchins. T he formulation of the enhancement feed affects growth, quality characteristics, and biochemical composition of sea urchin gonads. The gonads will also be affected by season (the time of the year they are harvested) and by the harvesting location. It is important to gain knowledge on how these parameters influence the biochemical composition of the sea urchin roe when collected from the wild as well as when it is enhanced.
In this study the nutritional composition in gonads from both wild and enhanced (fed) sea urchin was characterized. The sea urchins were harvested at 4 different locations during two seasons (summer and winter). The collected sea urchins were fed a formulated feed for a duration of 9 weeks. The effects on the biochemical analysis of the sea urchin roe depending on season, harvesting location and enhancement were compared to that of wild urchins collected at the same sampling time, from the same site. The gonadal index (GI) varied between the different harvesting sites and the seasons. All the enhanced gonads contained a favourable fatty acid composition with a higher content of the marine n-3 polyunsaturated fatty acids (PUFA) and eicosapentaenoic acid (EPA: C20: 5n-3) compared to n-6 PUFA. In enhanced sea urchins, the content of bitter AA was higher compared to wild sea urchins. Enhanced sea urchin roe appeared to have a significantly lower level of both Iodine and Arsenic compared to wild sea urchin roe in the current study. There were very low levels of Cadmium in the wild sea urchin samples, but levels were undetectable in the enhanced samples and Lead and Mercury were undetectable in all samples regardless of treatment.
Additional studies showed the composition and variation in the nutrient content of sea urchin biomass collected from the wild. These offer some insights into possible byproducts from the sea urchin industry.
The results of these studies show that sea urchin gonad enhancement is an effective way to produce seafood with a favorable nutritional profile, including a relatively high proportion of marine n-3 PUFA such as EPA. Additionally, the bioproducts of sea urchin fisheries and enhancement (or raw product that is not suitable for enhancement) has potential for commercial use.