The Challenge Of Harvesting Sea Urchin

Around 50 % of Sea Urchin that are generated in Japan are harvested in the sea areas of Hokkaido. 
 
Consider a top ingredient in Sushi, the tiniest error in treating and handling the uni might scar the shape of the roe, therefore wrecking its value. There is many difficulties in tranporting Uni, one major factor is that it spoils very swiftly. So it is a difficult challenge for many Companies in keeping Uni fresh for consumer palettes.
 
A lot of work goes into handling the delicate Urchin into wooden boxes and is a major factor for its high cost.
 
Many improvements in keeping Uni fresh during transport has help increase the sales of Uni and thus giving access to a larger population.  This has helped increase its popularity across Japan and the world. 
 
Source and Read more @ ajw.asahi.com