Inside New Zealand’s kina, the country’s indigenous sea urchin, is a delicacy that can fetch as much as NZ$500 a kilogram in Japan.
Each year the Japanese consume 60,000 tons of roe from sea urchin in sushi and import about 10,000 tons. But local scientists and industry think that New Zealand’s sea urchins could contribute to sating the Japanese appetite for roe.
“What you see in Japan is basically the top 1-5 per cent they cream and that’s why they are paying a premium price,” says Chris Woods, an aquaculture research scientist at the National Institute of Water and Atmospheric Research.
Roe — actually the gonads of the sea urchin — can range from dark brown to the soft yellow that is preferred in Japan. The size of the roe masses — Japanese chefs prefer them to be 3 1/2 to 4 centimeter’s across — can also vary. New Zealand’s sea urchins turn out an eclectic selection of roe: “You normally get a whole range of colors, size, and taste,” says Woods.
And the amount available from the wild is scant — just 675 tons of kina are caught commercially from New Zealand waters and most of that quota is sold on the domestic market. And since 1992 the Ministry of Fisheries has had a moratorium on the issue of permits to commercially harvest kina.
So NIWA researchers are aiming to figure out how best to grow bigger quantities of New Zealand sea urchins — perhaps in a land-based operation or in kina marine farms — and to ensure the roe is optimum for the Japanese market.
At present, says Chris Woods, New Zealand’s waters produce of roe that the Japanese market wants, just not consistently. “They can come out a good colour and a good taste. Unfortunately, it varies according to different types of year and different locations.”
“They will be from the same area, same food, so what are the reasons why one is bad and one is good?”
One of the variables that the NIWA team hopes to track down is diet. The aim is to develop special diets which will increase the yield and improve the quality of roe from harvested kina. Already Woods says that they are starting to see differences — including speedier growth — between the different diets they try.
NIWA is also looking at aspects of the husbandry of kina — whether they will grow better in sea cages or on land; whether they grow faster at different times of the year, or if they prefer to grow in flowing or still water. At present, New Zealand’s sea urchins are found in waters less than 10 meters deep and are harvested by breath-hold diving.
“There’s a whole range of different variables that we are trying to get a handle on basically,” explains Woods.
But not all the kina in New Zealand necessarily has to be sold in the finicky Japanese market, says Wood. There are strong markets in other places such as Australia and Taiwan and in New Zealand. “The stuff which is not what they (Japanese consumers) regard as premium is often perfectly acceptable in our domestic market,” Woods says.
To ensure the end product is just right, NIWA has the help of Nippon Suisan Kaisha of Japan, who are taste-testing he resulting roe from each batch of trials, and the Sealord Group who are providing the base ingredient — fish byproducts — for the kina diets.