Data loading...

Japanese Build Huge Indoor Aquarium To Collect Bluefin Eggs

Video monitors will allow researchers to keep an eye on the bluefin tuna in the aquarium

An indoor aquarium was completed here on July 3 for the collection of fertilized bluefin tuna eggs, a possible big step toward completing the farming cycle for the prized fish.

The facility was completed at the Seikai National Fisheries Research Institute of the Fisheries Research Agency.

The fry born from the collected eggs will be raised in net pens.

The tuna is now farmed in outdoor net pens, but changes in water temperature and the amount of sunlight directly affect the fish, making it difficult for stable fertilized egg collection.

In addition, during the process of growing into fry, the eggs and larvae are often eaten by other fish or die when caught in the nets at the pens.

That has led many tuna farmers to catch wild fry and raise them in the farms. But such measures have raised concerns about a depletion of the overall tuna stock.

Water temperatures and the amount of sunlight can be adjusted in the indoor aquarium.

“I believe expectations are high for what will be the first of its kind experiment,” said Keiichi Mushiake, head of the Research Center for Tuna Aquaculture. “We hope to establish stable farming technology that can meet those expectations.”

Bluefin tuna produce the fatty “toro” that is a popular ingredient at sushi restaurants.

The facility has two concrete aquariums each capable of holding 1,880 tons of water. Each cylindrical tank has a diameter of 20 meters and depth of 6 meters.

Cameras trained on the aquariums will allow workers to monitor the bluefin tuna. Water in the tanks can be circulated to adjust the temperature, and researchers hope to unravel the process through which fertilized eggs are produced.

The tanks already hold 114 two-year-old bluefin tuna that were raised in a net pen off the coast of Amami-Oshima island in Kagoshima Prefecture. It takes four to five years for bluefin tuna to reach maturity, meaning researchers will seek to begin egg collection in about two years.