Tottori Prefecture, in western Japan, is home to Sakai-Minato Salmon or coho salmon farmed in the Sea of Japan off the town of Sakai Minato.
Growing up with lean and firm meat, the salmon here are killed while still alive to slow down postmortem rigidity, before being shipped to regions across Japan for sashimi and sushi use. The fish are raised below a mountainous area, and farmed at sea farming cages for four to five months from the end of November, while harvesting starts at the beginning of April when the fish reach around 1-3 kg. The farming business was commercialized by 2014 by Nippon Suisan Kaisha, or Nissui, after a two-year feasibility study.
This salmon farming business is now playing a role in the development of new technology with Nissui's new auto-feeding robots that are able to deliver the right amount of feed to maintain growth of the farmed fish, even when weather conditions are bad. The robots also prevent any excess feed from generating waste and polluting the sea.
According to Nissui, a huge amount of manpower is required to prevent excessive feeding because staff must be employed to monitor each fish cage manually and gauge the fish's appetite based on the amount of feed that has been consumed. When it comes to fish farms out in the open sea, there is only a limited amount of time for feeding, and feeding vessels are sometimes unable to reach offshore cages, for example if seas are rough.
To address these problems, Nissui's robotic feeders can supply feed on a fixed schedule, and also contain a feed-demand sensor that can tell when the fish strike fake bait instead. Based on the results obtained, the amount of feed dispensed by the robotic feeders is adjusted, helping to reduce the waste of leftover feed, improve efficiency and minimize any effects on the marine environment.
The auto-feeding robots also contain fake bait that the fish can pull on. Depending on the number of times this occurs, the robots are able to measure appetite and optimize the feed amount accordingly.
Appetite sensors, underwater cameras and sensors that measure dissolved oxygen and water temperature have also been created, making it possible to check information on personal computers or cell phones.
Meanwhile, other companies that aren't directly connected to aquaculture are also playing a role in the field. Mobile phone operator DoCoMo is part of a project to develop a water temperature observation Information and Communication Technology (ICT) buoy that can measure seawater temperatures at oyster and seaweed farms in the Tohoku region, where damage from the March 11th, 2011 earthquake and tsunami was particularly severe for aquaculture farms along the coast.
Working with two other companies, S-Vans and Andex, DoCoMo's aim is to improve the productivity of oyster and seaweed farms affected by the March 11th disaster, and help them to produce high quality products. Eight buoys have been placed at offshore farms off Higashi Matsushima city in Miyagi Prefecture. Working at a depth of 1.5 - 2m, the buoys measure water temperature every hour, while data is accumulated onto a cloud server. The buoys contain communication features and a sensor, and link directly to a smartphone and tablet app, which provides information such as water temperature readings that are updated on the hour. It is hoped that the data gathered will be used to improve and stabilize the area's oyster and seaweed production and that further research will focus on to what extent product quality can improve.
DoCoMo is providing a cloud server that can gather data taken from the buoys' communication module and sensor, S-Vans has developed and manufactured the buoys and Andex has been working on the smartphone and tablet app. The three companies intend to share and develop their know-how with other fish farms across Japan, and add more sensors that can measure more parameters such as wind direction, wind speed, wave height and weather-related information so farmers will be able to raise and harvest oysters and seaweed at the correct time of year. Tests on the current buoys began in March 2016 and are scheduled to continue until the end of March 2017.
It is believed that robots and other technology could help maximize productivity in fish farming and aquaculture, in light of Japan's limited land and human resources. Tech-oriented approaches such as these could also connect various people and companies across the world via the Internet, and create new opportunities in areas such as funding or new forms of Japanese aquaculture.
