Towa Marine Products

Mr. Tatsuya Sakamoto

LED floodlights used to farm flounder

Towa Marine Products, Saiki City, Oita, Japan



Flounder farming facility at Towa Marine Products

This feature talks about the use of LED floodlights for the farming of flounder at Towa Marine Products, located in Saiki City, Oita.

Oita prefecture is located in the northeastern region of Kyushu, an area where the local government is channelling its energy into its fisheries industry. Saiki City faces the Bungo Channel, a strait separating Kyushu from the main island of Japan, and accounts for over 60% of Oita’s fishing industry.

The farming of flounder and yellowtail is particularly prominent in the area with 80% of the prefecture’s production volume coming from Saiki City. The city thrives on its fishing industry, holding the top share across Japan for the farming of flounder.

Towa Marine Products had already been farming flounder; however, this was a new initiative aimed at further promoting the growth of flounder using green LED lighting.

We custom fabricated our LEDSHIGHMAST LLF0011A into a two-module unit fitted with green LEDs for installation in the fish farm.


Mr. Tatsuya Sakamoto

Towa Marine Products

Mr. Tatsuya Sakamoto


Flounder farming facility

We talked to a farm manager at the Towa Marine Products flounder farming facility, Tatsuya Sakamoto about the farming of flounder and our LED floodlight, LEDSHIGHMAST.


First of all, thank you for choosing to use our LED floodlights for the purpose of farming flounder and taking the time out of your busy schedule to talk to us today.

Sakamoto: Thank you for coming all way out to Saiki, Oita.

How long have you been working here?

Sakamoto: I’ve been working here for about 15 years, but I’ve worked in the fisheries industry all my life. I am currently in charge of this farming facility.

So, you are an industry professional! Can you tell me what made you choose to use LED floodlight at the facility?


Sakamoto-san tending to his flounder

Sakamoto: Results from a university study revealed that green light can promote the growth of flounder and sole. Based on this research, the Oita government set about actively introducing this technology and we are also receiving support from the government.

So, the results of this research have been put to use on the front line of industry in this facility! When were the floodlights installed and how are you using them?

Sakamoto: The floodlights were installed in May 2021. We have five fish tanks here and we are using 15 floodlights for each tank. That means we have a total of 75 LED floodlights, which are fitted 180 cm above the water surface.

How long are the green LED lights on for and what kind of results have you seen in terms of growth in the fish?

Sakamoto: The LED floodlights are generally only on during the day. As for results, it used to take 12-14 months to get the juvenile fish to grow to the 1 kg weight required for shipping, but now we can get them to the same weight in just 9-10 months, which means we can ship them out faster. If we compare the breeding of flounder under the lights and those not exposed to light using the same feed for the same period, we can now breed approximately 1.6 times faster.

That is a clear result! Does that mean there has been some change in the way the fish behave under the lights?


Sakamoto: Yes, the fish have become much more active. Flounder generally spend most of their time sitting on the bottom, but they now swim around so much that you would think they were a totally different fish.

I am very happy that the LED lights have had a positive impact on your business. What do you find challenging about fish farming?

Sakamoto: Of course, we needed to make an initial investment to introduce the floodlights; however, LED lights are cheap to run, and because we can now ship the fish out faster, we have been able to reduce labor and power costs. We have achieved cost reductions of approximately 3 million yen/year.

In terms of challenges, the one thing we must be careful about is not letting the fish get sick and killing them. Because we are positioned right in front of the ocean and use water straight from the ocean just 100 meters away, we are also careful about red tides. Thankfully, our fish are all growing healthily this year.


Photo left: Checking for red tide
Photo right: The farming facility is constructed of wood and is very large

Thank you for the opportunity to talk with you today. Take care of yourself and continue to breed big, delicious flounder.

Sakamoto: Thank you. We also offer a flounder marinated in miso online through our group company and a range of fresh local fish at reasonable prices at its restaurant.

Lighting Equipment


LEDSHIGHMAST LLF0011A custom product
(2-module/green LED) 75 units

standard productProduct Image

Product appearing in this project

LLF0011A (custom product)

Jump to standard product product information