Seaweed farming, robot-style

November 6, 2017

green remote underwater vehicle on workshop floor The remotely operated vehicle is tethered to the onboard controls.

This fall Alaska Sea Grant’s Gary Freitag has been using an underwater robot with a special arm he modified to grab spore-bearing seaweed blades.

Collecting blades ready to release their spores is a key step in producing “seed” for seaweed farming.

Seaweed cultivation in Alaska is in its infancy but it’s a multibillion dollar global industry that’s growing. Experts say Alaska’s cold clean waters and many miles of shoreline are excellent for farming, and state residents are beginning to get involved, starting new businesses and expanding existing ones.

Gary Freitag

To help move the industry forward, Freitag is using a remotely operated vehicle (ROV,) which he controls from a dock or boat.

Early attempts at gathering kelp blades proved tricky.

“The ROV manipulator arm did not have enough surface area to grab kelp blades, it just tore them apart,” he said.

Freitag attached flat surfaces to the grippers, and it worked. The ROV was able to bring back big pieces of spore-bearing kelp.

The blades are brought to the OceansAlaska Marine Science Center lab near Ketchikan. The spores will germinate and continue the reproductive process. The resulting young “seed” plants are attached to strings that are wrapped around ropes and submerged, to grow into blades that are harvestable in spring for the market.

The modified robot is one of many Alaska Sea Grant Marine Advisory projects that have benefited from Freitag’s mechanical skills. An underwater time-lapse camera he set up under a dock in 2015 continues to monitor for invasive species, and he has built and set up temporary laboratories for visiting scientists looking for invasives.

For more on Alaska seaweed farming, check out our seaweed farming publication, seaweed webinar, and research project to enhance the seaweed industry in Alaska.

— By Sue Keller

Alaska Sea Grant is a statewide marine research, education, and outreach program, and is a partnership between the University of Alaska Fairbanks and the National Oceanic and Atmospheric Administration. Alaska Sea Grant Marine Advisory Program agents provide assistance that helps Alaskans wisely use, conserve, and enjoy marine and coastal resources.