Large floats stacked on a quay, marked with shells and grime

Fishing and aquaculture

Fishing and aquaculture gear that shellfish and seaweed find harder to grip.

We hold back the shellfish and seaweed that grow on fishing and aquaculture gear by working on its surface. In research led by Professor Kuroda, our technical supervisor, no shellfish or algae had settled on a treated float a year after it was put in the sea, and rope used for nori nets showed a strong effect against settlement. We are continuing our own rope trials in the sea at Kure, and are also considering oyster rafts and similar gear.

For fishers, aquaculture businesses, fishing cooperatives, local governments and fishing gear makers

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The problem

When shellfish and seaweed grow on floats, rope and nets, the gear gets heavier, and cleaning or replacing it takes time and labour. In oyster farming, barnacles settle on the growing oysters too. Oyster farmers told us that about 40% of the oysters that barnacles settle on die, and as many as 90% in some places.

Ropes pulled from the sea, with growth on them

What we do

We treat the surface of floats, rope, nets and other gear, bonding a fluorine-based antifouling agent to it so shellfish and seaweed struggle to grip. We use no copper, silver or other biocides. For IKAK, the oyster-raft beacon we are developing separately from surface treatment, we never publish where boats or fishers have been.

How the treatment works

Where things stand, and what to know

  • We start with items about the size of a football, which fit our current equipment.

Stage and evidence

Each claim carries its own stage, and who confirmed it where that is on record. Results of Professor Kuroda’s research are shown apart from our own trials.

Floats and buoys

Treating the surface of the floats and buoys used in fishing and aquaculture so shellfish and seaweed take hold less readily. The evidence comes from a float tested in the sea in Professor Kuroda’s research.

Where the technology comes from: Kuroda’s research

Published results of KAKEN grant 22K04725, led by Professor Kuroda, our technical supervisor. We list them apart from our own trials.

  • Stage: Proven, KAKEN grant (Kuroda’s research)

    In the published report of KAKEN grant 22K04725, led by Professor Kuroda, our technical supervisor, a small polyethylene float (about 150 mm across) with a fluorine-based agent fixed to its surface had no shellfish or algae settled on it a year after it was put in the sea, while kelp and other seaweed grew thickly on the rope holding it. The research’s sea trials were held in Hakodate, Hokkaido, and elsewhere.

    Source: Published report of KAKEN grant 22K04725

Related uses

Talk to us about “Floats and buoys”
A treated pink float after a year in the sea, with seaweed grown thick on the rope holding it
Professor Kuroda’s research (KAKEN grant 22K04725), a year after the float was put in the sea

Rope

Treating the surface of rope used in fishing, aquaculture and elsewhere so shellfish and seaweed take hold less readily.

  • Stage: Being tested, Our own work

    We are continuing rope trials in the sea at Kure.

Related uses

Talk to us about “Rope”
A wooden raft afloat in clear water
Kure
  • Someone crouching on an oyster raft, taking hold of a rope

Fishing and aquaculture nets

Treating the surface of fishing and aquaculture nets so shellfish and seaweed take hold less readily. The evidence comes from research by Professor Kuroda and Professor Terakado on rope used for nori nets.

Where the technology comes from: Kuroda’s research

Published results of KAKEN grant 22K04725, led by Professor Kuroda, our technical supervisor. We list them apart from our own trials.

  • Stage: Proven, KAKEN grant (Kuroda’s research)

    Rope given the fluorine-based treatment strongly held back settlement in sea trials reported for KAKEN grant 22K04725 (principal investigator: Professor Kensuke Kuroda; co-investigator: Professor Osamu Terakado), using 2 mm vinylon nori-net rope stretched on 50 cm square frames.

    Source: Published report of KAKEN grant 22K04725

Related uses

Talk to us about “Fishing and aquaculture nets”
A fish pen of black netting hung from a wooden frame
Kurahashi Island, Kure

Oyster rafts and baskets, and filters in land-based aquaculture

Using the treatment on aquaculture gear such as oyster rafts and baskets, and on the filters of land-based aquaculture. Barnacles on oyster rafts are the problem our company started from. It is the gear that would be treated, not the oysters themselves.

  • Stage: Concept,

    We are considering holding back barnacles and other growth on gear such as oyster rafts and baskets, and keeping the filters of land-based aquaculture from clogging.

Related uses

Talk to us about “Oyster rafts and baskets, and filters in land-based aquaculture”
Oysters covered in barnacles, in a wire bin
  • Bundles of strung scallop shells stacked on racks
  • A bamboo raft frame brought ashore
  • A bamboo oyster raft on the sea, with lines hanging from it into the water

Ways to work with us

How to read the stages

Stage: Proven,
Results checked at sea or in the field, and on record
Stage: Being tested,
Trials, prototypes or development under way
Stage: Concept,
At the planning stage, including ideas shown as exhibits or prototypes

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