CUCUMBERS IN COOLER WATERS

IN April 2021, Fish Farmer reported on a feasibility study which was also looking at sea cucumbers and their potential for dealing with organic waste. Blue Remediation, a company set up by four PhD students from the University of Strathclyde and Heriot-Watt University, won funding from the UK Seafood Innovation Fund (SIF) and the Sustainable Aquaculture Innovation Centre (SAIC) to assess the potential for a full-scale study.

Findings from the feasibility study were positive and Blue Remediation began an 18-month project in Scotland, which is due to complete in February 2023. There are three components to the research: a lab element in October and November 2021; deployment in cages – which the researchers had to design and build – below a fish farm for one year, starting in March 2022; and a modelling exercise based on the data gathered.

The study is still ongoing, but so far Blue Remediation’s Scottish sea cucumbers appear to be thriving just as well as the Mediterranean Holothuria.

Marta Ponti, one of the co-founders of Blue Remediation, says: “Our biggest challenge was predators – we weren’t expecting so many!” Crabs and starfish apparently found the caged sea cucumbers too good to pass up. The sea cucumbers themselves also turned out to be skilled escape artists, although even those that did break free from their enclosures mostly did not stray far from the salmon pens.

Ponti’s colleague Melinda Choua says: “We still have to collect and model the data, but we found that while the fish were there in the salmon pens, the sea cucumbers were gaining weight. Then the fish were harvested and when there were no fish, the cucumbers lost some weight. Now there are fish in the salmon pens again and we can compare results.”

The team expects to be able to publish results once the modelling is complete.