Shellfish
BY NICKI HOLMYARD
The clean-up crew Sea cucumbers could help keep the seabed free of organic waste from aquaculture
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group of researchers is inves�ga�ng whether sea cucumbers can help to minimise the environmental impacts of fish farming. They recently completed a feasibility study to assess how well the creatures perform under laboratory condi�ons, and hope that their posi�ve results will allow them to undertake further research. The feasibility study was undertaken by Blue Remedia�on, a company set up by four PhD students from the University of Strathclyde and Heriot-Wa� University. Their research was assisted by the UK Seafood Innova�on Fund, with support from the Sustainable Aquaculture Innova�on Centre (SAIC). Blue Remedia�on’s founders – friends Melinda Choua, Ana Rodriguez, Soizic Garnier and Marta Pon� – hit upon the idea of using sea cucumbers to process salmon aquaculture waste in the autumn of 2019. “We ini�ally thought about a much wider project, using sea cucumbers as part of an integrated mul�-trophic aquaculture (IMTA) project, then applied for a place on a mentoring programme led by Women in Sco�sh Aquaculture (WiSA) in January 2020. This helped us to narrow down and formulate our project idea,” explained Pon�. The project aimed to be a star�ng point for reconciling fish produc�on and environmental conserva�on. Bioremedia�on, the process of using living organisms to remove pollutants and toxins, is already commonly used in agriculture, par�cularly in Asia and China, to restore polluted soil. However, it is new to aquaculture in Europe. Wrasse and lumpfish are already in use as cleaner fish, helping to keep
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down sea lice numbers, and sea urchins have been trialled in the past to graze in salmon cages. Sea cucumbers, which are from the same family as sea urchins and are naturally found in Sco�sh waters, could help deal with deposits of uneaten food and fish faeces on the seabed. There are more than 1,250 known species of sea cucumbers, which are basically a diges�ve tract with a hole at either end, housed in an oblong body that resembles a fat cucumber. Found on the seabed worldwide, they range widely in size from size from around two cen�metres to nearly two metres. These creatures move around by constantly changing the water pressure in the rows of feet that run the length of the bodies, making them expand and contract. As they move, sea cucumbers ingest the seafloor, breaking it down into small fragments internally, then excrete it back out again. In doing so, they play an important environmental role by removing excess organic ma�er from the sediment. The goal of Blue Remedia�on’s study was to ascertain whether it would be feasible to offer farmers a sustainable alterna�ve to reduce their seabed impact, which is a factor that currently limits fish produc�on. The foursome reasoned that using a natural method to improve the condi�on of the seabed would allow salmon farmers to increase the allowable amount of fish biomass Above and left: Sea in their cages. cucumber Melinda Choua explained that WISA had been a huge accelerator in helping the team to get the project off the ground, and invaluable in introducing them to Mowi, which became their industrial partner, supplying sediment from their Loch Leven site. Salmon faeces were provided by the University of S�rling’s Ins�tute of Aquaculture, so that the researchers could mimic the natural ecosystem. “WISA also provided us with a mentor, Michael Mason, who put us in touch with all the different
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12/04/2021 16:00:30
