Blue Remediation (RD125)

Project Outcome:

Over the one-year in-situ trial, Blue Remediation effectively demonstrated its innovative concept of employing sea cucumbers’ bioremediation capabilities to consume organic matter discharged by salmon farms. The project revealed: 

1. A 75-100% survival rate for sea cucumbers in cages under fish pens (and other deposit feeders and filter feeders were also attracted). 
2. Healthy growth of sea cucumbers, similar to those located in control zones. 
3. A 16-20% reduction in organic matter (OM) in sediments where sea cucumbers were present compared to cages without them. 
4. A 10-18% increase in oxygen levels in the top 2cm of water above the benthos in cages containing sea cucumbers. 
5. A likely effect of sea cucumbers to promote higher benthic infaunal biodiversity and contribute to maintaining biodiversity levels. 

Furthermore, Blue Remediation’s numerical model reproducing Holothuria forskali’s physiology (including temperature and body size influences) has been validated. The model precisely predicted sea cucumber growth at different stages of the in-situ trial. 

When applied to estimating the amount of organic matter removed by sea cucumbers, the model indicated a lower Particulate organic matter (POM) removal (0.4-9% depending on densities) than the observed 16-20% decrease in OM. This difference may stem from the presence of other species (which the current model does not account for) that contributed to the POM removal. Future refinements should consider these species for a comprehensive benthic impact assessment.  

Our next step is to develop an ergonomic user interface to enable farmers to easily utilize the model and effectively predict and manage their benthic impact.