Some general activities might risk spreading INNS. These include minor works, repairs, maintenance and construction that would not necessarily need a marine licence. See the Natural Resources Wales website for more information. 

The movement of material and equipment on or off a site risks transferring INNS which could be attached to surfaces, trapped in any water-retaining features/crevices (including in porous materials like concrete), living in sediments or among other species. If the material or equipment is not thoroughly cleaned and dried before moving on or off the site, any INNS that are present would also be moved on or off the site. 

Equipment, parts or materials that have been in water for long periods of time can build up biofouling which can be dislodged into the water during maintenance, cleaning or replacement – allowing INNS to spread to new areas. 

The below best practice guidance is for those planning or undertaking minor work at a site. 

Activity: Cleaning, maintenance or removal of structures / items in the water 

✅  Inspect the structures before disturbing them.  

✅  If there is fouling, bring the structure out of the water and clean it before carrying out any additional work, retain any material that comes off the item and dispose of it on land. 

Activity: Bringing new infrastructure / equipment and material on site  

✅  Ensure it is fully clean and dry before it is used. 

✅  If unclean when it arrives, take to a suitable location for cleaning, this should be a contained area of hard-standing with appropriate drainage. Wastewater and waste material should be collected and disposed of in a biosecure way to prevent INNS (including larvae, fragments, etc.) re-entering the environment (e.g. water tanks and biological waste bins). 

✅  If possible, check the source of the item(s) and understand what INNS are present at that site. 

Activity: General operational good practice for infrastructure 

✅  Where practical, remove man-made structures from the water when they are not in use.  

✅  If unable to remove when not in use, drop moorings to the seabed to smother fouling (in muddy sediments) or prevent new growth.  

✅  Identify opportunities to dry out equipment or infrastructure as often as possible, e.g., drying room/area for kit, PPE etc.  

✅  Make the most of any natural flows of freshwater into your site. Expose INNS to fresh water through immersion or wash down.