CONTAINMENT SPECIAL
SARF 054
the base of larger nets. However, damage during deployment is probably less likely on smaller pens, which also allows farmers to be able to inspect the base. Whilst dive inspec- tions do give the opportunity to view the net after deployment and to inspect the base, it is not always easy for a diver to identify small signs of damage across many square metres of net. The important point, however, is that inspections are undertaken before and after certain operations as well as on a routine basis, using whichever method(s) are most ap- propriate for the type of equipment in use. It is recommended that nets are visually inspected in situ prior to being stocked, after every time a net is changed, installed or lifted and at least monthly thereafter. Inspections should be given a high priority by manage- ment – and carried out by staff dedicated to the task with sufficient time to do so, and be properly supervised and recorded.
Waterline protection
Double thickness netting is used by some farmers for either half a metre or a metre
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above and below the waterline on freshwater sites to provide additional protection against predation from otters and mink. However, whilst otters and mink are typically thought to attack these areas of the net, there is con- cern that additional protection here may just encourage them to attack lower down the net – which is less easily inspected. Whilst continu- ing attacks at the waterline are problematic for the farmer, they can be easily identified on a daily basis by farmers and immediately rectified. Usually, traditional net materials are used to provide such double netting, but at least one company has successfully trialled the use of more innovative materials. One freshwater escape incident was caused by mink attacking the base of the net, indicating that waterline protection by itself is not always sufficient pro- tection should predators attack elsewhere. It is recommended that all freshwater cage farmers consider the benefits of additional protection through the use of double netting or similar, 1m or 0.5m above and below the waterline, to help reduce the likelihood of a successful
THIS CAGE IS FITTED WITH A BIRDNET TO KEEP PREDATORS SUCH AS CORMORANTS OUT
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