Dredges are the most common fishing method used with the dredge design varying between countries. UK scallop dredges are considered to be the most damaging dredge design due to the penetrative nature of a dredge which can cause considerable physical disturbance to the seabed. Interaction between dredges and the seabed resulting in damage to sensitive marine habitats have been widely documented. Hand dived scallops whilst having minimal impact on the seabed result in a low number of landings due to physical limitations such as water depth, dive time, weather conditions and ground coverage. In order to protect sensitive marine species and habitats limited attempts have been made to mitigate dredging impacts by modifying the design of the dredge however these have been yet to show any improvement.
In 2019, a commercial crab fisherman from Cornwall carried out a one – month trial using a single white PotLight inside a standard commercial pot. He was asked to note down any effects he saw on his catches, no notable difference in his crustacean catches were reported but he had seen a large number of scallops in the illuminated pots. This was a great surprise, usually he caught an average of five scallops per year with his standard gear (approximately 35,000 pots) whereas when using the PotLight he saw 10 scallops per 50 pots! This anecdotal evidence allowed us to apply for funding from the Seafood Innovation Fund to carry out a feasibility study to investigate the potential for the use of lights to attract scallops into pots.
During a three-month study off the Cornish coast, the effect of using light in a range of pot designs on scallop, brown crab, lobster, spider crab and crawfish catches was assessed. Retained catch species with no market value or those not meeting the fishing management requirements were discarded. All pot designs with lights retained scallops with a total of 518 scallops recorded and 24 scallops being retained in a single pot! This study has documented for the first time this novel scallop behaviour and has shown that simple and inexpensive modifications to existing crustacean pots present fishers and managers with a wide range of environmental and industry opportunities. The results from the feasibility study have now been published and the paper can be read in full here.