Scallop potting with lights: A novel, low impact method for catching scallops
Scientists at Fishtek Marine have documented for the first time that scallops can be attracted into static fishing gear using LED lights. With the recent publication of our scientific paper describing these novel findings we present the fishing industry with the opportunity for the development of a new, low impact method of fishing for scallops.
Wild caught scallops are traditionally caught using dredges and trawls or hand sourced by divers. The UK hand-dived scallop fishery represents <2% of total landed weight nationally whereas dredge caught scallops account for 95% of scallop landings (Cappell et al., 2018).
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.
REDUCED ENVIRONMENTAL IMPACTS
Static fishing gear is far less damaging to benthic habitats than mobile demersal gear with benthic communities in areas open only to static gear being richer and more diverse that those areas subject to towed fishing gear (dredges and trawls). Potting is considered a ‘more responsible’ fishing method due to its limited impact on habitats, energy cost per/kg fish caught and levels of non- commercial bycatch.
Scallop potting provides fishers with an opportunity to augment their existing crustacean catches with scallops rather than targeting scallops as an entirely new stand – alone fishery ensuring the fishery remains sustainable and low-impact.
Scallop potting if developed appropriately offers inshore fishers the opportunity to engage in a scallop fishery with little financial outlay or risk. It is scalable and easy for current fishers to adapt their existing gear to augment their catches with premium, high value scallops. Pot – caught scallops are likely to be comparable to the price of hand – dived scallops due to their similar environmental and quality credentials.
Scallop potting could provide fishers with access to new ground, as fishing with illuminated pots could allow fishers to catch scallops inside some Marine Protected Areas and around Offshore Wind Farms where mobile fishing gear is no longer allowed.
ENVIRONMENTAL SOCIAL AND CORPORATE GOVERNANCE (ESG) BENEFITS
The UK government highlighted shellfish fishing using trawls and one of the main pressures preventing the achievement of Good Environmental Status (GES) of European marine waters. For European retail corporations looking to achieve a high ESG score seafood procurement will have to shift away from damaging fishing methods and move towards lower impact forms of fishing such as scallop potting.
Novel scallop behaviour
The process by which scallops are attracted to illuminated pots is not fully understood, however, it is likely that the motivation is visual. Scallops possess multiple image-forming eyes which are sensitive to both light and motion. We theorize that their movement into the illuminated pots is either to move to preferred feeding areas where more prey is present at the light source or, to move to a relatively illuminated place for protection from predators.
Following the success of this study we have secured further funding to take this potential scallop potting fishery further. Over the next 8 months we are going to be optimising the trap and PotLight designs to ensure that scallops can be harvested effectively without impacting crustacean catches or effecting fishing operations. Sea-trials with these new trap and light designs will take place in different fishing areas around the UK with high-density scallops’ beds. The focus of these sea trials will investigate the following factors: light intensity, light colour, duty cycle and trap efficiency. By the end of this work, we aim to provide a method to coastal fishers wishing to augment their crustacean catches with high-value scallops.
Click on the button for access to the full press release annoucing the launch of this new paper. For media enquiries please contact those listed in the press release.