Scallop dredges are nets with heavy-duty frames made of metal that are pulled over seabed.
They can cause damage to ecosystems in the ocean, with organisms on and below the seafloor being regularly disrupted.
In consequence, scallop dredging was banned in ScotlandThe marine protected areas of the United States.
A modification to a gear that lifts steel bags for catching scallops may reduce the damage during dredging.
ScientistsHeriot-Watt University’s Low Impact Scallop Innovation Gear program fitted “skids”, which were attached to the bottoms spring-toothed scallop-dredges. The skids were then monitored during trials in commercial scallop fisheries throughout Scotland and Wales.
They discovered that the skid, which lifts the bags of metal 10cm above the seabed, reduced the environmental damage to bottom-dwelling animals and fauna.
Research also revealed that a slight modification to the gear could have an average 15% increase in the catch of king scallops.
Scientists found that bycatch, which refers to fish or other animals fishermen don’t want such as starfish, crabs, and scallops, is more common than previously caught.
They suggested further modifications to this kit, such as the increase in size of the metal rings or the implementation skids, could reduce this bycatch.
The added weight of the metal skids meant that the boats were heavier than usual. This led to commercial fisheries closely monitoring the amount fuel consumed by each expedition.
They reported no differences between the two types of dredge, probably due to the reduction of drag during travel.
Scientists claim that using the metal skids can help lower the Co2 emissions caused by scallop dredging, provided an alternative material to steel was used for the construction of the bags.
The study was conducted by Dr Marija Sciberras from Heriot-Watt University as an assistant professor in fisheries.
She stated that adopting technical gear modifications, such as the skid-dredges, would be a “big step forward in the evolution and sustainability of sustainable management and lower impact scallop dredging”.
She stated that skid-dredges were a promising way to develop more environmentally friendly fishing gear that is also financially profitable for the industry. This would yield a higher quantity of scallops as well as reducing the replacement cost of belly bags that are damaged by excessive wear and tear.
Michel Kaiser, co-author of the paper and a professor in fisheries conservation, stated that the study shows that “simple, practical modifications can have significant potential to reduce impacts on target stocks as well as the environment in scallop dredging sectors”.
He said, “But, to be truly efficient, potential technical interventions like these must be considered alongside effective fisheries regulation systems that promote harvest efficiency and appropriate control at sea.”
The UK Seafood Innovation Fund funded the project with 250,000. It was administered and managed by the Centre for Environment, Fisheries and Aquaculture Science for Department for Environment, Food and Rural Affairs.
The program encourages innovative and sustainable ideas that promote seafood security and new partnerships in the technology and seafood sectors.
