Divers have hauled 750 kilos of lost fishing nets and related debris from the sea bottom over the past 10 days in an annual clean-up of the area.

The North Sea environmental protection foundations Duik de Noordzee Schoon and Stichting de Noordzee which organise the event, argue that the nets are a great danger to fish, lobsters and crabs which can become ensnared in the netting and die.

Fishing nets are designed to be strong and do not break down in seawater and some could last for 600 years, the organisation said. ‘We have left the North Sea cleaner than we found it,’ said team leader Ben Stiefelhagen. The team found fewer fishing nets but more garbage such as plastic bottles this year.

This was the 12th expedition organised by the foundation since 2011. It has gathered up some 35,000 kilos of fishnets and other debris from the bottom of the sea over the years.

The team, made up of 28 divers who carried out 13 dives, extended its range this year to cover part of the British section of the North Sea around Dogger Bank.