Mechanical lugworm dredgers have been in use in the western part of the Dutch Wadden Sea since about 1975, when four machines were harvesting about 17-20 million lugworms per year. This, combined with 12-16 million dug by hand, represents about 0.75% of the total population of lugworm in the area (Wolff et al. 1981). The first experimental dredging in Britain took place in Essex in 1989, but commercial exploitation of lugworm beds in the UK has not been undertaken. This is because the cost of the licence that would be necessary for the redeposition of dredged sediment under the Food and Environment Protection Act 1985 (FEPA) was so high as to make this activity uneconomic.

Mechanical dredges work at high tide. A barge is anchored over the sand flats on a 250-300 m cable. The barge is very slowly winched towards the anchor and a gully 1 m wide and 40 cm deep is scooped out by the dredge. The sediment is sieved with jets of water through a 1 cm mesh and lugworms removed by hand from the material retained on a conveyor belt inside the barge. Several gullies can be worked on each tide.

Impacts of worm dredging on fauna, habitat and other shore users

Opportunities for mitigating the impacts of worm dredging for bait

References