Fisheries Infosite

Environmental Issue


Damage to the sea bed habitat from scallop dredging
Where analysis has been done in the Coromandel scallop fishery, the dredging 'footprint' covers only a small part of most habitat types. However, we have not done this analysis in any other dredge fishery. Dredge fishing is a significant risk to the integrity and productivity of marine ecosystems, particularly where this occurrs on biogenic habitats like bryozoans, mussels and sponges these are important nursary areas for some commercial species). Marine life and productivity of commercial fisheries can also be significantly affected by sediment plumes created by dredging through muds and silts.
Extent of the issue
The northern and Coromandel scallop fisheries have singnificant recreational fishing effort, much of which is taken using dredges. The northern and Coromandel scallop fisheries are also important commercially, as is the South Island's Queen Scallop fishery. Repetative dredging of scallops across all fished grounds will have had a major impact on these places.
Repetative dredging in these fisheries will have substantially modified many areas of seabed habitat.
Current management
Some particularly sensitive seabed habitats at Spirits Bay (Cape Reinga) have already been closed to dredging. A range of dredge restrictions exist in many other parts o New Zealand, inlcuding Marine Reserves and a number of Mataitai Reserves created during the 1980s, 90s and 2000s.
Future management
The government is in the process of developing developing Fisheries Plans for managing the Northern and Coromandel scallop fisheries. These plans will address a range of fisheries issues, including managing the effects of seabed dredging. 
Documents / links
Marine Protected Areas Policy and Implementation Plan, Jake Rice, global analysis - Kaiser 2006.