Review of Mitigation Techniques for Trawling Impacts on Benthic Ecosystems

Trawl induced habitat modifications have been suggested to negatively affect benthic foragers that depend on an intact benthic ecosystem, such as hoiho. Indirect effects are also possible via changes to the structure of the seafloor and the suspension of sediment. The most common mitigation method for these effects have been closures of sensitive areas to trawling.

However, in recent years studies that test modified fishing gear to reduce the effects of trawling on seafloor communities have been emerging, with several showing promising results (e.g. Rose et al. 2010). Bottom trawling uses numerous types of gear designs, sizes, rigging and operational methods.

Therefore, impact on the bottom habitat will differ among the various bottom trawl fisheries, and mitigation techniques will depend on the gear used. This desk-based study aims to review literature on mitigation techniques used to reduce benthic impacts of trawling in various bottom trawl fisheries and make recommendations that are relevant to New Zealand trawl fisheries.

This study may lead on to a project focusing on trialling modified trawl gear in the inshore fleet.