6.1 Review: Dredging and sponges

Description

Marine filter feeders are important components of benthic environments providing a range of critical ecological functions including habitat provision, filtration of large quantities of water and consolidation/erosion of sediments and hard substrates. To inform future field- and laboratory-based research on the environmental effects of capital and maintenance dredging on filter feeders, a detailed review of available literature was undertaken. Over 900 peer-reviewed, journal and grey literature articles, technical reports and student theses containing information on the relationship between filter feeders and sediments were examined.

Although the primary focus of most studies was not on the environmental effects of dredging, the literature synthesis provided useful information for impact prediction and monitoring and management purposes. This review generated an enhanced understanding of shorter-term physiological and longer-term ecological responses of filter feeders to sediment and mechanical effects of dredging gear, and has identified physiological and ecological indicators for use in future work. Given the size of the topic, and given their significance in northern Australia waters, the review concentrated on sponges.

Aims

To extract and summarise information from peer-reviewed and grey literature in the context of dredging-related sediment stress on filter feeders, and to assist in future environmental impact assessments (e.g. Duinker & Greig 2007). Information presented includes some understanding on how filter feeders and sediments interact under normal, natural conditions (Schönberg 2015), but also how they will potentially recover after damage.