Uncovering habitats using video-based, cost-effective habitat mapping

Effective estuarine management requires a detailed understanding of habitats; however, data on the extent and diversity of habitats are often limited. Here, we demonstrate how a cost-effective towed-video technique can be used... [ view full abstract ]

Effective estuarine management requires a detailed understanding of habitats; however, data on the extent and diversity of habitats are often limited. Here, we demonstrate how a cost-effective towed-video technique can be used to generate a detailed map of deep structure-forming benthic habitats within a large estuarine embayment (Port Stephens), and to develop a new estuarine habitat classification system.
Towed video transects with a combined length of 130 km were conducted, to depths of 40 m, using a boat based deployment system. Transects were analysed to produce a habitat classification system based on the National Intertidal Subtidal Benthic Habitat Classification Scheme, and to produce a map covering an area of more than 50 square kilometers.
We determined that ten distinct habitat types occurred within the embayment: three habitats dominated by seagrass species; two habitats dominated by filter feeders; three habitats dominated by macroalgae; and two habitats with minimal benthic cover. Extensive previously undocumented areas of macroalgal and sponge dominated habitats were identified. In addition, valuable information was obtained on changes in the distribution of the rare Dendronephthya australis soft coral habitat, which is only known to occur in high abundance within Port Stephens.
Overall, our study demonstrated that detailed mapping of deeper estuarine habitats can be done in a very cost-effective manner using towed video. The methodology developed during the study generated much-needed, robust data on habitat types and their extent, and will directly inform the review of Port Stephens-Great Lakes Marine Park’s zoning arrangements. It clearly has potential for wider application in similar estuarine systems elsewhere.