How biodiverse are Kangaroo Island seagrass meadows?
Prior to 2005, little was known about the faunal assemblages associated with seagrass meadows on KI. It was not known what, if any, effect seagrass decline may have had on marine diversity in these systems. During 2005 and 2006 this knowledge gap was addressed when baseline data on seagrass faunal communities was recorded from sites around the island using a small roller beam trawl. A total of 157 species were recorded comprising 87 species of invertebrates and 70 species of fish. There were significant differences in the composition of faunal communities between sampling locations. The details of this survey can be found here.
This study provided a first insight into the infauna (animals found in seagrass) assemblage of seagrass meadows on KI. To complement this study and further expand our understanding of the more mobile fish fauna which utilise seagrass meadows a baited underwater video systems (BRUVS) project was initiated in 2014. BRUVS attract fish and invertebrates to a bait source, in this case crushed pilchards, where they can be visually recorded. This technique is replicated within each site and between years to provide an indication of diversity and abundance of species which associate with a particular habitat type, in this case seagrass meadows.
BRUVS have been used to assess seagrass meadows throughout Nepean Bay, and initial results have identified 66 species of fish that use seagrass meadows as shelter and/or foraging habitats. 12 of the species recorded are of commercial and recreational importance and include King George whiting (Sillaginodes punctata), Snapper (Pagrus auratus) and Gummy shark (Mustelus antarcticus). Three protected species of syngnathid (Seahorses, sea-dragons and pipefish) were also recorded. On-going monitoring of these communities will be used to identify changes over time and determine the role healthy seagrass meadows play in the life cycle of these species.