There's something fishy about seagrass
27 October 2014
If you’ve only ever thought of seagrass as that smelly, brown stuff that ends up on the beach, it’s time to think again. Seagrass meadows deliver a range of important services. They stabilise sediment, cycle nutrients, capture and store carbon, as well as provide habitat for a broad range of fish and invertebrate species. They are also important nursery areas for the eggs, larvae and juveniles of many species that are commercially and recreationally valuable, such as King George whiting and scallops.
Recently, the two dominant species of seagrass that form meadows throughout Nepean Bay have been assessed as ‘Vulnerable’ and ‘Near Threatened’ under IUCN (International Union for the Conservation of Nature) Red List criteria. This prompted Natural Resources Kangaroo Island to investigate the relationship between seagrass and fish species that depend on them, so that potential flow-on effects from seagrass loss could be better understood. To do this, the coast and marine team have spent the last six months ‘fishing’!
Baited Remote Underwater Video Systems (BRUVS) were used for the project. These consist basically of a camera strapped to a bait basket of pilchards, which attracts the fish. BRUVS have become a common tool for observing and recording fish as they enable passive, non-destructive monitoring.
Monitoring took place at eight locations around Nepean Bay, including Pelican Lagoon and Bay of Shoals, and so far has recorded almost 3000 individual fish from 55 species.
These species included three species of shark, five species of rays, 11 species of leatherjacket, including the rare Bluefin leatherjacket (Thamnaconus degeni) and three species of Sygnathid (pipefish and seadragons). Island Beach was the most diverse location, recording 25 species in total. The greatest abundance of fish was recorded at South Spit (359 individuals).
Little rock whiting (Neoodax balteatus), Tommy rough (Arripis georgianus) and King George whiting (Sillaginodes punctata) were the most frequently encountered species, recorded at every location. Little rock whiting were also the most abundant individual species.
Monitoring is ongoing and If you would like to know more about this project please contact us.