SMART (Shark-Management-Alert-in-Real-Time) drumlines are one of the measures currently being tested and trialled as part of the NSW Government's $16M Shark Management Strategy.
The state-of the art technology differs greatly from the operation of traditional drumlines as they are designed and operated to maximise the survival of sharks and other marine animals caught.
SMART drumlines have an anchor and rope, two buoys, and a satellite-linked communications unit which is attached to a trace and baited hook. SMART drumlines are deployed approximately 500 metres offshore away from swimmers and surfers to allow sharks to be intercepted beyond the surf zone. When a shark is hooked, the pressure on the line triggers the communications unit which alerts DPI scientists or contractors via phone call, email, and text message to the presence of an animal on the line. The team then responds immediately to the SMART drumline alert to manage the animal.
SMART drumlines are a valuable research tool. Sharks caught on SMART drumlines can be tagged and released alive, allowing us to collect data about the population of sharks that use NSW coastal environments. This includes their seasonal pattern of movements along the NSW coast. Sharks caught using SMART drumlines and tagged with satellite tags are being detected more than 12 months later, with the longest period between tagging and last detection is 756 days.
As a mitigation measure target sharks, White, Bull and Tiger, caught on the SMART drumlines are relocated approximately 1km offshore and released. Intercepting and catching sharks as they travel along our coastline reduces the chances of an interaction with water users.
Preliminary analysis of satellite tagged sharks suggests that they often head further offshore immediately after release (for the first 24-48 h). So in addition to minimising any immediate threat of an interaction with water users, their movement offshore after release further enhances the value of SMART drumlines as a non-lethal bather protection tool.
Furthermore, when tagged sharks pass within approximately 500m of our network of 21 VR4G listening stations DPI provide alerts to the community via the SharkSmart app (itunes.apple.com) and DPI SharkSmart Twitter account @NSWSharkSmart.
Any non-target animals, i.e. bycatch, is released alive immediately.
The community survey is now closed. Results are currently being analysed and will be presented in mid December.
Trials of SMART drumlines have been undertaken at multiple locations on the NSW North Coast by DPI scientists since December 2015.
Up to 35 SMART drumlines have been deployed daily between Evans Head and Lennox Head (weather and ocean conditions permitting) by Contractors since December 2016 (see table below).
Table 1: Cumulative total of target shark species caught on SMART drumlines since December 2016 at Ballina-Lennox Head and Evans Head. Note, all sharks, except for two White Sharks were released alive; one White Shark died at Ballina-Lennox Head, and one White Shark was found dead on Airforce Beach, Evans Head on 12 May 2017 after being tagged and released on 7 May 201
Table 2: Cumulative total of non-target species caught on SMART drumlines since December 2016 at Ballina-Lennox Head and Evans Head. Notes: the Loggerhead Turtle was tangled in the trace (but not hooked); a Common Blacktip Shark was found dead on the line after an alert at Evans Beach; a Black Marlin was found dead on the line after an alert at Ballina-Lennox Head;
Whaler Shark - unidentified
Shortfin Mako Shark
Common Blacktip Shark
Six month trials using ten SMART Drumlines have been undertaken each of the following locations:
Our DPI Shark Tagging Team is having promising success tagging White, Tiger and Bull sharks using SMART drumline technology while it is also proving effective in catching target species with minimal bycatch and mortality. The initial trials of these SMART drumlines demonstrated their ability to capture sharks and trigger the system with instant alerts.
They have proven to be four-times more effective than mesh nets on the North Coast during our six month trial earlier this year with minimal bycatch of non-target animals.
DPI will continue its research to fine tune this gear for use in Australian conditions. This involves testing different gears (hooks, trace lengths and trace material), bait types to maximise catch rates of target shark species only, and videoing the activity of animals around SMART drumlines before and after capture using underwater cameras.