SMART Drumline Trial
FREQUENTLY ASKED QUESTIONS
WHAT IS A SMART DRUMLINE?
‘SMART’ is an acronym for Shark-Management-Alert-in-Real-Time. A SMART drumline is designed to be non-lethal and to send an alert when a shark has been captured on the line. Anchored to the sea floor, SMART drumlines comprise of two buoys and a satellite-linked GPS communications unit attached to a baited hook.
A triggering magnet is attached to the communications unit and the line. When an animal takes the bait and puts pressure on the line, the magnet is released. This causes the communications unit to transmit its position to the drumline operator, alerting them to the presence of an animal on the line. Once alerted, the drumline operator can immediately respond to tag, relocate and release the animal as required.
The locations of the non-lethal SMART drumlines in the Gracetown trial were based on a vessel attending within 30 minutes of an alert being received.
Who was responsible for the deployment of SMART drumlines?
The Department of Primary Industries and Regional Development (DPIRD) was responsible for implementing the trial and managing the contractor who operated the SMART drumlines.
The appointment of the contractor was subject to a formal tender process in accordance with Government procurement processes.
The contractor received comprehensive training, and regularly had DPIRD staff on board the vessel to ensure compliance with fishing and shark handling guidelines.
During the two-year trial, DPIRD staff were present on approximately 35 per cent of fishing days.
How often were SMART drumlines deployed?
Weather permitting, SMART drumlines were deployed and retrieved each day.
It was the responsibility of the drumline operator to stay in the vicinity of the drumlines, providing the capacity for an immediate response once alerted to the presence of a shark on the line.
During the two-year trial, drumlines were deployed on 465 days. Fishing was prevented on 266 days due to risk weather conditions, where fishing operations held high risk to the safety of the animals and staff.
What were the objectives of the trial?
The Western Australian trial gathered tagged shark movement data which was assessed to determine whether SMART drumlines reduced the risk of shark interactions under local conditions.
The target species for the trial was white sharks, as the majority of fatal and serious shark bites since 2000 in Western Australia have been attributable to white sharks.
The Chief Scientist, Professor Peter Klinken AC, undertook an independent assessment on the effectiveness of SMART drumlines in reducing the risk of shark bite incidents. It was determined that the technology was not effective as a shark mitigation measure in Western Australian conditions.
What tags were used as part of the trial?
All sharks caught during the trial received an identification tag for easy physical identification, to determine if the shark has been caught as part of the trial.
White, tiger and shortfin mako sharks also received:
- External acoustic tags to allow detection by shark monitoring receivers as part of the Shark Monitoring Network and data recording receivers deployed for the term of the trial.
- Pop-up archival transmitting (PAT) tags to collect water depth, temperature and broad scale location data.
Why did we use pop-up archival transmitting tags?
Pop-up archival transmitting (PAT) tags consists of various sensors, a data recorder, a programmable, automatic release mechanism and a transmitter for data retrieval via satellite. PAT tags are positively buoyant and float to the surface at a pre-determined release time and data is then transmitted via satellite.
PAT tags collect data on time of day, light levels, temperature and water depth. This data enables scientists to broadly estimate the shark’s movements from the time a shark is tagged, to the time the tag releases from the shark. The PAT tags for this study also use an accelerometer to detect if a tagged shark keeps swimming after release and so will be used to estimate survival rates following tagging, a critical aspect of the trial. The PAT tags also monitor for constant depth, a state which implies the tag is floating at the surface or sitting on the sea floor. If constant-depth is met the tag will release, indicating animal mortality or tag shedding and transmit its data summaries.
PAT tags are not designed or intended to provide a real-time satellite-track of a shark. Tags that use satellites to determine a shark’s position cannot reliably provide the level of accuracy required for fine-scale tracking as transmission of position is limited to when the shark’s dorsal fin breaks the surface. Such tags would not provide information relevant to the design of the trial.
How far offshore were sharks released?
Where possible all white sharks and tiger sharks three metres or greater in length were relocated one kilometre offshore.
While every attempt was made to relocate these sharks, in some instances contractors were unable to relocate all sharks safely, for example where weather conditions impacted the safety of contractors and welfare of sharks.
During the two-year trial, two white sharks and 37 tiger sharks larger than 3 metres were successfully relocated 1km offshore.
How were tagged shark movements monitored?
Movement of acoustically tagged sharks were monitored via VR2 acoustic receivers on the sea-bed around the perimeter of the trial area. Data stored in the on board memory of the receiver was downloaded.
In addition, acoustically tagged sharks could also be detected by one of the VR4 satellite linked acoustic receivers which make up the Shark Monitoring Network.
The Shark Monitoring Network provides ocean users and land managers with near real-time alerts of tagged white sharks and large tiger sharks. The information is also posted to the shark activity map, SharkSmart WA app and Surf Life Saving WA Twitter feed.
Pop-up archival transmitting (PAT) tags were also being used to collect broad scale movement data.
Where was the catch information from the drumline trial publicly available?
All catch information, including sharks caught and released were made publicly available on the shark activity map, SharkSmart WA app and Surf Life Saving WA Twitter feed.
A summary of all catch data from the two-year trial can be found here
What made the SMART drumline trial different to the 2014 drumline trial?
Between January and April 2014, the former government trialled the use of traditional drumlines, which consisted of a baited hook suspended from buoys, anchored to the ocean floor.
The scientific non-lethal SMART drumline trial was designed as a catch, tag, relocate and release program of target species.
Did the SMART drumline project have environmental and animal welfare approvals?
The trial was referred to the Environmental Protection Authority and it was determined that the trial did not require formal assessment. This was primarily due to the localised impact of the trial, protocols in place and close monitoring. The trial was also approved by DPIRD’s independent Animal Ethics Committee.
Environmental groups such as Sea Shepherd and the Conservation Council of WA were actively engaged in the project through provision of observers and were represented on the Ministerial Reference Group. The Group has supported the operating protocols, which included guidelines on handling animals, if required
What measures were in place to protect by-catch species?
SMART drumline project managers and DPIRD technical staff worked with animal welfare groups and associated Government agencies, such as DBCA, to minimise risks to any by-catch.
Measures included specially designed fishing gear to reduce the likelihood of whale entanglement, hook type, regular monitoring of the SMART drumlines and an immediate response to alerts with contractor to be at the drumline within 30-minutes.
During the two-year trial, 266 non-target shark species were caught including 168 tiger sharks. In addition, 37 smooth stingrays, four pink snapper and two samsonfish were caught on the SMART drumlines.
Excluding the four pink snapper, all animals caught were released alive.
Importantly, during the trial, the average response time to a SMART drumline alert was 11.1 minutes, and the average duration for which animals were on the hook was 27.7 minutes.
How was the SMART drumline project monitored to ensure sharks were treated humanely?
The SMART drumline contractor was identified through a rigorous evaluation process to ensure they had the skills, experience, vessel and capacity to carry out the trial.
As this was a scientific trial, the contractor had and continued to undertake detailed training to ensure they remained familiar with the required science-based tagging and reporting processes. DPIRD technical observers were on board the contractor’s vessel for approximately 35% of fishing days during the two-year trial.
Independent observers, nominated through the Ministerial Reference Group, also had opportunities to observe capture, tagging and relocation operations. Feedback from the reference group was supportive of the contractor’s methods and compliance to animal welfare guidelines and the DPIRD Animal Ethics Committee approved the methods used and was updated on animal welfare outcomes throughout the trial. During the trial, all sharks were released alive. Nine sharks caught as part of the trial were recaptured some time later, providing evidence of the longer-term survival of animals released in good condition.
Why have some NSW SMART drumline trials caught more white sharks?
The numbers of white sharks caught in the NSW SMART drumline trials vary considerably between locations and the duration of the individual trials.
The numbers and sizes of white sharks caught in this SMART drumline trial is a reflection of the different operating environments of each study, the different populations of white sharks off WA and NSW, and the fact that several of the NSW trials occurred in known white shark nursery areas.