Shark data reveals secrets of the ocean’s apex predators
Five years of data from the shark management strategy has been compiled in an effort to determine the best way forward.
The NSW Department of Primary Industries has released key fact sheets on the SharkSmart website, outlining the different methods used over the years as part of the $16 million project.
The analysis also looks at the pros and cons for each item.
We took an in-depth look at the data for the North Coast.
Drones (October 2018 to April 2019)
● Cudgen Beach, Kingscliff: 12 sharks sighted, 0 beach evacuations
● Main Beach, Byron Bay: 49 sharks sighted, 4 beach evacuations
● The Pass, Byron Bay: 46 sharks sighted, 0 beach evacuations
● Suffolk Park: 8 sharks sighted, 0 beach evacuations
● Lennox Head: 19 sharks sighted, 3 beach evacuations
● Sharpes Beach, Ballina: 41 sharks sighted, 7 beach evacuations
● Shelly Beach, Ballina: 25 sharks sighted, 10 beach evacuations
● Lighthouse Beach, Ballina: 35 sharks sighted, 3 beach evacuations
● Evans Head: 58 sharks sighted, 7 beach evacuations.
PROS: No impacts to sharks or other marine animals, comparatively cheap and easy to operate, in the future automated software and flight paths will be able to detect sharks, targeted flights over a single beach and for events, rapid response and general beach surveillance, help beach authorities to monitor the shark, versatility of drones as a multipurpose surveillance and rescue tool, potential to drop life saving devices to water
users in distress, relatively inexpensive, partnerships between SLS NSW, councils and swimming/surfing groups could reduce costs.
CONS: Currently flights are restricted within 1km of the pilot, proximity to airports may limit use and level of pilot training required, flights not possible in poor weather, eg. strong winds, water turbidity, requires training of operators.
SMART drumlines (December 2016 to September 2019)
● Seven Mile Beach to South Ballina Beach: 20 drumlines deployed daily, 1027 days contracted, 695 days (68 per cent) set, 136 white sharks (one dead), nine bull sharks, 27 tiger sharks, 76 non-target animals (one dead).
● Airforce Beach to Joggly Point: 15 drumlines deployed daily, 1027 days contracted, 776 days (76 per cent) set, 166 white sharks, two bull sharks, 15 tiger sharks, 41 non-target animals (one dead).
PROS: Removes immediate risk to water users and sharks move offshore for a period of time, less harm to sharks and other marine life compared to nets, designed to avoid entanglement with whales, can be set across multiple beaches and large distances, sharks are tagged and movements monitored.
CONS: Comparatively more expensive and labour intensive, requires boat access less than 13km away from the furthest SMART drumline, relies on fair weather, difficulty in accessing ocean eg. river mouths, can restrict fishing days.
Shark listening stations, December 2016 to October 2019
● Kingscliff Beach, Kingscliff: 225 detections
● Clarkes Beach, Byron Bay: 1165 detections
● Lennox Point, Lennox Head: 1006 detections
● Sharpes Beach, Ballina: 1948 detections
● Lighthouse Beach, Ballina: 1174 detections
● Main Beach, Evans Head: 1382 detections
PROS: Improve knowledge of the movement and distribution of sharks, instant alerts, real-time updates, tracking tagged sharks provides DPI scientists with knowledge, public can use app to receive notifications
CONS: Only detects tagged sharks, requires a tagging program to tag sharks to detect.
Helicopters (July 2018 to June 2019)
● Ballina to Point Danger, Tweed Heads (104km each way): 144 days contracted, 38 days flown (26 per cent), eight white sharks, 195 bull sharks (large schools over two days), eight tiger sharks sighted, 28 beach evacuations.
PROS: No impacts to sharks or other marine animals, provides surveillance at unpatrolled beaches, able to cover large areas of the coast, help guide beach authorities to the shark to
herd it out to sea.
CONS: Relatively expensive, surveillance is limited at any one beach to only a short time while flying overhead, relies on good conditions (e.g. water turbidity/sea surface chop) to allow sharks to be spotted, requires training of observers.
● Trial 1: Eco Shark Barrier at Lighthouse Beach, Ballina. Installation was attempted over three months, but only the concrete blocks to mark the northeastern corner of the barrier in front of Ballina Head were installed. East coast lows, highly mobile sandbanks, and constant exposure to ocean swells at Lighthouse Beach prevented installation. The trial was discontinued.
● Trial 2: Global Marine Enclosures - Aquarius Barrier at Seven Mile Beach, Lennox Head. All anchors, weights and ground chains were installed and two of the three barrier walls. The eastern wall was irreparably damaged by sea conditions. The trial was discontinued.
PROS: Swimmers use the ocean without the fear or risk of shark interactions, minimal impact to marine life.
CONS: Appropriate engineering and environmental assessments along with community
consultation must be undertaken prior to barrier installation, there are currently no commercially available barriers that protect surfers, barrier products are only suitable for NSW estuaries or highly sheltered coastlines, requires regular cleaning and maintenance to remove seaweed and biofouling.
● Trials were held at Lennox Head, Sharpes, Shelly, Lighthouse, Evans Head from December 2016 to May 2017 and November 2017 to May 2018
● Caught in nets: 3 white (2 dead), 5 bull (3 dead), 3 tiger sharks (1 dead), 64 other sharks (59 dead), 301 rays (107 dead), 8 marine mammals (8 dolphins dead), 20 turtles (9 dead), 16 fish (16 dead).
PROS: Relatively low in cost compared to other methods, they can stay in the water all day and night.
CONS: Nets are not a barrier and are only 150m long so sharks can swim over, under and around nets, are only set in swimming season to avoid whale entanglement, catches around 90 per cent of non-target animals, especially rays and harmless sharks.
● Chillax Wax: Wax applied to the top of surfboard. Reduced white shark interactions by 14 per cent
● Ocean Guardian Freedom+ Surf: Electrode stickers placed on bottom of surfboard, electronics incorporated within tail kick of back grip (electrical). Best performing of tested products. Reduced white shark interactions by 56 per cent
● Rpela: Electrode and electronics built-in on bottom of surfboard (electrical). Reduced white shark interactions by 12 per cent
● SharkBanz surf leash: Incorporated within surfboard leash (magnetic). Reduced white shark interactions by 10 per cent
● SharkBanz bracelet: Worn on ankle or wrist (magnetic). Reduced white shark interactions by 6 per cent.
PROS: Aims to reduce the chance of a shark interaction to an individual (especially surfers), accessible to individuals surfing/swimming in remote locations or want extra protection, don't harm sharks or other marine life, environmentally safe, convenient/easy/wearable.
CONS: Invest in a device independently tested and verified, cost to individual beach goers, already used by some tourism operators for their business, multiple devices required if a surfer has more than one board.