The Department of Environment (DoE) has completed 62 of the 200 deep drops it needs to decide whether to buy an Australian-made electric shark deterrent for Cayman anglers, it said on 15 September 2026. The department wants the remaining 138 finished by the end of September or the beginning of October.

Deep dropping is fishing with baited lines sent to the sea bed in deep water, in Cayman's case for snapper. The department's 15 September statement says that "In July DoE began trials with the Rpelx device with local anglers who fish for deep water snapper", and that "The trial aims to collect data on 200 deep drops, 100 with the Rpelx and 100 without the device." The anglers fish while DoE staff record the data.

What the trial is meant to settle is whether a device the manufacturer sells at AU$299 stops sharks taking hooked fish and tackle without also cutting the catch. The DoE says the same encounters injure sharks that are protected by Cayman law, and it describes the trial as part of a three-year shark study funded by the UK Government.

That study, "Safeguarding vulnerable life-stages of shark populations in the Cayman Islands", carries the Darwin Plus reference DPLUS225 and a £619,181 grant, with Oregon State University in the U.S. as project partner, according to the Darwin Plus project record, which lists it as running from 1 January 2026 to 31 December 2028. The DoE said in its statement of 11 March 2026 that its Shark Research and Conservation Programme is also supported by Cayman Islands Brewery, through the White Tip Lager Conservation Programme. The department first raised the idea publicly on 27 August 2025, in a statement that asked fishermen and charter companies to complete a survey to establish "whether there is community support for this campaign and if so, the number of devices needed for the trial".

The 15 September statement sets a condition for going further. "If the device proves successful in deterring sharks without major impacts on the fishing experience, the project will move on to phase two of the trial where the DoE will purchase and provide the Rpelx device to local anglers to keep and report back on the long-term effects," it says. Dr Johanna Kohler, Manager of the Shark Research and Conservation Programme at the DoE, said in the 15 September statement: "We need robust evidence that the Rpelx device works for anglers in Cayman to justify the expense of purchasing more devices." In the same 15 September statement she said: "The more help we can get with testing the device now, the quicker we can move on to phase two so fishermen can have their own device full-time."

Sixty-two of 200 drops is 31% of the target, although the 15 September statement itself puts the 62 drops at "just over ¼ of the target number", and the department's own schedule leaves between two and three weeks for the other 138. The DoE is asking anyone who fishes for deep-water snapper to take part in the remaining drops.

What is being measured

On each trip the researchers log, in the words of the 15 September statement, "environmental conditions, boat length, engine type, location, depth, time taken until first bite, fight time, reel type (standard vs electric), and how many fish, hooks, sinkers are lost to sharks, and how many fish are landed intact." Anne Veeder, Research Officer with the DoE Shark Research and Conservation Programme, said in the 15 September statement: "This way, by the end of the trial the DoE can provide meaningful results to the fishing community such as whether the device affects the catch rate, number, size or species of fish, and whether it is successfully managing to deter sharks."

The device and what is known about it

The Rpelx is made in Western Australia by a company of the same name, which sells it direct at AU$299 and states on its product page that the unit carries a "3m electromagnetic protection field" and is "Rated to 100m deep", as of 16 September 2026. The 200-volt output is also recorded in the peer-reviewed trial of the device, which states that "The device has an output of 200 V and creates an electromagnetic field between the battery module and bottom electrode"; the depth rating is the manufacturer's claim and was not tested in that study.

Sharks, rays and skates detect very weak electric fields through sensory organs known as ampullae of Lorenzini, according to a 2019 review of electroreception in marine fishes by Newton, Gill and Kajiura in the Journal of Fish Biology. The marine bony fish that deep-drop anglers target carry no equivalent organ, and the Australian field trial described below states that the fields these devices generate "would not affect target fish species, which do not possess an electrosensory system". Dr Kohler put the effect on a shark more plainly in the 15 September statement: "To the shark it feels like a strong punch in the face, and it will turn away." Announcing the grant on 11 March 2026 she said: "Target fish do not have electro receptors so the device will only deter sharks and not fish in general." Whether that holds for Cayman's snapper is one of the questions the 200-drop comparison is set up to answer.

The only published field test

The one peer-reviewed field trial of the device was led by Dr Jonathan Mitchell, an adjunct research fellow at the University of Western Australia, and published online on 26 February 2026 in the CSIRO journal Marine and Freshwater Research (Mitchell et al., vol. 77, article MF25165, doi 10.1071/MF25165). Across 11 days of deepwater line fishing at the Cocos (Keeling) Islands in the Indian Ocean, covering 51 fishing sessions and 262 fish, the paper reports the device "reducing the probability of a depredation event occurring by 63%", meaning the chance of a shark taking a hooked fish, and adds that it "also reduced shark bycatch and loss of fishing gear". The authors state that further testing "in other demersal line fisheries", meaning fisheries for bottom-dwelling species, "is strongly recommended", which is what the Cayman trial is.

Two qualifications sit in the paper itself. The device's owner was one of its nine authors: the conflict-of-interest declaration states that "D. Smith is the founder and owner of RPELX. The authors declare that they have no further conflicts of interest." The study was funded by Parks Australia under the Indian Ocean Territories Marine Parks grant scheme, and the paper records that the funder "had no involvement in the collection or analysis of data nor the writing of the publication". The paper also reports that the skipper, as well as the treatment, had a significant effect on the number of fish taken by sharks.

The anglers

Two anglers quoted in the 15 September statement describe the problem from the boat. "We immediately got sharked on the first drop," Captain Stephen Ebanks, who runs the local fishing charter Reel Vibes, said in the 15 September statement. "This happens all the time, in some areas more than in others but it is a problem and I am glad the DoE is working on a solution." King Flowers, described in the same 15 September statement as "owner of the Brasserie", said: "If it happens one time, that is fine. But on some days, we only get a quarter of the usual catch and the time for repairs of the fishing tackle add up quickly."

The sharks and the law

The DoE says the losses run in both directions. "We have had reports from divers with the citizen science Sharklogger Network, of individual sharks swimming around with hooks, deep wounds, injured fins, and even a gaff stuck in the jaw," Ms Veeder said in the 15 September statement. The department says most of these encounters involve large sharks from the breeding population, potentially including pregnant females.

Sharks and rays are listed in Schedule 1 of the National Conservation Act, 2013 (Act 24 of 2013) as species "protected at all times", and section 33 makes it an offence to take, possess or offer for sale a specimen of a protected species; the Act defines "take" as "to collect, hunt, kill, destroy, damage, injure, disturb, harass, harm, wound, capture, molest or impede a live specimen in any way or to attempt to do so, and includes incidental taking". The Act was brought into force in stages by three commencement orders: its commencement note records that Parts 4 and 6 and Schedule 1, which between them carry the protection and the offences, came into force on 22 April 2015, consistent with the DoE's shark protection page, which says the Act has been "in force since 2015".

Neither the 15 September statement nor the published grant documents state what the trial has cost or what a phase-two purchase would cost. On the department's own timetable the 138 outstanding drops fall due between the end of September and the beginning of October 2026, and the phase-two purchase turns on what they show. Beyond the deterrent, Dr Kohler said when the grant was announced on 11 March 2026: "At the final stage of the project, we will look at the data and engage with the community and relevant organisations to discuss possible mitigation responses."