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Australian innovation could be the key to SAVING the WHALES by Ross Tester 18  Silicon Chip Each year around the world enormous numbers of marine mammals are caught in both commercial fishing nets and the shark nets protecting our beaches. Now an Australian company has come up with a way to warn cetaceans – dolphins, porpoises and soon whales – away from nets and hopefully save many of these magnificent creatures from becoming what is euphemistically known as “by-catch”. www.siliconchip.com.au siliconchip.com.au C ommercial fishermen hate seeing whales, dolphins or porpoises entangled in their nets. Fishermen would much rather large mammals stay away from their trawl nets. Unfortunately, the very fish they are catching often attracts such animals – and they end up as part of the catch. Apart from the damage to the nets (and the down-time for necessary repairs and/or the cost of replacement), a significant amount of their catch can actually be eaten by the time the mammal is freed, more likely dead than alive. World-wide, it is claimed that around 300,000 of these creatures are accidentally entangled and drowned in commercial fishing nets. Shark nets As far as against protective shark netting off popular beaches goes, the arguments for and against drag on, with plenty of heat on both sides. While proponents point out the effectiveness of shark nets in saving humans from attack (for example, there hasn’t been a fatal shark attack off a Sydney ocean beach since nets were first introduced in 1937, after many attacks over previous years) opponents consistently point out the numbers of “other” marine animals caught and usually killed by the nets. Again, most of the time, it’s the “emotive” marine mammals including whales, dolphins and porpoises which attract attention from both tabloid media and some of the more alarmist websites. The Pinger But now at least, dolphins and porpoises in particular have a guardian angel in a Sunshine Coast (Qld) company called Fumunda Marine and its cetacean warning device, commonly known as the “Pinger”. The small (46 x 152mm) and light weight (210g) Fumunda Pinger is designed to be attached to a net. It emits a 300ms pulse at 10kHz every four seconds, with a sound pressure level in water of 132dB. This frequency was chosen for two reasons: (a) it is known that dolphins and porpoises can hear it. More importantly, numerous independent scientific studies performed around the world over the past twenty years on different species and populasiliconchip.com.au Director of Fumunda Marine, James Turner, shows his company’s “Pinger” which has been reported to reduce by-catch by 80-95%. While the model he holds is intended for dolphin and porpoise repelling on commercial fishing nets, Fumunda are currently developing a Pinger specifically intended to reduce whale entanglement in commercial fishing nets and beach shark nets. tions of dolphins and porpoises have shown that it has the longest trackrecord of any signal for reducing dolphin and porpoise by-catch. Tests also confirm that Pingers are over 90% effective in reducing dolphin and porpoise by-catch in commercial net fishing practices. The Pinger has undergone extensive testing at the US Navy’s Transducer Evaluation Center (TRANSDEC) Un- derwater Facility in San Diego, California which performs research, development, preproduction and acceptance testing of underwater electro-acoustic transducers for numerous Navy and private party customers. Inside the Pinger While exact circuit details are a closely-guarded secret, Fumunda’s James Turner has revealed that it is February 2010  19 to ping for about two minutes – again confirming its operation. Operation A close-up of the commercial fishing Pinger, showing its tiny size relative to the hand holding it. The two electrodes seen on the body are responsible for turning the unit on when it is lowered into seawater. controlled by a Pic micro, which sets up the various timing circuitry to initiate the short 10kHz discharge via an inductor into a piezo transducer. The result is the characteristic “ping” (not unlike a submarine sonar) which gave the unit its name. While the unit can be heard operating in air (in fact that, in conjunction with oscilloscope waverforms, is how Fumunda’s quality control ensures they are working correctly. Each is compared to a known standard to ensure it is within specification). The whole unit is potted in resin and encased in a very strong, solid elliptical case, designed to slip through the water with minimum drag on nets. A great deal of attention was paid to the design and manufacture of the case – instead of being moulded or cast, the cases are CNC machined from a solid rod of a special co-polymer to tolerances not much more than 1 micron. from the fishing or shark net to have the battery replaced – as long as it is out of the water, it can be achieved in minutes. Because it is audible to humans, no special test gear is necessary to confirm that the Pinger is working before it goes back in the water. And when it is removed from the water, it continues The Pinger only starts operating when it is immersed in seawater. That’s the function of the two electrodes you can see in the above photo. As everyone knows, sound travels significantly better through water than through air – by a factor of six times. That’s why the SPL in water is a rather staggering 132dB and is also another reason why the targeted mammals can hear it so well. Incidentally, fish, sharks and other marine animals do not have the same sense of hearing that mammals do (in fact most have none at all), so are essentially undisturbed by the Pinger – even when operating right next to them. A significant amount of by-catch occurs at night when the nets are all but invisible in the water (during the day, they stand out much more). What the Pinger does is acoustically “illuminate” the net. It doesn’t so much say “Danger, Will Robinson” as say to the animal that there is “something” there to be wary of. Many cetaceans navigate by eco-location. They learn that certain areas are no-go zones which hopefully will keep them safe from the nets with Pingers on them. In some ways, the Pinger operates like a fish finder, except that Battery replacement One end of the case is removable to allow the user to replace the battery (earlier devices had to be returned to the manufacturer or agent to replace the battery). Even so, battery life is estimated at two years, based on 12 hours per day usage. The Pinger also doesn’t have the disadvantage of having to be removed 20  Silicon Chip This Pinger is “laced” into a commercial fishing net. The shape and material of the Pinger case makes it offer minimal resistance in the water, minimising any extra drag on the nets. Each Pinger can operate up to two years before the battery needs to be changed – a task which can be undertaken on the deck of a fishing boat quite quickly and easily. siliconchip.com.au in this case it is not looking for any echo from the fish. Of course, while the Pinger is based on a lot of scientific studies and observation of mammal behavior, it is still based on theory. If anecdotal evidence is any guide, the Pinger has proved to be effective in reducing by-catch. But there is obviously a long way to go and a lot more information to be gathered. In Australia, there are around 1700 commercial fishing licences. Fumunda believe it would take around 12,000 Pingers to cover the Australian fleet. But that is just Australia, where there is no legislation forcing such devices to be used. That’s a pretty significant market. But that pales into insignificance when compared to the overseas market. It is enormous, especially now that much of Europe is widely enforces their use under the European Commission (EC) code 812/2004. In the USA National Marine Fisheries Service (NMFS) regulations enforces the use of Pingers in certain areas of the commercial fishing industry. The Pinger meets both of these codes and is now being sold in both areas. 100 MHz MSO 8M Samples 14 bit High Resolution Spectrum Analysis Whale protection We’ve concentrated on dolphins and porpoises in this feature but arguably the most public outcry occurs when a whale is caught in a net. Various methods have been tried to keep whales away from nets in the past, including playing the sound of a killer whale underwater. But as recently as last October, a juvenile humpback whale was caught in nets off the Gold Coast while this technique was in use. Four humpbacks were caught during 2009. However, whales are known to respond to lower-frequency signals than other cretaceans so recently Fumunda Marine started working with the Queensland Department of Primary Industries and Fisheries to reduce the number of migrating whales caught in shark nets along the east coast of Australia Approximately 12,000 whales travel up and down the east coast each year. The team at Fumunda, like the New South Wales and Queensland Departments of Primary Industries want to reduce the number of incidental entanglements. On the west coast more than 17,000 Humpback whales make the migration to the warmer northern waters for breeding, having to navigate through thousands of lobster pots which are set everyday. Fumunda marine believe whale Pingers could very easily be deployed in clusters of lobster pots to reduce the risk but have yet to convince the West Australian authorities. The latest whale Pingers have been designed to operate at a much lower frequency – about 3kHz – which is known to be audible to whales. As distinct from dolphin/ porpoise Pingers, the whale Pinger operates with a constant frequency tone. As well as being significantly smaller and lighter, making handling and fitting to the nets much easier, the new whale Pingers will also be significantly more powerful than the existing models,. They will be made using high quality internal components and long-lasting replaceable batteries, ensuring reliable performance. The whale Pinger technology has applications globally and the company hopes to work with other stakeholders to further protect these wonderful marine mammals. SC siliconchip.com.au High Resolution Spectrum Analysis Spectrum Graph zoom: Capture a 50Mhz bandwidth with 50 Hz resolution. Zoom on any point. Using the 14 bit ADC, you get a -85 dB noise floor over the whole bandwidth. Use the hardware moving average filter to further improve this. Example: Example Capture 1.000 and 1.001 MHz mixed signals. Display the signals with 50 Mhz bandwidth. Intermod is -80 dB! Check out High Resolution Spectrum Analysis on the Examples page at www.cleverscope.com + Two mixed signal triggers + Protocol decoding + Spectrum analysis + Symbolic maths + Custom units + Copy & paste + Signal generator + USB or Ethernet + 4 or 8M samples storage + 100 MHz sampling + Dual 10, 12 or 14 bit ADC + Ext Trigger, 8 Digital Inputs + 1 MSa/sec charting Distributors: Grantronics - Sydney www.grantronics.com 02 9896 7150 Trio Smartcal www.triosmartcal.com.au 1300 853 407 LE Boughen – Queensland www.boughen.com.au 1800 068 663 www.cleverscope.com February 2010  21