A team of Australian inventors has won the WWF Smart Gear award, aimed at innovative ideas for fishing "smarter".
The Underwater Baited Hook device allows longline vessels to set baited hooks underwater, out of reach of seabirds. Designed for use on coastal tuna and swordfish vessels worldwide, the invention minimises or eliminates accidental mortality of seabirds including albatrosses, petrels and shearwaters, which are sometimes killed in the fishing gear when they attempt to seize the bait attached to the longline hooks.
The $30,000 prize was accepted by Phil Ashworth, general manager of Australia-based Amerro Engineering at the World Fishing Exhibition in Vigo, Spain. Mr Ashworth worked alongside Graham Robertson, a principal research scientist with the Australian Antarctic Division, on this project.
The stern-mounted, hydraulically driven device delivers baited hooks underwater, below vessel propeller turbulence, in a method different to setting baits on the water's surface, which could substantially reduce bycatch. And because it minimises the drag caused by devices that remain underwater while setting, it is considered the most fuel-efficient method of delivering baited hooks at required underwater depths.
To operate the device, fishermen place a baited hook in a capsule chamber, then mount the capsule in a docking station that is fixed to the vessel. There it is secured to a carriageway by spectra rope attached to pulleys and operated by hydraulics. With the press of a button, the hydraulics propel the capsule down the carriageway, out of which the capsule freefalls to a pre-programmed depth. At the end of the descent, the system reverses the hydraulics, flushing the baited hook from the capsule through a spring-loaded door. The capsule then returns to the docking station to be set again. The aim is to release baited hooks beneath the lower limit of propeller turbulence, so that the turbulence forms a curtain of opaque water above the sinking bait, shielding it from the eye of scavenging seabirds.
In March 2009 researchers set 300 underwater baited hooks and ran extremely successful trials. Results showed that bait quality and bait retention on hooks were not affected by the new method of deployment, so that use of the device is unlikely to affect the catch rates of target and non-target fish species.
