Underwater bait setter to save the albatross

There are 22 albatross species in the world, 17 of which are threatened with extinction. Scientists have linked the global albatross population loss to accidental bycatch of seabirds during the commercial longline fishing process.

Every year, approximately 3 billion hooks are set by the global longline fishing fleet. While setting the lines, albatross and other diving seabirds such as petrels can become hooked or entangled and drown as the longline sinks. As a result of this practice, up to 300,000 seabirds are killed annually.

Currently, longline fishermen set branch lines by baiting the hooks and hand casting them into the water, where they are an attractive, easy meal for seabirds. This is not profitable for fishermen as a high number of hooks lose their bait before reaching their target depth, and it is a deadly situation for the seabirds. And while a number of mitigation methods have been employed, no single one has been solely effective in preventing seabird bycatch and all of them make fishing more difficult.

The key to an effective solution was some type of device capable of releasing baited hooks underwater, out of the sight and diving range of the birds. If possible, it should not interfere with fishing or require the use of any additional seabird deterrent measures.

Queensland-based company Amerro Engineering began development of a mitigation device for the pelagic longline fishing industry back in 2006. Control Logic has been proudly involved with the project from day one, providing product and technical assistance with the system interface and control.

Known as the BS30 Underwater Bait Setter, Amerro’s stern-mounted, hydraulically operated device deploys baits on a longline at predetermined depths, effectively setting baits out of the visual sight and diving range of seabirds. To operate the underwater setter, fishermen place a baited hook in a capsule held in a docking station. At the press of a button, a series of hydraulic winches propel the capsule and the docking station down the track.

Once the docking station reaches the bottom of the track it releases the capsule, where it freefalls to a preprogrammed 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 speed of this cycle depends on the preprogrammed depth and can be varied from 8–16 s/4–10 m.

At the heart of the bait setter is a Panasonic PLC, providing high-speed motion control and management of the set depth verses tow speed for the descent and recovery of the capsule. Logging features and operator interface are provided by a Red Lion HMI allowing for logging of the number, location and time of hooks set on a fishing trip. In port, this data can be downloaded to computer via USB providing a way for the skipper to automatically record and track fishing effort for future reference or meeting compliance when reporting to various fisheries managers.

At the time of writing the bait setter system had completed extensive sea trials and set thousands of hooks without a single seabird bycatch. It has significantly reduced bycatch within the pelagic longline industry worldwide and has increased catch potential as a result of eliminating seabird interaction and bait loss.

A commercialised version of the product is now in the marketplace and gaining widespread support from the longline fishing industry. From a commercial standpoint, early indications show that the benefits of getting all baits under the water where they can be effective will return dividends to the fisherman as reward for better ecological practices.