Longline device wins 2011 Smart Gear Competition

Mr Yamazaki, a captain on a Japanese tuna vessel, received a $30,000 grand prize, and also received the special tuna prize of $7,500, offered by the International Seafood Sustainability Foundation (ISSF).

The device is designed to reduce seabird bycatch in pelagic longline fisheries when used in combination with tori lines and in some cases night setting. The double-weight configuration is designed to sink pelagic longline hooks beyond the range of seabird attacks within the aerial extent of a tori line during line setting, and to reduce injuries to crew should a hook come free while under tension in the landing process and recoil back at the vessel.

The Yamazaki double-weight configuration consists of two leads placed at either end of a 1 to 1.5m section of wire or wire trace. This weighted section is inserted into a branchline 2m above the hook. The weight nearest the hook is free to slide along the branchline while the second lead is fixed. The double weight reduces the danger of weight recoil injury by:

• Spreading the mass of the weights (two smaller weights are better than one) across the wire trace
• Including a sliding weight that dampens the speed at which the weight can recoil; including a 1 to 1.5m section of stretch resistant line (wire) which serves to also reduce recoil energy; and positioning the larger of the two weights in or near the hands of a crewman as the fish is under maximum tension as it approaches the sea door

The device has proven to be safe and effective at reducing seabird bycatch in pelagic (tuna) longline fisheries. In 2010, over 95,000 branch lines with the Yamazaki double-weight system were hauled with no injuries to fishermen, reducing seabird bycatch by 89% more than un-weighted branchlines, with no effect on fish catch rates.

The conservation potential of this device is substantial. Some countries have opposed branchline weighting for seabird conservation due to serious safety issues. The Yamazaki double-weight branchline is an innovation that meshes practicality and safety with function and conservation and breaks down the barriers to the adoption of branchline weighting as a seabird bycatch mitigation measures in world tuna commissions and in domestic fisheries. Mechanistically weighting branchlines forces baited hooks to sink quickly to depths beyond the reach of seabirds within a distance that can be protected with bird-scaring lines.

WWF says that branchline weighting and bird scaring lines deployed properly are the one-two punch answer to seabird conservation in tuna longline fisheries. Used in combination with night setting, seabird bycatch should can be reduced to the lowest level possible. This innovation also paved the way for the Agreement for the Conservation of Albatrosses and Petrels to endorse the simultaneous use of branchline weighting, bird-scaring lines and night fishing as best-practice seabird bycatch mitigation in pelagic longline fisheries.

It has the potential to spread this conservation success to the oceans of the world and allow tuna fisheries and albatrosses and petrels to coexist.

Runners-up
Two prizes of $10,000 were awarded to the two runners-up - The SeaQualizer and Turtle Lights for Gillnets.

The SeaQualizer (Bill Brown, Jeffery Liederman, Patrick Brown and Ryan Brown, USA) is a non-invasive, pressure activated, fish recompression tool that is capable of releasing fish at targeted depths and represents a breakthrough in bycatch release technology that could have a major impact on the management of recreational fishery mortality.

A significant problem in the management of some recreational fisheries is the mortality of bottom dwelling fish (fish with air bladders) that are released at the surface. When brought to the surface from depth these fish undergo barotrauma due to the air bladder expanding with reduction in pressure.

The SeaQualizer appears to be very effective and capable of increasing the survival rate of fish that are experiencing barotrauma symptoms by releasing them after they have been returned to depth and sufficiently recompressed. It reduces the time and effort an angler must expend to repeatedly reel heavy weights all the way up from the bottom and the SeaQualizer can also accommodate the release of many species of fish, both large and small.

The Turtle Lights for Gillnets (Shara Fisler and John Wang, USA) and their ability to reduce the bycatch of turtles has the potential to be an effective device for turtle conservation all over the world. The idea uses widely available fishing lights (LED or chemical lightsticks) to illuminate gillnets and trials have reduced green turtle interactions by 60% without affecting target catch rates or catch value.

The experimental work for this project was undertaken in Baja in an area with high concentrations of green turtles. The team hypothesizes that illuminating nets creates enough of a visual cue to alert sea turtles to the presence of a barrier, allowing them to avoid it. Anecdotal evidence suggests that sea turtles swim up to an illuminated net and move along side it until they turn away.