Image: Dave Goad | Creative Commons
Tori line on fishing boat.
Bird-scaring lines (tori)
Find out about the seabird-safe practice of bird-scaring lines.

A bird-scaring line (BSL), also called a 'tori-line', is a line towed from a high point at the stern of the vessel. As the vessel moves forward the section of the line closest to the vessel is lifted off the water. This lifted section has flapping streamers that scare seabirds away from sinking baited hooks.

The BSL is attached to a strong, purpose built pole (tori pole). If two BSL are used, with one on each side of the fishing line, this makes it even harder for seabirds to grab baited hooks.

Effectiveness

A BSL can reduce reduce seabird captures by 40% to 80% and scientific proof of this level of effectiveness is high. Effectiveness depends on the types of seabirds in the area, and whether the BSL is designed and used correctly.

Limitations

Once baited hooks float past the section of the BSL in the air, they are not protected. Diving seabirds can dive down and bring them to the surface. Seabirds that are not good at diving like albatrosses can grab the baited hook off the diving seabird and become caught. Adding night setting and line weighting further reduces the risk of seabirds becoming hooked.

Effect on fish catch

None.

Minimum standards to be effective

tori-pole-credit-ed-melvin-390.jpg
Tori pole
Image: Ed Melvin 

Tori pole

A BSL is attached to the vessel by a pole with an angle, called a tori pole. When setting a longline, fishers throw the baited hooks so they land to the side of the vessel, away from the water that is stirred up by the vessel and the propeller.

The tori pole angle holds the BSL so it hangs to the side, over the baited hooks. The tori pole makes sure the BSL is at least 8 metres above the water.

BSL line

The line is 200 metres long and has two sections – one section is in the air and the other is in the water.

For the section in the air, a braided (plaited) line prevents the line twisting. A short section of lower strength line (called a ‘weak link’) can be added to the line so that if the BSL tangles with the fishing gear the BSL breaks and doesn’t affect the setting process. If this happens, the spare BSL can be used.

A recovery line (sometimes called a ‘lazyline’) is attached from the line to the tori pole to make it easier to bring the BSL back on board after line setting finishes.

For the section of line in the water, non-twisting braided rope such as 9mm polyester or nylon is used. This type of rope stops the line spinning and tangling the streamers.

BSL streamers

These are a mix of long streamers and short streamers.

Long streamers are flexible, ultra-violet (UV) protected, bright orange tubing such as kraton (see sourcing materials below). Streamers can be attached to the line with a double eye swivel so they don’t tangle with the line. The streamers are spaced at 5 metres apart and reach the water.

Another way to add drag is to make the water section of the line even longer.

Sourcing materials

Streamer material: Beaulin sell Beautori streamer tubing. They also sell Kraton.

Cost

  • A BSL can be made for around US$300
  • A tori pole can be purchased for around US$600

Solving problems

Problem: Tangles with the fishing gear

Solutions: 

    • Use a tori pole with a swinging arm that holds the BSL over the baited hooks, away from the fishing line.
    • Make sure there are no tangle points in the in-water drag section, to allow surface floats to slip over the backbone.

Problem: If the BSL tangles with the fishing gear, the tori pole could break

Solution: Use a weak link in the line, or a tension release.

Problem: The BSL is difficult to bring back on board at the end of setting

Solution: Add a recovery line between the BSL and the vessel to help lower the BSL so it can be reached. Use a reel to wind in the BSL.

Problem: Streamers roll up around the BSL line

Solutions: 

    • Add a swivel in the BSL line at the vessel end so it can spin
    • Use a double eye swivel in the BSL line and attach the streamers to one eye
    • Braided line, also called plaited line (multiple small fibres woven together in opposing directions) will not spin when it is towed through the water and should be used in place of stranded line

Case study

A Fijian women's group has made 62 bird-scaring lines for high seas vessels visiting Suva. These are given to vessel captains by BirdLife International’s Port Based Officer.

Read more about this story

More information

Mitigation practical information on seabird bycatch mitigation measures: Pelagic longline: streamer lines (vessels ≥ 35 m)