Line weighting is a widely used and effective way to get baited hooks out of the diving range of seabirds more rapidly.
The problem
Fishing operations and seabird foraging zones overlap. Seabirds are attracted to fishing boats as they recognise them as a source of food.
Seabirds can get caught during both setting and hauling.
- During line setting – seabirds may attack baits on the surface or underwater to about 10 metres and become hooked or ensnared in the fishing gear and drown.
- During line hauling – seabirds may attack leftover baits as the catch is brought on board. Birds may become hooked or entangled, and injured or killed.
The solution
As pelagic longlines are set close to the surface, branch lines are weighted individually rather than weighting the mainline.
When pelagic longline operators are fishing south of 25° South latitude, branch lines are weighted with sliding luminescent leads or weighted swivels.
This enables the branch lines to sink further down in the water column more quickly than the mainline, reducing the likelihood of incidental seabird capture.
More information on line weighting – demersal can be found at afma.gov.au.