Longline Guidebook
When weight is added to a branchline, the baited hook sinks faster and reduces the time that seabirds can access it. This is commonly done using weighted swivels on the branchline.
Best Practice line weighting recommended by ACAP is to have at least 40 g (1.41 oz.) within 0.5 m (1.64 feet) from the hook, at least 60 g (2.11 oz.) within 1 m (3.28 feet) of the hook, or at least 80 g (2.82 oz.) within 2 m (6.56 feet) of the hook. RFMOs have not adopted the most recent scientifically backed evidence on line weighting yet, and have a lesser requirement of at least 45 g (1.58 oz.) within 1 m (3.28 feet) of hook, at least 60 g (2.11 oz.) at less than 3.5 m (11.48 feet) from hook, and at least 98 g (3.45 oz.) at less than 4 m (13.12 feet) from the hook. In the SW Pacific, there is also the option of making one weight greater than or equal to 40 g (1.41 oz.) within 50 cm (1.64 feet) of the hook.
Some fishers have expressed a reluctance to use leaded swivels due to safety concerns, as weighted swivels could cause serious injury if they recoil back at the crew in the event of a line breakage. By employing “safe leads,” which are designed to slide off the branchline in the event of a breakage, this risk can be minimized.
