Sub-surface bait setting

Methods that reduce bycatch by eliminating gear sets at the ocean surface by changing the property of fishing lines so that they are less likely to catch or ensnare animals feeding at the surface or in the mid-water column. These include devices such as setting chutes that place sets below the ocean surface in longline operations where they are less prone to seabird predation, and setting gillnets below the sea surface to reduce entanglement rates of small cetaceans (Hembree and Harwood 1987). They can also be used on longline vessels to increase the speed at which baited lines get below the water’s surface where seabird predation mainly occurs (Robertson et al. 2010). Other examples include low profile line, a kind of rope linking lobster pots that might be suspended deep enough to avoid whale entanglements but with enough floatation to lie above rocky bottoms that tend to abrade them. Weighted mainlines may also increase the sinking ate of pelagic longline gear, making it less likely to capture surface-feeding seabirds (Moreno et al. 2008). Frozen bait can be thawed before it is set in the water to increase the rate at which it sinks in longline fisheries. (The sinking rate can also be increased by puncturing the swim bladder of fish bait) (Gilman et al. 2007).

Displaying 11 - 15 of 15

Study Type: 

Field study in the wild

Location: 

Eastern Australia

Target catch: 

Tuna

Effect on bycatch species: 

Live bait sank more quickly than dead bait, increasing the exposure of hooks to seabirds but the sink rates of individual live bait species were very variable. With respect to dead bait, those on the 160 g leaded swivel with a distance of 2 m leader len

Effect on target catch: 

None reported

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Study Type: 

Field study in the wild

Location: 

Eastern Australia

Target catch: 

Tuna

Effect on bycatch species: 

Mainlines with a loose configuration reached depth more slowly than tight configurations, allowing more time for seabirds to become incidentally hooked

Effect on target catch: 

None reported

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Study Type: 

Field study in the wild

Location: 

South Africa

Target catch: 

tuna

Effect on bycatch species: 

Catch rates of birds were higher on unweighted compared to weighted branchlines.

Effect on target catch: 

Catch rates of fish were not significantly different between the two branchline types at night or during the dawn.

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Study Type: 

Field study in the wild

Location: 

Norway

Target catch: 

Torsk (Brosme brosme), ling (Molva molva) and haddock (Melanogrammus aeglefinus)

Effect on bycatch species: 

Reduced incidental capture of seabirds, mostly fulmars

Effect on target catch: 

Increased target catch rates

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Pages