Excluder devices

These can consist of a grid of metal bars or mesh placed usually within the neck of a trawl that has an opening for escape at either the top or bottom. Examples include “skylights” which consist of a mesh opening located at the top of the codend. ”Skylights” can be combined with guiding funnels that create visual and tactile stimuli to direct finfish towards the “skylight” escape sections. A different but similar type of design is the fisheye (including Gulf and yarrow fisheyes and bigeyes) which are openings typically forming a rigid frame constructed of aluminum or steel rods and placed along the top center portion of the codend (i.e. Catchpole and Revill 2007). Typically, large animals that strike the bar exit through the opening, while the smaller target species pass through the bars and are captured in the net or codend. Examples of excluder devices in trawls are the Nordmore grid, the Turtle Excluder Device (TED), and the Sea Lion Excluder Device (SLED). A sea turtle excluder chain mat is used in the Northwest Atlantic scallop dredge fishery. A new modification to pound nets may reduce sea turtle bycatch by replacing the upper two-thirds of the leader netting with vertical ropes spaced wide enough apart to let sea turtles swim through without becoming entangled (DeAlteris et al., 2005).

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Study Type: 

Field study in the wild

Location: 

Northern Australia

Target catch: 

Prawns

Effect on bycatch species: 

Reduced the number of sharks and rays by 35% when the Popeye Fishbox was placed 70 meshes from the codend draw strings and by 27% when it was placed 100 meshes from the codend draw strings

Effect on target catch: 

Did not significantly reduce the catch of prawns

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Study Type: 

Field study in the wild

Location: 

Western Australia

Target catch: 

Red emperor, scarlet perch, spangled emperor, Rankin cod, blue spot emperor, rosy threadfin brea, flagfish, frypan snapper, red snapper and goldband snapper

Effect on bycatch species: 

No rays larger than 120 cm were caught when the grid was used

Effect on target catch: 

None reported

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Study Type: 

Field study in the wild

Location: 

Florida

Target catch: 

Shrimp

Effect on bycatch species: 

Florida fisheye bycatch reduction device (BRD) did not significantly reduce finfish bycatch. The large-mesh extended-mesh funnel BRD significantly reduced bycatch. The simulator cone (used with both BRD's) significantly reduced bycatch.

Effect on target catch: 

Florida fisheye BRD retained shrimp. The large-mesh extended-mesh funnel BRD had low shrimp loss at Tarpon Springs but at Biscayne Bay shrimp loss was significant. The simulator cone (used with both BRD's) resulted in significant shrimp loss.

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Study Type: 

Field study in the wild

Location: 

Northern Australia

Target catch: 

Prawns

Effect on bycatch species: 

JT 2 design reduced finfish bycatch by 5%

Effect on target catch: 

Caught 5.2% more tiger prawns and 6.9% more endeavour prawns than standard net

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Study Type: 

Field study in the wild

Location: 

Northern Australia

Target catch: 

Prawns

Effect on bycatch species: 

JT 2 design did not prevent capture of large sharks and rays

Effect on target catch: 

Caught 5.2% more tiger prawns and 6.9% more endeavour prawns than standard net

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Study Type: 

Field study in the wild

Location: 

Northern Australia

Target catch: 

Prawns

Effect on bycatch species: 

JT 1 design did not prevent capture of large sharks and rays

Effect on target catch: 

Caught 6.6% more tiger prawns and 10.5% more endeavour prawns than standard net

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Study Type: 

Field study in the wild

Location: 

Northern Australia

Target catch: 

Prawns

Effect on bycatch species: 

JT 2 design did not prevent capture of sea turtles

Effect on target catch: 

Caught 5.2% more tiger prawns and 6.9% more endeavour prawns than standard net

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Study Type: 

Field study in the wild

Location: 

Northern Australia

Target catch: 

Prawns

Effect on bycatch species: 

JT 1 design did not prevent capture of sea turtles

Effect on target catch: 

Caught 6.6% more tiger prawns and 10.5% more endeavour prawns than standard net

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

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