Acoustic harassment devices

Devices that emit sounds of such high intensity that they cause pain or alarm in certain underwater species. The minimum sound level is approximately 200 dB re 1 _Pa @ 1m. References for AHDs primarily dealt with aquaculture operations. These devices may exclude some animals from important habitat (Olesiuk et al., 2002), and pose a risk of impairing an animal’s hearing. These drawbacks render this approach potentially harmful and dangerous.

North Atlantic right whales (Eubalaena glacialis) ignore ships but respond to alerting stimuli

Study Type: 

wild

Location: 

Bay of Fundy

Target catch: 

na

Effect on bycatch species: 

Whales showed a strong response to alert signals.

Effect on target catch: 

N/A

Article: 

Reduction technique: 

Bycatch species: 

Field Study

Study Type: 

wild

Location: 

North Carolina

Target catch: 

Spanish mackerel

Effect on bycatch species: 

Dolphins were less likely to interact with gillnets and more likely to echolocate

Effect on target catch: 

No effect

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Study Type: 

wild

Location: 

Baltic sea

Target catch: 

Salmon

Effect on bycatch species: 

Reduced depredation of salmon traps by grey seals (Halichoerus grypus)

Effect on target catch: 

Increased target catch and reduced seal damage to the catch

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Results of the 1986-87 California sea lion-steelhead trout predation control program at the Hiram M. Chittenden Locks. NWAFC Processed Report 88-30, Alaska Fisheries Science Center, NMFS, NOAA, Seattle, Washington.

Study Type: 

wild

Location: 

Washington State

Target catch: 

Trout

Effect on bycatch species: 

Worked temporarily, then habituation occurred

Article: 

Bycatch species: 

Reduction technique: 

Field Study 118

Study Type: 

wild

Location: 

Canada

Target catch: 

n/a

Effect on bycatch species: 

No porpoises were sighted within 200 m of AHD

Effect on target catch: 

n/a

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

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