Small Cetaceans (maximum length < 7.5 meters)

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: 

Field Study 772

Study Type: 

wild

Location: 

Queensland, Australia

Target catch: 

Sharks

Effect on bycatch species: 

Dolphins heard the F3 pinger 45 m from the net, they could only detect the F10 pinger less than 40 m from the net

Effect on target catch: 

None reported

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Field Study

Study Type: 

wild

Location: 

Crozet Islands

Target catch: 

Patagonian toothfish

Effect on bycatch species: 

Less time for interaction with longlines

Effect on target catch: 

Less depredation

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Field Study 756

Study Type: 

wild

Location: 

Cornwall

Target catch: 

None reported

Effect on bycatch species: 

There was a significant difference in the number of porpoise clicks between nets with and without pingers, but the extent of displacement could not be determined. No evidence of habituation to the pingers.

Effect on target catch: 

None reported

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

Field Study

Study Type: 

summary

Location: 

Hawaii

Effect on bycatch species: 

Initially disrupted false killer whale's echolocation performance capabilities

Article: 

Bycatch species: 

Fishing Gear: 

Reduction technique: 

Field Study

Study Type: 

wild

Location: 

Australia

Target catch: 

Albacore tuna, yellowfin tuna, mahi mahi

Effect on bycatch species: 

No cetaceans were caught on experimental lines

Effect on target catch: 

No effect

Article: 

Bycatch species: 

Reduction technique: 

Fishing Gear: 

South Asian River Dolphin

Species: 

Platanista gangetica

Type: 

Mammal

Distribution: 

Indus River, Ganges-Brahmaputra-Meghna, and Karnaphule-Sangu river systems of the Indian subcontinent

Population: 

Low thousands

Bycatch Threat: 

Gillnets, longlines

IUCN Status: 

Endangered

The South Asian river dolphin is divided into two subspecies, one inhabiting the Indus River of Pakistan (Indus River dolphin - Platanista gangetica minor) and the other the Ganges and associated river systems in India and Nepal (Ganges River dolphin - Platanista gangetica gangetica); a subpopulation of P. gangetica gangetica is also found in the Karnaphuli and Sangu Rivers of Bangladesh. Ganges River dolphins reside in the Sundarbans mangrove forest (India and Bangladesh) as well.

Irrawaddy Dolphin

Species: 

Orcaella brevirostris

Type: 

Mammal

Distribution: 

Estuarine and freshwater habitats of the tropical and subtropical Indo-Pacific; also found in coastal waters of this region

Population: 

Decreasing

Bycatch Threat: 

Gillnets, driftnets

IUCN Status: 

Vulnerable, with five Critically Endangered subpopulations

The principal threat to the Irrawaddy dolphin throughout much of its range is accidental entanglement in gillnets (Smith et al 2007). Freshwater populations of the species are at the most risk, particularly those inhabiting the Mekong River (Cambodia, Lao PDR, Vietnam), the Mahakam River (Indonesia), the Ayeyarwaddy River (Myanmar), and lakes Chilika (India) and Songkhla (Thailand). These areas are considered high-use habitat due to their biological productivity, and there is frequently overlap between dolphin populations and gillnet fisheries (Smith et al 2006).

Chilean Dolphin

Species: 

Cephalorhynchus eutropia
Photo: Sonja Heinrich
Photo: Sonja Heinrich

Type: 

Mammal

Distribution: 

Along the Chilean coast in cold, shallow waters; sometimes enters rivers & estuaries

Population: 

Low thousands

Bycatch Threat: 

Gillnets, anti-predator nets, pots and traps

IUCN Status: 

Near Threatened

Historically, the Chilean dolphin has been hunted both for food and for crab bait (Reeves et al 2008). Although cetaceans are now protected by law in Chile (Torres et al 1979), regulation enforcement is virtually nonexistent and temptation is high for impoverished fishermen to supplement their income by killing dolphins for bait (Dawson 2009; Reeves et al 2008).

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