Pinnipeds

Seal exclusion devices in cod pots prevent seal bycatch and affect their catchability of cod

Study Type: 

wild

Location: 

Swedish coast

Target catch: 

Cod

Effect on bycatch species: 

Reduced sea bycatch to zero

Effect on target catch: 

Oval shaped SEDs and ones with larger rectangle opening increased catchability of pots

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The impact of predation by marine mammals on Patagonian toothfish longline fisheries

Study Type: 

wild

Location: 

South Georgia

Target catch: 

Patagonian toothfish

Effect on bycatch species: 

Sperm whales interacted with longlines 25% of the time; orcas interacted only 5% of the time could remove half of the catch; fur seal interactions have declined since 2009

Effect on target catch: 

Catch rates were lower when marine mammals were present

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Field Study

Study Type: 

wild

Location: 

California

Target catch: 

Swordfish and thresher shark

Effect on bycatch species: 

Decreased cetacean bycatch and no habituation. Pinniped bycatch was not significantly different

Effect on target catch: 

n/a

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Australian sea lion

Species: 

Neophoca cinerea
Photo: Brian M. Hunt
Photo: Brian M. Hunt

Type: 

Mammal

Distribution: 

Southern and southwestern Australian waters

Population: 

~14700

Bycatch Threat: 

Gillnets, trawls, traps and pots

IUCN Status: 

Endangered

The Australian sea lion population decreased due to harvests in the 17th and 18th centuries and traditional subsistence hunting by aborigines (Goldsworhty & Gales 2008). Isolated reports of deliberate killings have persisted into the 21st century as well (DEWHA 2010). Although the species is now protected by Australian law throughout its range, recovery towards pre-sealing levels has been minimal (Goldsworthy and Gales 2008; AFMA 2010).

Mediterranean Monk Seal

Species: 

Monachus monachus
Photo: © IFAW/R. McLanaghan
Photo: © IFAW/R. McLanaghan

Type: 

Mammal

Distribution: 

Isolated colonies in the Aegean and Ionian Seas, and in the eastern North Atlantic from Morocco to Cap Blanc

Population: 

350-450

Bycatch Threat: 

Gillnets, trammel nets, ghost nets, bottom-set long lines

IUCN Status: 

Critically Endangered

The once-abundant Mediterranean monk seal has been adversely impacted by human activities, ranging from exploitation for fur and oil to habitat fragmentation that have occured over many centuries. Today, one of the greatest threats facing the remaining seals is accidental entanglement in fishing nets. Bycatch mortality occurs throughout the species' range, and has been increasingly problematic since the 1980s (Guclusoy et al 2004).

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