Effectiveness: Do pingers work?
Various species of cetaceans react to acoustic alarms, and initial experiments with dolphins in captivity found that sounds are much more effective than visual cues (Culik et al. 2001, Evans et al. 1977, Kastelein et al. 2000, Kastelein et al. 2001, Laake et al. 1998).
Acoustic alarms affect cetacean behavior, but do they reduce bycatch? In cooperation with fishermen, researchers have focused on determining whether animals avoid pingers and whether nets with pingers catch fewer cetaceans. In several independent controlled experiments, bycatch was reduced in nets with active pingers (Barlow and Cameron 2003, Bordino et al. 2002, Kraus et al. 1997, Gearin et al. 2000). Other studies have found that harbor porpoises and Hector's dolphins appear to avoid areas with pingers (Stone et al. 1997, Culik et al. 2001).
However, each species is different. For example, dall's porpoises are capable of avoiding nets under favorable conditions yet it is still unclear whether acoustic deterrents work for this species (Hatakeyama et al. 1994, DeAlteris et al. 1996). Pinger effectiveness should be monitored for particular fisheries and species to ensure successful implementation.
Acoustic alarms affect cetacean behavior, but do they reduce bycatch? In cooperation with fishermen, researchers have focused on determining whether animals avoid pingers and whether nets with pingers catch fewer cetaceans. In several independent controlled experiments, bycatch was reduced in nets with active pingers (Barlow and Cameron 2003, Bordino et al. 2002, Kraus et al. 1997, Gearin et al. 2000). Other studies have found that harbor porpoises and Hector's dolphins appear to avoid areas with pingers (Stone et al. 1997, Culik et al. 2001).
However, each species is different. For example, dall's porpoises are capable of avoiding nets under favorable conditions yet it is still unclear whether acoustic deterrents work for this species (Hatakeyama et al. 1994, DeAlteris et al. 1996). Pinger effectiveness should be monitored for particular fisheries and species to ensure successful implementation.
Pinger Research By Species, Fishery, And Region
| SPECIES | REGION and FISHERY | RESULT | AUTHOR/DATE |
| Mixed group of cetaceans | United StatesDrift gillnet for swordfish and sharks (California) | 4-fold decrease in entanglement | Barlow and Cameron 2003 |
| Bottlenose dolphin Tulsiops truncatus | South Africa Nets for shark (KwaZulu-Natal) | Dolphins did not show aversion but were alerted to presence of nets | Peddemors 2000 |
| Common dolphin Delphinus delphis | Experiment in captivity | Dolphins showed aversion to 20kHz acoustic pinger with longer-lasting effect compared to visual cues | Evans et al. 1977 |
| Franciscana dolphin Pontoporia blainvillei | Argentina Artisanal gillnet | Bycatch reduced dramatically (7 dolphins w/pinger, 45 w/o) | Bordino et al. 2002 |
| Harbor porpoise Phocoena phocoena | Canada Surface gillnet (Clayoquot Sound, Vancouver Island) | Porpoises avoided pinger net with significant results | Culik et al. 2001 |
| Harbour porpoise Phocoena phocoena | United StatesBottom-set gillnet for salmon(Washington) | Bycatch reduced significantly | Gearin et al. 2000 |
| Harbour porpoise Phocoena phocoena | Canada Net pens for salmon with anti-seal pingers (Bay of Fundy) | Porpoises were Also deterred, may lose habitat due to aquaculture | Johnston 2002 |
| Harbour porpoisePhocoena phocoena | United States (Jeffreys Ledge, Falmouth, Massachusetts) | Unclear - "pingers work" but details of experiment not described | MacKinnon 1995 |
| Harbour porpoise Phocoena phocoena | United States Driftnet for swordfish (Northeast Atlantic) | Unclear - bycatch reduced but 70 of 150 pingers leaked and failed | Avila 1996 |
| Harbour porpoise Phocoena phocoena | Sweden Bottom-set gillnet for cod(Skagerrak Sea) | Unclear - no bycatch in either control or pinger nets | Carlstroem et al. 2002 |
| Hector's dolphin Cephaloryhnchus hectori | New Zealand Gillnet | Dolphins avoided areas with active pingers, similar to harbor porpoise | Stone et al. 1997 |
| Humpbacked dolphin Sousa chinensis | South Africa Nets for shark (Richards Bay and KwaZulu-Natal south coast) | Details not reported | Dudley et al. 1998 |
| Humpbacked dolphin Sousa chinensis | South Africa Nets for shark(KwaZulu-Natal) | Dolphins did not show aversion but were alerted to presence of nets | Peddemors 2000 |
| Short-beaked common dolphin Delphinus delphis | United States Drift gillnet for swordfish and sharks (California) | 12-fold decrease in entanglement, 4-fold decrease for other cetaceans | Barlow and Cameron 2003 |
| Sperm whale Physeter catodon | Field observation near hydrophone array | Whales ceased sound production for 2 minutes or more when passing pingers | Watkins and Schevill 1975 |
Are There Side Effects On Fish Catch?
Most fish do not respond to pingers. Herring (and fish in the same family, Clupeidae) can hear high-frequency sound, but they do not always react to pingers. Under varying conditions, nets with pingers caught more Atlantic herring and Redeye round herring, less Atlantic herring or the same amount of herring as unadorned nets (Culik et al. 2001, Aitken et al. 2000, Kraus et al. 1997)
However, pingers had no effect on catches of most fish, including:
However, pingers had no effect on catches of most fish, including:
- Atlantic Cod (Gadus morhua)
- Pollock (Pollachius virens)
- Silver hake (Merluccius bilinearis)
- Broadbill swordfish (Xiphias gladius)
- Thresher shark (Alopius vulpinas)
- Shortfin mako shark (Isurus oxyrinchus)
Seals, Sea Lions and Pingers
Like cetaceans, seals and sea lions (pinnepeds) are sometimes attracted to the same fish as gillnet fishermen. Do pingers repel or attract these animals? Again, each species is a little different.
Gillnets with pingers caught fewer California sea lions, northern elephant seals and other pinnepeds during a recent long-term study (Barlow and Cameron 2003). However, another study found that sea lions (Otaria flavescens) appeared increasingly attracted to pingers over time (Bordino et al. 2002).
Neither bycatch of harbour seals (Phoca vitulina) nor their consumption of salmon seem affected by acoustic alarms (Gearin et al. 2000, Kraus et al. 1997).
Gillnets with pingers caught fewer California sea lions, northern elephant seals and other pinnepeds during a recent long-term study (Barlow and Cameron 2003). However, another study found that sea lions (Otaria flavescens) appeared increasingly attracted to pingers over time (Bordino et al. 2002).
Neither bycatch of harbour seals (Phoca vitulina) nor their consumption of salmon seem affected by acoustic alarms (Gearin et al. 2000, Kraus et al. 1997).
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