Cetacean bycatch
Cetacean bycatch (or cetacean by-catch) is the
Cetacean bycatch is increasing in intensity and frequency.
Bycatch trends
Generally cetacean bycatch is on the increase. Most of the world's cetacean
While gillweed nets are a principal concern, other types of nets also pose a problem:
However, the tuna industry has achieved successes in reversing cetacean bycatch trends. International recognition of the problem of cetacean bycatch in tuna fishing led to the Agreement on the International Dolphin Conservation Program in 1999 and overall there has been a dramatic reduction in death rates.[6] In particular, dolphin bycatch in tuna fishing in the East Tropical Pacific has dropped from 500,000 per year in 1970 to 100,000 per year in 1990 to 3,000 per year in 1999 to 1,000 per year in 2006.[7]
A
Cetaceans at risk
Bycatch is recognized as a primary threat to all cetaceans. The following cetaceans are at high risk for entanglement in
Atlantic humpback dolphins
The
Baleen whales
Burmeister's porpoises
The Burmeister's porpoise (Phocoena spinipinnis) is one of three cetaceans that are most often bycaught in Peru and Chile.[13] Several thousand porpoises are caught each year in Peru alone.[13] Bycatch is a frequent occurrence for this species because of the inability to detect them in the water. Surveys have shown that bycatch remains a concern in that area today and it is unknown whether or not the population is declining.[13] Data, conservation measures and awareness are lacking. These porpoises are cryptic making surveying a challenge.[13] It is also difficult to estimate bycatch because the sale of porpoise meat is no longer available at markets.
Commerson's dolphins
The expanding trawl fisheries devastated the
La Plata dolphins
The La Plata or Franciscana dolphin (Pontoporia blainvillei) is the most threatened small cetacean in the southwest Atlantic Ocean due to bycatch.[13] They are only found in the coastal waters of Argentina, Brazil, and Uruguay.[15] This species has been divided into four ranges (FMU's: Franciscana Management Units) for management and conservation purposes. These populations are genetically different. Mortality rates are 1.6% for FMU 4 and 3.3% for FMU 3 but it is unknown whether these estimates are accurate.[13] Aerial surveys have proven inconclusive so far as to the population numbers of franciscanas. To rectify this situation, more surveys are needed as well as political commitment, awareness campaigns and bycatch mitigation techniques.
Harbour porpoises
There is substantial incidental catches in fishing operations.
Hector's and Maui's dolphins
In
Indo-Pacific humpback and bottlenose dolphins
Irrawaddy dolphins
Based on a survey in 2001, fewer than 70
Spinner and Fraser's dolphins
In the
Yangtze River dolphins and finless porpoises
The Yangtze River or
Vaquita
The vaquita (Phocoena sinus) is highly endangered and is endemic to the upper Gulf of California, Mexico. They are killed in both gillnets and trawl nets from commercial and artisanal fishing. As of 2004 there are less than 100 vaquitas left in the Gulf of California.[15]
Mitigating bycatch
Acoustic deterrent devices
The use of acoustic alarms to mitigate by-catch and also to protect aquaculture sites has been proposed but has advantages and risks associated with the alarms.
Barium sulfate
A promising
Fishing regulations and management
Management and regulation are lacking in many
In the U.S. the
Temporary closure
Temporary closure of fisheries during the short period of the year when cetaceans are migrating through the area would decrease bycatch significantly.[31]
Observers on boat
Observers are on fishing vessels spotting cetaceans in the water so that they can be avoided.[32]
In the U.S.
Some programs like Earth Island Institute's Dolphin Safe Label certification claim to require certification from onboard observers. However, the only fishery in the world where independent scientific observers certify whether or not a dolphin has been harmed is the Eastern Tropical Pacific, home to the AIDCP Treaty program. For all other tuna fisheries of the world, the efficacy of onboard observer certification has come under increasing scrutiny as such programs have proven indefensible or unmanageable: [33]
In an interview with Radio Australia last year, Mark Palmer of EII confirmed that it is mostly the case that EII monitors do not go on board of the vessels, and their organization does not have the kind of resources to put observers on the "many thousands" of ships that are out there catching tuna.[34]
Additionally, environmental groups have criticized Earth Island Institute's support of U.S. policies that do not require independent, on-board observation and instead only rely on self-certification by fishing captains, and that even where they may at some point in the future require independent observers, the lack of uniformity in tracing and verifying certifications in different countries means non-certified products can become certified if they are simply taken to the right port.[35]
Other ways of mitigating bycatch
- Implement gear technology (changes in fishing gear and practices) documented to mitigate cetacean bycatch[36]
- Buy tuna and other seafood that has a dolphin safe label.
- Buy Sustainable seafood. To find out which seafood is produced sustainably (i.e. using cetacean friendly gear), refer to World Wildlife Fund Global to access worldwide sustainable seafood guides[37]
- Support sustainable seafood companies and restaurants[38]
- Raise international awareness to assess, monitor and mitigate bycatch problems[39]
- Create legislation on responsible fishing practices.[39]
- Develop and promote industry adoption of "Best Practice Guidelines" for fishing operations[39]
References
- ^ Alverson et al. (1994)
- ^ Demaster et al. (2001)
- ^ a b c d e f g h i Read et al. (2006)
- ^ Silvani et al. (1999)
- ^ Miragliuolo et al. (2002)
- ^ "International Affairs | NOAA Fisheries". 25 August 2021.
- ^ "The Tuna-Dolphin Issue". 22 November 2021.
- ^ https://www.news.com.au/technology/science/animals/aussie-shark-population-is-staggering-decline/news-story/49e910c828b6e2b735d1c68e6b2c956e Aussie shark population in staggering decline. Rhian Deutrom. December 14, 2018. Retrieved December 26, 2018.
- ^ a b http://www.afd.org.au/news-articles/queenslands-shark-control-program-has-snagged-84000-animals Action for Dolphins. Queensland’s Shark Control Program Has Snagged 84,000 Animals. Thom Mitchell. November 20, 2015. Retrieved December 26, 2018.
- ^ https://web.archive.org/web/20181002102324/https://www.marineconservation.org.au/pages/shark-culling.html "Shark Culling". marineconservation.org.au. Archived from the original on 2018-10-02. Retrieved December 26, 2018.
- ^ https://hsi.org.au/blog/separating-fact-from-fiction-in-qlds-shark-culling-program Separating fact from fiction in QLD’s shark culling program. Nicola Beynon. October 19, 2018. Retrieved December 26, 2018
- ^ http://www.sharkangels.org/index.php/media/news/157-shark-nets "Shark Nets". sharkangels.org. Retrieved December 26, 2018.
- ^ a b c d e f g h i j k l m n o p q r Reeves et al. (2005)
- ^ Knowlton (2003)
- ^ a b c d e f g WWF (2004)
- ^ Hammond et al. (2002)
- ^ Jefferson & Curry (1994)
- ^ a b Caswell et al. (1998)
- ^ Kastelein et al. (1999)
- ^ Kraus et al. (1997)
- ^ Gearin et al. (2000)
- ^ Trippel et al. (2003)
- ^ Larsen (1997)
- ^ Reeves et al. (1996)
- ^ a b Barlow & Cameron (2003)
- ^ Culik et al. (2001)
- ^ Boughton et al. (2005)
- ^ Mooney et al (2004)
- ^ Mooney et al (2007)
- ^ Trippel et al (2008)
- ^ Murray et al.(2000)
- ^ Animal Freedom (2008)
- ^ "The fairy tale of US "dolphin safe" labeling False claims, unintended consequences" (PDF). July 1, 2012. Retrieved January 9, 2014.
- ^ "EII On-board Observers, Ghosts?". July 1, 2012. Archived from the original on January 7, 2014. Retrieved January 9, 2014.
- ^ "Trade Dispute With Mexico Over 'Dolphin-Safe' Tuna Heats Up". NPR.org. July 1, 2012. Retrieved January 9, 2014.
- S2CID 83811349.
- ^ "Sustainable Seafood: Consumer Guides", World Wildlife Fund Global 2013
- ^ "Seafood Watch" Archived January 19, 2013, at the Wayback Machine, Monterey Bay Aquarium 2013
- ^ a b c Fishing Technology Service (2008)
General references
- Alverson, DL, Freeburg, MH, Murawski, SA and JG Pope (1994). A global assessment of fisheries bycatch and discards. Fisheries Technical Paper. Food and Agriculture Organization, Rome. 339 pp.
- Animal Freedom (2008) Cetacean Bycatch
- Barlow, J & Cameron, GA (2003). Field experiments show that acoustic pingers reduce marine mammal bycatch in the Californian drift gill net fishery. Marine Mammal Science. 19: 265-283.
- Boughton, DA, Fish, H, Pipal, K, Goin, J, Watson, F, Casagrande, J, and M Stoecker (2005). Contraction of the southern range limit for anadromous Oncorhynchus mykiss. NOAA Technical Memorandum NMFS. NOAA-TM-NMFS-SWFSC-380. U.S. Department of Commerce.
- Caswell, H, Brault, S, Read, AJ, and TD Smith (1998). Harbour porpoise and fisheries: an uncertain analysis of incidental mortality. Ecological Applications. 8(4): 1226–1238.
- Culik, BM, Koschinski, S, Tregenza, N, and GM Ellis (2001). Reactions of harbour porpoises Phocoena phocoena and herring Clupea harengus to acoustic alarms. Marine Ecology Progress Series. 211: 155-260.
- Demaster, DJ, Fowler, CW, Perry, SL, and ME Richlen (2001). Predation and competition: the impact of fisheries on marine mammal populations over the next one hundred years. Journal of Mammalogy. 82: 641-651.
- Fishing Technology Service (2008) Managing bycatch and reducing discards: Taking it to the next level
- Gearin, PJ, Gosho, ME, Laake, JL, Cooke, L, DeLong, R, and KM Hughes (2000). Experimental testing of acoustic alarms (pingers) to reduce bycatch of harbor porpoise, Phocoena phocoena, in the state of Washington. Journal of Cetacean Research and Management. 2:1-9.
- Hammond, PS, Berggren, P, Benke, H, Borchers, DL, Collet, A, Heide-Jorgensen, MP, Heimlich, S, Hiby, AR, Leopold, MF, and N Oien (2002). Abundance of harbour porpoise and other cetaceans in the North Sea and adjacent waters. Journal of Applied Ecology. 39: 361-376.
- Jefferson, TA and Curry, BE (1994). A global review of porpoise (Cetacea: Phocoenidae) mortality in gill nets. Biological Conservation. 67(2): 167-183.
- Kastelein, RA, Au, WWL, and de Haan, D (1999). Detection distances of bottom-set gillnets by harbour porpoises (Phocoena phocoena) and bottlenose dolphins (Tursiops truncates). Marine Environmental Research. 49(4): 359-375.
- Knowlton, AR et al. (2003). Analysis of scarring on North Atlantic right whales (Eubalaena glacialis): monitoring rates of entanglement interaction. Final report. Northeast Fisheries Science Center, Woods Hole, Massachusetts.
- Kraus, S, Read, AJ, Solow, A, Baldwin, K, Spradlin, T, Anderson, E, and J Williamson (1997). Acoustic alarms reduce porpoise mortality. Nature. 388:525.
- Larsen, F (1997). Effekten af akustiske alarmer pa bifangst as marsvin i garn. Report number 44-97 (unpublished). Available from the Danish Institute for Fisheries Research, Jaegersborgvei 64-66, DK- 2800 kg. Lyngby, Denmark.
- Miragliuolo, A, Mussi, B, and G Bearzi (2002). Observations of driftnetting off the island of Ischia, Italy, with indirect evidence of dolphin bycatch. European Cetacean Research. 4pp.
- Monterey Bay Aquarium (2013) Seafood Watch Archived 2013-02-25 at the Wayback Machine
- Mooney, TA, Nachtigall, P and Au, WWL, (2004). "Target strength of a nylon monofilament and an acoustically enhanced gillnet: predictions of biosonar detection ranges."[permanent dead link] Aquat. Mamm., 30: 220-26.
- Mooney, TA, Au, WWL, Nachtigall, P, and Trippel, EA (2007). "Acoustic and stiffness properties of gillnets as they relate to marine mammal bycatch." ICES J. Mar. Sci., 64: 1324–32.
- Murray, KT, Read, AJ, and AR Solow. 2000. The use of time/area closures to reduce bycatches of harbour porpoises: lessons from the Gulf of Maine sink gillnet fishery. Journal of Cetacean Research and Management. 2(2): 135-141.
- Read, AJ, Drinker, P, and S Northridge (2006). Bycatch of marine mammals in the U.S. and Global Fisheries. Conservation Biology. 20(1): 163-169.
- Reeves, RR, Hofman, RJ, Silber, GK, and D Wilkinson (1996). Acoustic deterrence of harmful marine mammal-fishery interactions. Proceedings of a workshop held in Seattle, Washington, 20–22 March 1996. U.S. Department of Commerce, NOAA Technical Memorandum, NMFS-OPR-10 (unpublished). 70 pp. Available from the NMFS Office of Protected Resources, 1335 East/ West Highway, Silver Springs, MD. 20910, USA.
- Reeves, RR, Berggren, P, Crespo, EA, Gales, N, Northridge, SP, Sciara, GND, Perrin, WF, Read, AJ, Rogan, E, Smith, BD, and KV Waerebeek (2005). Global priorities for reduction of cetacean bycatch. WWF document. 27 pp.
- Silvani, L, Gazo, JM, and A Aguilar (1999). Spanish driftnet fishing and incidental catches in the western Mediterranean. Biological Conservation. 90: 79-85.
- Trippel, EA, Strong, MB, Terhune, JM, and JD Conway (1999). "Mitigation of harbour porpoise (Phocoena phocoena) by-catch in the gillnet fishery in the lower Bay of Fundy." Canadian Journal of Fisheries and Aquatic Science, 56: 113-123.
- Trippel, EA, Holy, NL, and Shepperd, TD, (2008). "Barium sulphate modified fishing gear as a mitigative measure for cetacean incidental mortalities." J. Cetacean Res. Manage., 10(3):235–246.
- World Wildlife Fund Global (2013). Sustainable Seafood: Consumer Guides
Further reading
- Baird, RW and Guenther, TJ (1995). Account of harbour porpoise (Phocoena phocoena) strandings and bycatches along the coast of British Columbia. Reports of the International Whaling Commission Special Issue. 16: 159-168.
- Cox, TM, Read, AJ, Swanner, D, Urian, K and D Waples. 2004. Behavioural responses of bottlenose dolphins, Tursiops truncatus, to gillnets and acoustic alarms. Biological Conservation. 115: 203-212.
- Cox, TM, Read, AJ, Solow, A and N Tregenza. 2001. Will harbour porpoises (Phocoea phocoena) habituate to pingers? Journal of cetacean Research and Management. 3: 81-86.
- Donovan, GP. 1994. Developments on issues relating to the incidental catches of cetaceans since 1992 and the UNCED conference. Report of the IWC (Special Issue). 15: 609-613.
- Guenther, TJ et al. (1993). Cetacean strandings and entanglement in fishing gear on the west coast of Canada during 1992. IWC Document SC/45/O 4. 1-7 pp.
- Guenther (1995) Guenther, TJ et al. (1995). Strandings and fishing gear entanglements of cetaceans off the west coast of Canada in 1994. IWC Document SC/47/O 6. 1-7 pp.
- Hail, MA. 1998. An ecological view of the tuna-dolphin problem: impacts and trade-offs. Reviews in Fish Biology and Fisheries. 8: 1-34.
- Kuiken, T, Simpson, VR, Allchin, CR, Bennett, PM, Codd, GA, Harris, EA, Howes, GJ, Kennedy, S, Kirkwood, JK, Law, RJ, Merrett, NR and S Phillips. 1994. Mass mortality of common dolphins (Delphinus delphis) in south west England due to the incidental capture in fishing gear. The Veterinary Record. 134: 81-89.
- Lewison, RL, Crowder, LB, Read, AJ and SA Freeman. 2004. Understanding impacts of fisheries bycatch on marine megafauna. Trends in Ecology & Evolution 19: 598-604.
- Lopez, A, Pierce, GJ, Santos, MB, Gracia, J and A Guerra. 2003. Fishery by-catches of marine mammals in Galician waters: results from on-board observations and an interview survey of fishermen. Biological Conservation. 111: 25-40.
- Morizur, Y, Berrow, SD, Tregenza, NJC, Couperus, AS and S Pouvreau. 1999. Incidental catches of marine mammals in pelagic trawl fisheries of the northeast Atlantic. Fisheries Research. 41: 297-307.
- Wade, PR. 1998. Calculating limits to the allowable human-caused mortality of cetaceans and pinnipeds. Marine Mammal Science. 14: 1-37.
- Zerbini, AN, and JE Kotas. 1998. A note on cetacean bycatch in pelagic driftnetting off southern Brazil. Report of the IWC. 48: 519-524.
External links
External videos | |
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Saving a humpback whale from fisherman's nets – YouTube |
- Project GLOBAL: Global Bycatch Assessment of Long-Lived Species project
- European Cetacean Bycatch Campaign
- Cetacean Bycatch Resource Center
- WWF Species Programme (2004) Cetacean bycatch and the IWC
- EIA reports on cetaceans & bycatch: Up to date info.
- EIA in the USA: Up to date info.
- Sea Anglers Conservation Network press release on cetacean bycatch
- Newspaper article describes an ensnared whale who seemingly thanked her rescuers
- Scientists rank endangered dolphins and porpoises most in need of immediate action
- A WWF Press Release about bycatch
- A cetacean bycatch web page by Animal Freedom
- New project will tackle whale entanglement, article by Environmental News Service
- Learn about sustainable seafood and the Sustainable Seafood Guide