Cetacean bycatch 1642133 225360452 2008-07-13T07:54:18Z Geronimo20 332930 update template {{fishery reporting topics}} [[Image:Fraser s group.jpg.jpeg|thumb|left|200px|Group of [[Fraser's dolphin]]s.]] '''Cetacean bycatch''' is the [[by-catch|incidental capture]] of non-target [[cetacean]] [[species]] by [[fishery|fisheries]]<ref name=Alverson (1994)>Alverson et al (1994)</ref>. Species which are seriously affected by this include [[dolphin]]s, [[porpoise]]s, and [[whale]]s. [[Bycatch]] can be caused by entanglement in [[fishing net]]s and [[fishing line|lines]], or direct capture by [[Fish hook|hooks]] or in [[Trawling|trawl nets]]. Cetacean bycatch is increasing in intensity and frequency.<ref name=Demaster (2001)>Demaster et al (2001)</ref> This is a trend that is likely to continue because of increasing [[Population growth#Human population growth rate|human population growth]] and demand for marine food sources, as well as industrialization of [[fisheries]] which are expanding into new areas. These fisheries come into direct and indirect contact with cetaceans. An example of direct contact is the physical contact of cetaceans with [[fishing net]]s. Indirect contact is through marine trophic pathways where fisheries are severely reducing fish stocks that cetaceans rely on for food. In some fisheries, cetaceans are captured as bycatch but then retained because of their value as food or [[Bait fish|bait]].<ref name=Read (2006)>Read et al (2006)</ref> In this fashion, cetaceans can become a target of fisheries. ==Bycatch is increasing== [[Image:Entangled porpoise.jpg|right|thumb|A [[Dall's Porpoise]] caught in a fishing net]] Most of the world’s cetacean [[bycatch]] occurs in [[gillnet]] fisheries.<ref name=Read (2006)/> The mean annual bycatch in the U.S. alone from 1990-1999 was 6,215 marine mammals, with dolphins and porpoises being the primary cetaceans caught in gill nets.<ref name=Read (2006)/> A study by Read et al<ref name=Read (2006)/> estimated global bycatch through observation of U.S. fisheries and came to the conclusion that an annual estimate of 653,365 marine mammals, comprising 307,753 cetaceans and 345,611 [[pinniped]]s were caught from 1990-1994. While gill-nets are a principle concern, other types of nets also pose a problem: [[Trawling|trawl nets]], [[Seine (fishing)#Purse seine|purse seines]], beach seines, [[longline]] gear, and [[driftnet]]s. Driftnets are known for high rates of bycatch and they affect all cetaceans and other marine species.<ref name=Silvani (1999)>Silvani et al (1999)</ref> They are fatal for small [[toothed whale]]s (''Odontocetes'') and [[sperm whale]]s, as well as other marine mammals and fish such as [[shark]]s, [[sea bird]]s and [[sea turtle]]s. Many fisheries routinely use driftnets exceeding the EU size limit of 2.5 km/boat.<ref name=Miragliuolo (2002)>Miragliuolo et al (2002)</ref> This illegal drift-netting is a major issue, especially in important feeding and breeding grounds for cetaceans. Cetaceans have become the bane of many long-line fishermen in areas where certain whale populations have made a significant comeback in recent years. Whales often follow the boats, devouring the catch and leaving little more for them than fish heads when it is hauled in. <!-- Deleted image removed: [[Image:6144.jpg|thumb|Greenpeace observers pull in dead dolphin bycatch]] --> ==Cetaceans at risk== Bycatch is recognized as a primary threat to all cetaceans. The following cetaceans are at high risk for entanglement in [[gillnet]]s: ====Atlantic humpback dolphins==== The [[Atlantic humpback dolphin]] (''Sousa teuszii'') is endemic to West Africa. Several stocks have been identified with numbers ranging from tens to a few hundred.<ref name=Reeves (2005)>Reeves et al (2005)</ref> Abundance estimates are lacking. Gaps in the species range and hence distribution is evident. Bycatch is only documented in a few West African countries. Surveys and evaluations need to be conducted to determine the presence/ absence of humpback dolphins in their historical range. Conservation measures need to be implemented to save this species. Because many people live off the sea, it is not feasible to have complete gillnet closures. Some areas may be designated as off-limits to gillnet fisheries. [[Eco-tourism]] may be implemented successfully because of high [[species diversity]].<ref name=Reeves (2005)/> ====Baleen whales==== [[Image:Eubalaena glacialis with calf.jpg|thumb|right|North Atlantic Right Whale mother and calf.]] [[Baleen whale]]s, ''Mysticeti'', are often taken in gill-nets and in fisheries that use vertical lines to mark traps and pots.<ref name=Read (2006)/> Large cetaceans such as humpback and right whales may carry off gear after entanglement. This explains the large scars borne by whales along the U.S. Atlantic coast.<ref name=Knowlton (2003)>Knowlton (2003)</ref> Analyses show that 50-70% of [[Gulf of Maine]] [[humpback whales]], ''Megaptera novaeangliae'', and [[North Atlantic Right Whale]], ''Eubalaena glacialis'', have been entangled at least once in their lifetime.<ref name=Read (2006)/> The north Atlantic right whale is one of the most endangered large cetaceans and only 300-350 individuals remain.<ref name=WWF (2004)>WWF (2004)</ref> [[Minke Whales]], ''Balaenoptera acutorostrata'', are also at risk. ====Burmeister’s porpoises==== The [[Burmeister's porpoise]] (''Phocoena spinipinnis'') is one of three cetaceans that are most often bycaught in [[Peru]] and [[Chile]].<ref name=Reeves (2005)/> Several thousand porpoises are caught each year in Peru alone.<ref name=Reeves (2005)/> 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.<ref name=Reeves (2005)/> Data, conservation measures and awareness are lacking. These porpoises are [[Crypsis|cryptic]] making surveying a challenge .<ref name=Reeves (2005)/> It is also difficult to estimate bycatch because the sale of porpoise meat is no longer available at markets. ====Commerson’s dolphins==== [[Image:Commdolph01.jpg|thumb|right|A Commerson's Dolphin in an aquarium.]] The expanding trawl fisheries devastated the [[Commerson's dolphin]] (''Cephalorhynchus commersonii'') populations in [[Patagonia]]. Trawl fisheries greatly expanded for twenty years until they crashed in 1997.<ref name=Reeves (2005)/> [[Pelagic zone|Pelagic]] [[squid]] [[fisheries]] took over which use [[Midwater trawling|pelagic trawls]] that are harmful to dusky, short-beaked common dolphins, and Commerson’s dolphins. There are approximately 21,000 Commerson’s dolphins remaining today.<ref name=Reeves (2005)/> Two stocks have been identified in the population but [[genetic]] information and bycatch levels are unknown. With [[anchovy]] fisheries expanding, it is imperative to assess the Commerson’s dolphin population before these fisheries grow. The seasonal operation of in-shore gillnet fisheries are known to involve bycatch of cetaceans. Presently, there are no known estimates of gillnet bycatch. The bycatch problem in [[Argentina]] is political in nature.<ref name=Reeves (2005)/> Improvements in fishing technology, awareness, and a large scale survey of Commerson’s dolphin populations and the impact of bycatch is essential. ====La Plata dolphins==== The [[La Plata Dolphin|La Plata]] or Franciscana dolphin (''Pontoporia blainvillei'') is the most threatened small cetacean in the southwest [[Atlantic Ocean]] due to bycatch.<ref name=Reeves (2005)/> They are only found in the coastal waters of [[Argentina]], [[Brazil]], and [[Uruguay]].<ref name=WWF (2004)/> 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.<ref name=Reeves (2005)/> [[Aerial survey]]s 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.<ref name=Hammond (2002)>Hammond et al (2002)</ref> Often, the [[Harbour Porpoise]] (''Phocoena phocoena'') is killed by incidental by-catch (10, 11, 12). Gillnets pose a serious threat to the harbour porpoise as they are extremely susceptible to entanglement.<ref name=Jefferson (1994)>Jefferson & Curry (1994)</ref> A study by Caswell et al<ref name=Caswell (1998)>Caswell et al (1998)</ref> in the western [[North Atlantic]] combined the mean annual rate of increase of the harbour porpoise with the uncertainty of [[incidental mortality]] and [[Population dynamics of fisheries#Population size|population size]]. It was found that the incidental mortality exceeds critical values and therefore by-catch is a significant threat to the harbour porpoise.<ref name=Caswell (1998)/> Harbour porpoises become entangled in nets due to their inability to detect the nets before collision.<ref name=Kastelein (1999)>Kastelein et al (1999)</ref> In 2001, 80 harbour porpoises were killed in [[salmon]] gillnet fisheries in [[British Columbia]], [[Canada]]. ====Hector's and Maui's dolphins==== [[Image:Hectors Dolphin.jpg|thumb|Hector's dolphins have a unique rounded dorsal fin.]] In [[New Zealand]], these dolphins have a high rate of entanglement. [[Hector's dolphin]] (''Cephalorhynchus hectori'') is endemic to the coastal waters New Zealand and there are about 7,400 in abundance.<ref name=WWF (2004)/> A small population of Hector’s dolphins is isolated on the west coast of the island and have been declared a subspecies called [[Maui's Dolphin]]. Maui's dolphins (''Cephalofhynchus hectori maui'') are often caught in set nets and [[Pair trawling|pair trawlers]] resulting in less than 100 left in the wild.<ref name=WWF (2004)/> For protection, a section of the dolphin’s range on the west coast has been closed to gillnet fisheries. ====Indo-Pacific humpback and bottlenose dolphins==== [[Drift net|Drift]] and bottom-set [[gillnet]]s are the biggest conservation threat to these dolphins in the [[Indian Ocean]]. There have only been assessments in some areas such as [[Zanzibar]]. Hunting up until 1996 reduced the population and contributed to their decline. Now hunting has been replaced with [[eco-tourism]]. It was estimated in 2001 that there are 161 [[bottlenose dolphins]] (''Tursiops aduncus'')] and 71 Indo-Pacific [[Humpback Dolphin]] (''Sousa chinensis'') that are left based on photo-identification mark-recapture techniques.<ref name=Reeves (2005)/> A study on bycatch revealed over 160 incidences of bycatch since 2000. Approximately 30% of bycatch is in drift and bottom-set gillnets.<ref name=Reeves (2005)/> Mortality is about 8% and 5.6% for bottlenose and humpback dolphins respectfully .<ref name=Reeves (2005)/> The mitigation of bycatch is imperative for these species and eco-tourism. ====Irrawaddy dolphins==== Based on a survey in 2001, fewer than 70 [[Irrawaddy dolphin]]s (''Orcaella brevirostris'') left in the upper region of the Malampaya Sound in the [[Philippines]] and 69 individuals in the [[Mekong River]].<ref name=Reeves (2005)/> They have been severely impacted by lift nets, and crab gear and they are critically endangered. It is estimated that mortality from bycatch may be greater than 4.5% in Malampaya Sound and 5.8% in the Mekong River.<ref name=Reeves (2005)/> The population is declining dramatically. Current bycatch levels are unsustainable and bycatch reduction measures as well as long-term systematic monitoring are urgently required. The elimination of gillnets from areas of high use is needed and economic incentives need to be provided to the local people. ====Spinner and Fraser’s dolphins==== [[Image:Spinner dolphins.jpg|thumb|right|Spinner dolphins.]] In the [[Philippine]], [[tuna]] [[driftnet]] [[fisheries]] have a substantial impact on the populations. One tuna fishery alone kills 400 [[Spinner Dolphin]] (''Stenella longirostris'') and [[Fraser's dolphin]]s (''Lagenodelphis hosei'') each year.<ref name=Reeves (2005)/> Round-haul nets are an even greater concern with a bycatch of up to 3000 dolphins per year.<ref name=Reeves (2005)/> Dolphins that are bycaught often end up as shark bait for [[longline]] fisheries. There is not enough data to conclude total bycatch for the Philippines. Initial assessment indicates that bycatch is not sustainable. Monitoring of dolphin populations and fisheries is urgently needed. ====Yangtze River dolphins and finless porpoises==== [[Image:Lipotes_vexillifer.png|thumb|right|Illustration of a Baiji dolphin.]] The Yangtze River or [[Baiji]] dolphin (''Lipotes vexillifer'') is the most endangered cetacean and is only found in the [[Yangtze River]], [[China]]. A survey conducted in 1997 found only thirteen dolphins.<ref name=WWF (2004)/> The Yangtze River [[finless porpoise]] (''Neophocaena phocaenoides asiaeorientalis'') also lives in the Yangtze River. Abundance has declined and there are fewer than 2000 dolphins left.<ref name=WWF (2004)/> This may be due, in part, to the construction of the [[Three Gorges Dam]] which covers a significant amount of the dolphin’s habitat. Both species are often subject to entanglement in gillnets. ====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 fishing|commercial]] and [[Artisan fishing|artisanal fishing]]. There are presently less than 600 vaquitas left in the Gulf of California.<ref name=WWF (2004)/> ==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. Acoustic deterrent devices, or pingers, have reduced the number of cetaceans caught in gill nets. Harbour porpoises have been effectively excluded from bottom-set gill nets during many experiments for instance in the [[Gulf of Maine]] ,<ref name=Kraus (1997)>Kraus et al (1997)</ref> along the [[Olympic Peninsula]],<ref name=Gearin (2000)>Gearin et al (2000)</ref> in the [[Bay of Fundy]],<ref name=Trippel (2003)>Trippel et al (2003)</ref> and in the [[North Sea]].<ref name=Larsen (1997)>Larsen (1997)</ref> All of these studies show up to a 90% decrease in harbour porpoise bycatch. Pingers work because they produce a sound that is aversive (20; 15). There has been a recent re-evaluation of the potential of pingers<ref name=Reeves (1996)>Reeves et al (1996)</ref> and their use in other fisheries due to their growing success. An experiment on the [[California]] drift gill net fishery demonstrated how acoustic pingers reduce marine mammal bycatch.<ref name=Barlow (2003)>Barlow & Cameron (2003)</ref> It was shown that bycatch was significantly reduced for common dolphins and [[sea lion]]s. Bycatch rates were also lower for other cetacean species like the [[Northern right whale dolphin]], [[Pacific white-sided dolphin]], [[Risso’s dolphin]] and [[Dall's Porpoise]]. It is agreed upon that the more pingers on a net, the less bycatch. There was a 12-fold decrease in common dolphin entanglement using a net with 40 pingers.<ref name=Barlow (2003)/> However, the widespread use of pingers along [[coastline]]s effectively excludes cetaceans such as porpoises from prime [[habitat]] and resources.<ref name=Culik (2001)>Culik (2001)</ref><ref name=Culik (2001)>Culik et al (2001)</ref> Cetaceans which are extremely sensitive to noise are effectively being driven from their preferred coastal habitats by the use of acoustic devices. In poorer quality habitat, harbour porpoises are subjected to increased competition for resources. This situation is recognized as range contraction which can be a result of [[climate change]], [[anthropogenic]] activity, or [[Population dynamics of fisheries|population]] decline. Large scale range contractions are considered indicative of impending [[extinction]].<ref name=Boughton (2005)>Boughton et al (2005)</ref> A similar form of deterrent is noise pollution originating from vessel traffic. ====Fishing regulations and management==== Management and regulation are lacking in many [[fisheries]] today. [[Fisheries management|Management measures]] are urgently needed to monitor fisheries (and [[Illegal, unreported and unregulated fishing|illegal fisheries]]) to protect cetaceans. Efforts to document bycatch should focus on [[Gillnet|gill-net]] fisheries because cetaceans are more likely to be caught in gill-nets. Conservation efforts should be directed to areas where marine mammal bycatch is high but where no infrastructure exists to assess the impact.<ref name=Read (2006)/> There is a lack of reporting on a global scale of cetacean bycatch. In the U.S. the [[Marine Mammal Protection Act]] prohibits the use and sale of marine mammals captured by fisheries.<ref name=Read (2006)/> Similar legislation prohibits the use and sale of marine mammals in other countries. A marine mammal mortality monitoring program for commercial fisheries occurs in the U.S. where “Take Reduction Teams” observe the extent of bycatch and then formulate strategies to reduce bycatch and Take Reduction Plans are put into place.<ref name=Read (2006)/> ====Temporary closure==== Temporary closure of fisheries during the short period of the year when cetaceans are migrating through the area would decrease bycatch significantly.<ref>Murray et al(2000)</ref> ====Observers on boat==== [[Fisheries observer|Observers]] on boats should be present on [[fishing vessel]]s to spot cetaceans in the water so that they can be avoided. This should be mandatory so that responsible fishing can take place.<ref>Animal Freedom (2008)</ref> ====Other Ways of Mitigating Bycatch==== *Choose only fish that are caught using cetacean friendly fishing gear. *Buy food that has a “dolphin safe” label. *Read The [[sustainable seafood]] guide for information on seafood that is produced sustainably. *Volunteer locally. *Support volunteer organizations such as [[Greenpeace]]. *Raise awareness for cetacean bycatch. Fish caught in nets that are designed not to harm dolphins is marketed as "dolphin safe", though this label may not be truly indicative of the harm done to dolphins in that fishery. ==Notes== {{reflist|3}} ==References== <div class="references-small"> * 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) [http://www.animalfreedom.org/english/information/bycatch.html ''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 Mammology. 82: 641-651. * 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 Kgs. 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. *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. * WWF Species Programme (2004) [http://assets.panda.org/downloads/bycatchjuly12lowres2004.pdf ''Cetacean bycatch and the IWC''] </div> ==Further Reading== <div class="references-small"> * Baird, RW and Guenther, TJ (1995). ''Account of harbour porpoise (Phocoena phocoena) strandings and bycatches along the coast of British Columbia.'' Rep. Int. Whal. Commn. Special Issue. 16: 159-168. * Cox, TM, Read, AJ, Swanner, D, Urian, K and D Waples. 2004. Behavoural 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)</ref> 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. * 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. </div> ==External links== *[http://bycatch.env.duke.edu Project GLOBAL: Global Bycatch Assessment of Long-Lived Species project] *[http://www.eurocbc.org European Cetacean Bycatch Campaign] *[http://www.cetaceanbycatch.org/ Cetacean Bycatch Resource Center] *[http://www.anglers-net.co.uk/sacn/release07.htm Sea Anglers Conservation Network press release on cetacean bycatch] *[http://www.snopes.com/critters/crusader/whalethanks.asp Newspaper article describes an ensnared whale who seemingly thanked her rescuers] *[http://www.worldwildlife.org/news/displayPR.cfm?prID=203 Scientists rank endangered dolphins and porpoises most in need of immediate action] *[http://www.greenpeace.org.uk/media/reports/cetacean-bycatch-and-pelagic-trawling A WWF Press Release about bycatch] *[http://www.animalfreedom.org/english/information/bycatch.html A cetacean bycatch web page by Animal Freedom] *[http://www.ens-newswire.com/ens/jul2002/2002-07-24-06.asp New project will tackle whale entanglement, article by Environmental News Service] *[http://www.eartheasy.com/eat_sustainable_seafoods.htm Learn about sustainable seafood and the Sustainable Seafood Guide] {{Cetacea}} {{fisheries and fishing}} [[Category:Environmental issues with fishing]]