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). Bycatch mortality of the species dates back to at least 1962 (Clarke 1962), and has escalated within the past thirty years as gillnet use has increased (Dawson 2009; Reyes & Oporto 1994). From 1988 to1990, 32 to 63 individuals were accidentally entangled annually at Queule, a fishing port on the Chilean coast (Reyes & Oporto 1994).
Chilean dolphins are accidentally entangled in anti-predator nets erected by fishermen around fish and shellfish farms to deter sea lions, or are deliberately killed by these same fishermen (Claude et al 2000; Kemper et al 2003). They have also been reported as entangled in intertidal nets designed to catch salmon that have escaped from aquaculture facilities (Dawson 2009).
Very little is known about population dynamics and abundance of the Chilean dolphin (Ribeiro et al 2007), but it is believed that the species exists in small, local subpopulations that exhibit marked site fidelity. Consequently, deaths due to bycatch can have potentially severe impacts on overall population health and structure (Dawson 2009). One possible mitigation method to this bycatch issue is the use of acoustic pingers; however, no trials have been carried out for this species.
Clarke, R. 1962. Whale observation and whale marking off the coast of Chile in 1958 and from Ecuador towards and beyond the Galapagos Islands in 1959. Norsk Hvalfangsttid 51(7): 285-287.
Claude, M, JA Oporto, L Brieva, PC Espinosa & WM Arqueros. 2000. La ineficiencia de la salmonicultura en Chile: aspectos, sociales, economicos y ambientales. Terram Publicaciones, Santiago, Chile. PDF available http://www.terram.cl/nuevo/images/stories rppublicos1/pdf.
Dawson, SM. 2009. Cephalorhynchus dolphins. In: WF Perrin, B Wursig, JGM Thewissen (eds), Encyclopedia of Marine Mammals, 2nd ed. pp. 191-196. Academic Press, Amsterdam.
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Reeves, RR, EA Crespo, S Dans, TA Jefferson, L Karczmarski, K Laidre, G O'Corry-Crowe, S Pedraza, L Rojas-Bracho, ER Secchi, E Slooten, BD Smith, JY Wang & K Zhou. 2008. Cephalorhynchus eutropia. In: IUCN Red List of Threatened Species. Version 2012.1. Accessed 10 October 2012. www.iucnredlist.org
Reyes, JC & JA Oporto. 1994. Gillnet fisheries and cetaceans in the southeast Pacific. Report of the International Whaling Commission (Special Issue 15) SC/090/G11.
Ribeiro, S, FA Viddi, JL Cordeiro & TRO Freitas. 2007. Fine-scale habitat selection of Chilean dolphins (Cephalorhynchus eutropia): interactions with aquaculture activities in southern Chiloe Island, Chile. Journal of the Marine Biological Associated of the United Kingdom 87(1): 119-128.
Torres, D, J Yanez & P Cattan. 1979. Mamiferos marinos de Chile: antecedentes y situacion actual. Biol Pesq (Chile) 11: 49-81.