Hostname: page-component-586b7cd67f-rcrh6 Total loading time: 0 Render date: 2024-11-30T23:56:19.394Z Has data issue: false hasContentIssue false
  • English
  • Français

Prevalence of scars of anthropogenic origin in coastal bottlenose dolphin in Ecuador

Published online by Cambridge University Press:  09 May 2017

Fernando Félix ,
Ruby Centeno ,
Juan Romero ,
Melanie Zavala  and
Óscar Vásconez
Fernando Félix*
Affiliation:
Museo de Ballenas, Av. Enríquez Gallo entre calles 47 and 50. Salinas, Ecuador Pontificia Universidad Católica del Ecuador (PUCE), Av. 12 de Octubre 1076, Quito, Ecuador
Ruby Centeno
Affiliation:
Time for English and Spanish School, Av. Circunvalación 906, Guayaquil, Ecuador
Juan Romero
Affiliation:
Refugio de Vida Silvestre Manglares el Morro, Recinto Puerto El Morro, Barrio Cruz del Puerto, Guayaquil, Ecuador
Melanie Zavala
Affiliation:
Universidad de Guayaquil, Facultad de Ciencias Naturales, Escuela de Biología, Guayaquil, Ecuador
Óscar Vásconez
Affiliation:
Refugio de Vida Silvestre Manglares el Morro, Recinto Puerto El Morro, Barrio Cruz del Puerto, Guayaquil, Ecuador
*
Correspondence should be addressed to: F. Félix, Museo de Ballenas, Av. Enríquez Gallo entre calles 47 and 50. Salinas, Ecuador and Pontificia Universidad Católica del Ecuador (PUCE), Av. 12 de Octubre 1076, Quito, Ecuador email: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

The prevalence of scars and wounds of anthropogenic origin was assessed in seven different coastal bottlenose dolphin communities (Tursiops truncatus) on the south-western coast of Ecuador. Between 2011 and 2017 a total of 117 trips were conducted representing a total sampled distance of 6281 km. Twenty-five of the 189 (13.2%) free-ranging photo-identified dolphins were recorded with dorsal fin damage, V-shaped wounds, sawed edges and deformities in the caudal region. The scarring prevalence ranged from 0 to 44.4% and was associated with either fishing interactions or vessel strikes. Dolphin scarring increased five times in the last 25 years from 2.2 to 11.1% and was correlated with a decrease in population in the inner estuary of the Gulf of Guayaquil. Damaged dorsal fins are associated mainly with fishing gear. V-shaped wounds were recorded in three different communities, Posorja, Estero Salado and Salinas, and given their severity associated with either fishing gear or vessel strikes. During the study period three dolphins were found entangled in fishing gears, two in gillnets and one in a long-line, emphasizing the threats posed by current fishing practice to the species. More effective management measures are urgently needed to reverse the observed population decline. This may include reduction of fishing effort, implementation of area-based approaches to coastal planning (including Marine Protected Area designations) and support for further research to understand the problem. Given the difficulty in taking direct observations, scarring prevalence is proposed as a proxy for estimating boat traffic and fishing gear impacts upon cetaceans.

Keywords

vessel strikesfishing interactionTursiops truncatusconservationbottlenose dolphinscarringEcuador
Type
Research Article
Information
Journal of the Marine Biological Association of the United Kingdom , Volume 98 , Special Issue 5: Marine Mammals , August 2018 , pp. 1177 - 1186
Copyright
Copyright © Marine Biological Association of the United Kingdom 2017 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Azevedo, A.F., Lailson-Brito, J., Dorneles, P.R., van Sluys, M., Cunha, H.A. and Fragoso, A.B.L. (2009) Human-induced injuries to marine tucuxis (Sotalia guianensis) (Cetacea: Delphinidae) in Brazil. Marine Biodiversity Records 2. doi: 10.1017/S1755267208000262.Google Scholar
Baird, R.W. and Gorgone, A.M. (2005) False killer whale dorsal fin disfigurements as a possible indicator of long-line fishery interactions in Hawaiian waters. Pacific Science 59, 593–601.Google Scholar
Bechdel, S.E., Mazzoil, M.S., Murdoch, M.E., Howells, E.M., Reif, J.S., McCulloch, S.D., Schaefer, A.M. and Bossart, G.D. (2009) Prevalence and impacts of motorized vessels on bottlenose dolphins (Tursiops truncatus) in the Indian River Lagoon, Florida. Aquatic Mammals 35, 367–377. doi: 10.1578/AM.35.3.2009.367.Google Scholar
Bloom, P. and Jager, M. (1994) The injury and subsequent healing of a serious propeller strike to a wild bottlenose dolphin (Tursiops truncatus) resident in cold waters off the Northumberland coast of England. Aquatic Mammals 20, 59–64.Google Scholar
Bossley, M.I. and Woolfall, M.A. (2014) Recovery from severe cutaneous injury in two free ranging bottlenose dolphins (Tursiops spp.). Journal of Marine Animals and their Ecology 7, 12–16.Google Scholar
Byard, R.W., Winskog, C., Machado, A. and Boardman, W. (2012) The assessment of lethal propeller strike injuries in sea mammals. Journal of Forensic and Legal Medicine 19, 158–161. doi: 10.1016/j.jflm.2011.12.017.Google Scholar
Corkeron, P.J., Morris, R.J. and Bryden, M.M. (1987) A note on healing of large wounds in bottlenose dolphins, Tursiops truncatus. Aquatic Mammals 13, 96–98.Google Scholar
Dwyer, S.L., Kozmian-Ledward, L. and Stockin, K.A. (2014) Short-term survival of severe propeller strike injuries and observations on wound progression in a bottlenose dolphin. New Zealand Journal of Marine and Freshwater Research. doi: 10.1080/00288330.2013.866578.Google Scholar
Elwen, S.H. and Leeney, R.H. (2010) Injury and subsequent healing of a propeller strike injury to a Heaviside's dolphin (Cephalorhynchus heavisidii). Aquatic Mammals 36, 382–387. doi: 10.1578/AM.36.4.2010.382.Google Scholar
Félix, F. (1994) Ecology of the coastal bottlenose dolphin Tursiops truncatus in the Gulf of Guayaquil, Ecuador. Investigations on Cetacea 25, 235–256.Google Scholar
Félix, F. (1997) Organization and social structure of the bottlenose dolphin Tursiops truncatus in the Gulf of Guayaquil, Ecuador. Aquatic Mammals 23, 1–16.Google Scholar
Félix, F., Calderón, A., Vintimilla, M. and Bayas-Rea, R.A. (2017) Decreasing population trend in coastal bottlenose dolphin (Tursiops truncatus) communities from the Gulf of Guayaquil, Ecuador. Aquatic Conservation: Marine and Freshwater Ecosystems. doi: 10.1002/aqc.2763.Google Scholar
Félix, F., Haase, B., Denkinger, J. and Falconí, J. (2011) Varamientos de mamíferos marinos registrados en la costa continental de Ecuador entre 1996 y 2009. Acta oceanográfica del Pacífico 16, 61–73.Google Scholar
Fertl, D. (1994 a) Occurrence patterns and behavior of bottlenose dolphin (Tursiops truncatus) in the Galveston Ship Channel, Texas. Texas Journal of Science 46, 299–317.Google Scholar
Fertl, D. (1994 b) Occurrence, movements, and behavior of bottlenose dolphins (Tursiops truncatus) in association with the shrimp fishery in Galveston Bay, Texas. MSc Thesis. Texas A&M University, College Station, TX.Google Scholar
Freitas Nery, M., Espécie, M.A. and Marino Simão, S. (2008) Marine tucuxi dolphin (Sotalia guianensis) injuries as a possible indicator of fisheries interaction in southeastern Brazil. Brazilian Journal of Oceanography 56, 313–316, online version. doi: 10.1590/S1679–87592008000400007.Google Scholar
Halpern, B.S., Walbridge, S., Selkoe, K.A., Kappel, C.V., Micheli, F., D'Agrosa, C., Bruno, J.F., Casey, K.S., Ebert, C., Fox, H.E., Fujita, R., Heinemann, D., Lenihan, H.S., Madin, E.M.P., Perry, M.T., Selig, E., Spalding, M., Steneck, R. and Watson, R. (2012) A global map of human impact on marine ecosystems. Science 319, 948–952. doi: 10.1126/science.1151084.Google Scholar
Herrera, M., Castro, R., Coello, D., Saa, I. and Elías, E. (2013) Ports, coves and artisanal fishing settlements on mainland Ecuador. Instituto Nacional de Pesca, Ecuador. Boletín Especial 4, 616 pp. (Vols 1 and 2).Google Scholar
Irvine, L.M., Mate, B.R., Winsor, M.H., Palacios, D.M., Bograd, S.J., Costa, D.P. and Bailey, H. (2014) Spatial and temporal occurrence of blue whales off the U.S. West Coast, with implications for management. PLoS ONE 9, e102959. doi: 10.1371/journal.pone.0102959.Google Scholar
Jaramillo-Legorreta, A, Rojas-Bracho, L, Brownell, R.L. Jr, Read, A.J., Reeves, R.R., Ralls, K. and Taylor, B.L. (2007) Saving the vaquita: immediate action, not more data. Conservation Biology 21, 1653–1655.Google Scholar
Jiménez, P. and Alava, J. (2014) Population ecology and anthropogenic stressors of the coastal bottlenose dolphin (Tursiops truncatus) in the El Morro Mangrove and Wildlife Refuge, Guayaquil Gulf, Ecuador: towards conservation and management actions. In Samuels, J. (ed.) Dolphins: ecology, behavior and conservation strategies. Hauppauge, NY: Nova Science Publisher, pp. 129–163.Google Scholar
Knowlton, A.R. and Kraus, S.D. (2001) Mortality and serious injury of northern right whales (Eubalaena glacialis) in the Western North Atlantic Ocean. Journal of Cetacean Research and Management Special Issue 2, 193–208.Google Scholar
Kiszka, J., Pelourdeau, D. and Ridoux, V. (2008) Body scars and dorsal fin disfigurements as indicators of interaction between small cetaceans and fisheries around the Mozambique channel island of Mayotte. Western Indian Ocean Journal of Marine Science 7, 185–193.Google Scholar
Laist, D.W., Knowlton, A.R., Mead, J.G., Collet, A.S. and Podesta, M. (2001) Collisions between ships and whales. Marine Mammal Science 17, 35–75. doi: 10.1111/j.1748-7692.2001.tb00980.x.Google Scholar
Lewison, R., Crowder, L.B., Wallace, B.P., Moore, J.E., Cox, T., Zydelis, R., MacDonald, S., DiMatteo, A., Dunn, D.C., Kot, C.Y., Bjorkland, R., Kelez, S., Soykan, C., Steward, K.R., Sims, M., Boustany, A., Read, A.J., Halpin, P., Nichols, W.J. and Safina, C. (2014) Global patterns of marine mammal, seabird and sea turtle bycatch reveal taxa-specific and cumulative megafauna hotspots. Proceedings of the National Academy of Sciences USA 111, 5271–5276. doi: 10.1073/pnas.1318960111.Google Scholar
Luksenburg, J.A. (2014) Prevalence of external injuries in small cetaceans in Aruban waters, Southern Caribbean. PLoS ONE 9, e88988. doi: 10.1371/journal.pone.0088988.Google Scholar
Mann, J., Scott, R.A. and Smuts, B.B. (1995) Responses to calf entanglement in free-ranging bottlenose dolphins. Marine Mammal Science 11, 100–106.Google Scholar
Orams, M.B. and Deakin, R.B. (1997) Report on the healing of a large wound in a bottlenose dolphins Tursiops truncatus. In Hindell, M. and Kemper, C. (eds) Marine mammal research in the southern hemisphere, Volume 1. Status, ecology and medicine. Chipping Norton: Beatty & Sons, pp. 170–173.Google Scholar
Parsons, E.C.M. and Jefferson, T.A. (2000) Post-mortem investigations on stranded dolphins and porpoises from Hong Kong waters. Journal of Wildlife Diseases 36, 342–356. doi: http://dx.doi.org/10.7589/0090-3558-36.2.342.Google Scholar
Read, A.J., Drinker, P. and Northridge, S. (2006) Bycatch of marine mammals in U.S. and global fisheries. Conservation Biology 20, 163–169.Google Scholar
Reeves, R., Smith, B.D., Crespo, E. and di Sciara, N. (compilers). (2003) Whales, dolphins and porpoise: 2002–2010 conservation action plan for the world's cetaceans. Gland and Cambridge: IUCN/ Cetacean Specialist Group, ix +139pp.Google Scholar
Reeves, R.R., McClellan, K. and Werner, T.B. (2013) Marine mammal bycatch in gillnet and other entangling net fisheries, 1990 to 2011. Endangered Species Research 20, 71–97. doi: 10.3354/esr00481.Google Scholar
Stevenson, M. (1981) Seasonal variations in the Gulf of Guayaquil, a tropical estuary. Instituto Nacional de Pesca de Ecuador. Boletín Científico y Técnico 4, 1–131.Google Scholar
Steward, K.R., Lewison, R.L., Dunn, D.C., Bjorkland, R.H., Kelez, S., Halpin, P.N. and Crowder, L.B. (2010) Characterizing fishing efforts and spatial extent of coastal fisheries. PLoS ONE 5, e14451. doi: 10.1371/journal.pone.0014451.Google Scholar
Turvey, S.T., Pitman, R.L., Taylor, B.L., Barlow, J., Akamatsu, T., Barrett, L.A., Zhao, X., Reeves, R.R., Stewart, B.S., Wang, K., Wei, Z., Zhang, X., Pusser, L.T., Richlen, M., Brandon, J.R. and Wand, D. (2007) First human-caused extinction of a cetacean species? Biology Letters 3, 537–540. doi: 10.1098/rsbl.2007.0292.Google Scholar
Van Waerebeek, K., Baker, A.N., Félix, F., Gedamke, J., Iñiguez, M., Sanino, G.P., Secchi, E., Sutaria, D., Van Helden, A. and Wang, Y. (2007) Vessel collisions with small cetaceans worldwide and with large whales in the southern hemisphere, and initial assessment. Latin American Journal of Aquatic Mammals 6, 43–69.Google Scholar
Wells, R.S. and Scott, M.D. (1997) Seasonal incidence of boat strikes on bottlenose dolphins near Sarasota, Florida. Marine Mammal Science 13, 475–480.Google Scholar
Wells, R.S., Scott, M.D. and Irvine, A.B. (1987) The social structure of free-ranging bottlenose dolphins. In Genoways, H.H. (ed.) Current mammalogy, Volume I. New York, NY: Plenum Press, pp. 247–305.Google Scholar
Wells, S.R., Hofmann, S. and Moors, T. (1989) Entanglement and mortality of bottlenose dolphins, Tursiops truncatus, in recreational fishing gear in Florida. Fishery Bulletin 96, 647–650.Google Scholar
Visser, I.N. (1999) Propeller scars on and known home range of two orcas (Orcinus orca) in New Zealand waters. New Zealand Journal of Marine and Freshwater Research 33, 635–642. doi: 10.1080/00288330.1999.9516906.Google Scholar
Würsig, B. and Würsig, M. (1977) The photographic determination of group size, composition, and stability of coastal porpoises (Tursiops truncatus). Science 198, 755–756.Google Scholar
Zasloff, M. (2011) Observations on the remarkable (and mysterious) wound-healing process of the bottlenose dolphin. Journal of Investigative Dermatology 131, 2503–2505. doi: 10.1038/jid.2011.220. PMID 21776005.Google Scholar
Zavala, M. (2017) Área de ocupación y estructura social del bufeo costero Tursiops truncatus (Montagu, 1821) (Cetacea: Delphinidae) en la Puntilla de Santa Elena (Ecuador) desde noviembre 2015 hasta julio 2016. Bachelor thesis. Universidad de Guayaquil. 90 pp.Google Scholar