Marine mammal distribution in Ecuador: surveys aboard a ship of opportunity as a means of monitoring relative abundance
Keywords:distribution, ships of opportunity, visual survey
Five marine mammal surveys between 2008 and 2011 were conducted aboard the Buque de Investigación Orion (the research vessel for the Oceanographic Institute of the Ecuadorian Navy) within oceanic waters adjacent to mainland Ecuador and the Galápagos Islands. The surveys dedicated extensive time in deep, oﬀshore waters where cetaceans were not densely present. Sightings of 12 species were compared with an earlier survey aboard the B/I Orion in 2001 as well as with a subset of published data from three NOAA STAR (Stenella Abundance Research) surveys between 1999 and 2003. Additionally, a small boat, near-shore survey, was conducted during June 2010 among and
near the Galápagos Islands. Encounter rates ranged annually from 0.012 cetacean/km to 0.027 cetacean/km. The highest encounter rate aboard the B/I Orion took place during the April 2009 survey. In order to compare sighting
rates between the B/I Orion and NOAA platforms, the average eﬀective half-strip widths were used to determine encounter rates per area eﬀectively searched. A zonation within the study region was observed between odontocete and
balaenopterid cetaceans as well as between striped (Stenella coeruleoalba) and short-beaked common dolphins (Delphinus delphis). Several methodological aspects of surveys and geographical features that may inﬂuence encounter rates and subsequent abundance estimates are discussed. This study demonstrates that vessels of opportunity provide a valuable means of studying open-ocean and coastal distributions of marine mammals. Possible methodological improvements, such as the use of high-power binoculars, that could increase the absolute number of sightings, the efficiency of these opportunistic surveys, and improve the sighting rates of more evasive species are discussed.
Alava, J.J., Barragán, M.J., Castro, C. and Carvajal, R. (2005) A note on strandings and entanglements of humpback whales (Megaptera novaeangliae) in Ecuador. Journal of Cetacean Research and Management 7(2): 163-168.
Au, W.K. and Perryman, W.L. (1985) Dolphin habitats in the eastern tropical Pacific. Fishery Bulletin 83(4): 623-643.
Barlow, J. (2015) Inferring trackline detection probabilities, g(0), for cetaceans from apparent densities in diﬀerent survey conditions. Marine Mammal Science 31(3): 923-943. https://doi.org/10.1111/mms.12205
Buckland, S.T., Anderson, D.R., Burnham, K.P. and Laake, J.L. (1993) Distance sampling: Estimating abundance of biological populations. Chapman and Hall, London, UK.
Buckland, S., Anderson, D.R., Burnham, K.P., Laake, J., Borchers, D. and Tomas, L. (2001) Introduction to distance sampling: estimating abundance of biological populations. Oxford University Press, Oxford, UK. https://doi.org/10.1007/978-94-011-1572-8 https://doi.org/10.1007/978-94-011-1574-2
Chavez, F.P. and Barber, R.T. (1987) An estimate of new production in the equatorial Pacific. Deep Sea Research Part A. Oceanographic Research Papers 34(7): 1229-1243. https://doi.org/10.1016/0198-0149(87)90073-2
Clarke, R. (1962) Whale observation and whale marking oﬀ the coast of Chile in 1958 and from Ecuador towards and beyond the Galápagos Islands in 1959. Norsk Hvalfangsttid 51: 265-287.
Clarke, R., Fernando, F., Obla, P. and Patricia, B. (2001) Ballenas y delfines observados por la expedición Ballenas Libres durante el crucero oceanográfco CO-II-01 entre Guayaquil y las Islas Galápagos del 17 de Septiembre al 9 de Octubre 2001. Acta Oceanografica del Pacifco 11(1): 1-4.
Denkinger, J., Oña, J., Alarcón, D., Merlen, G., Salazar, S. and Palacios, D. (2013) From whaling to whale watching: Cetacean presence and species diversity in the Galápagos Marine Reserve. Science and Conservation in the Galápagos Islands 1: 217-235. https://doi.org/10.1007/978-1-4614-5794-7_13
Félix, F. (1997) Organization and social structure of the coastal bottlenose dolphin Tursiops truncatus in the Gulf of Guayaquil, Ecuador. Aquatic Mammals 23(1): 1-16.
Félix, F. and Haase, B. (2001) The humpback whale oﬀ the coast of Ecuador, population parameters and behavior. Revista de Biología Marina y Oceanografía 36(1): 61-74. https://doi.org/10.4067/S0718-19572001000100006
Félix, F. and Haase, B. (2005) Distribution of humpback whales along the coast of Ecuador and management implications. Journal of Cetacean Research and Management 7(1): 21-31.
Félix, F., Munoz, M., Falconi, J., Botero, N. and Haase B. (2011). Entanglement of humpback whales in artisanal fshing gear in Ecuador. Journal of Cetacean Research and Management Special Issue 3: 285-290.
Fiedler, P.C. and Reilly, S.B. (1994) Interannual variability of dolphin habitats in the eastern tropical Pacifc. II: Eﬀects on abundances estimated from tuna vessel sightings, 1975-1990. Fishery Bulletin 92: 451-463.
Lerczak, J.A. and Hobbs, R.C. (1998) Calculating sighting distances from angular readings during shipboard, aerial, and shore-based marine mammal surveys. Marine Mammal Science 14(3):590-599.
Loesh, H. (1966) Observación de ballenas en aguas ecuatorianas. Informe de datos, mayo de 1963 y enero-febrero de 1964. Boletín Científco y Técnico 4: 1-18.
Mullin, K. and Fulling, G. (2004) Abundance of cetaceans in the oceanic northern Gulf of Mexico, 1996-2004. Marine Mammal Science 20: 787-807. https://doi.org/10.1111/j.1748-7692.2004.tb01193.x
Palacios, D., Gerrodette, T., Herrera, J.C., García, C., Soler, G.A., Avila, I.C., Bessudo, S., Hernandez, E., Trujilo, F. and González, I.F. (2009) Cetacean distribution and relative abundance in Colombia’s Pacific EEZ from survey cruises and platforms of opportunity. Journal of Cetacean Research and Management 12(1): 45-60.
Santos, M.B., Pierce, G.J., Herman, J., Lopez, A., Guerra, A., Mente, E. and Clarke, M.R. (2001) Feeding ecology of Cuvier’s beaked whale (Ziphius cavirostris): a review with new information on the diet of this species. Journal of the Marine Biological Association of the UK 81(4): 687-694. https://doi.org/10.1017/S0025315401004386
Scheidat, M., Castro, C., Denkinger, J., González, J. and Adelung, D. (2000) A breeding area for humpback whales (Megaptera novaeangliae) oﬀ Ecuador. Journal of Cetacean Research and Management 2(3): 165-171.
Scott, M.D. and Chivers, S.J. (2009) Movements and diving behavior of pelagic spotted dolphins. Marine Mammal Science 25: 137-160. https://doi.org/10.1111/j.1748-7692.2008.00241.x
Smith, S.C. and Whitehead, H. (2000) The diet of Galapagos sperm whales (Physeter macrocephalus) as indicated by fecal sample analysis. Marine Mammal Science 16: 315-325. https://doi.org/10.1111/j.1748-7692.2000.tb00927.x
Taylor, B.L., Baird, R., Barlow, J., Dawson, S.M., Ford, J., Mead, J.G., Notarbartolo di Sciara, G., Wade, P. and Pitman, R.L. (2008). Physeter macrocephalus. The IUCN Red List of Treatened Species 2008: e.T41755A10554884. Downloaded on 12 January 2017.
Tomas, L., Buckland, S.T., Rexstad, E.A., Laake, J.L., Strindberg, S., Hedley, S.L., Bishop, J.R.B., Marques, T.A. and Burnham, K.P. (2010) Distance software: design and analysis of distance sampling surveys for estimating population size. Journal of Applied Ecology 47: 5-14. https://doi.org/10.1111/j.1365-2664.2009.01737.x
Townsend, C.H. (1935) The distribution of certain whales as shown by the logbook records of American whaleships. Zoologica 16: 133-144.
Whitehead, H. and Waters, S. (1992) Population structure of female and immature sperm whales (Physeter macrocephalus) oﬀ the Galapagos Islands. Canadian Journal of Fisheries and Aquatic Sciences 49: 78-84. https://doi.org/10.1139/f92-009
Whitehead, H., Christal, J. and Dufault, S. (1996) Past and distant whaling and the rapid decline of sperm whales oﬀ the Galápagos Islands. Conservation Biology 11(6): 1387-1396. https://doi.org/10.1046/j.1523-1739.1997.96246.x
Williams, R., Hedley, H.L. and Hammond, P.S. (2006) Modeling distribution and abundance of Antarctic baleen whales using ships of opportunity. Ecology and Society 11(1): 1-28. https://doi.org/10.5751/ES-01534-110101
LicenseAuthors who publish with this journal agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).