Pantropical spotted dolphins in Hawai‘i

Pantropical spotted dolphins (Stenella attenuata) high speed swimming off the island of Hawai‘i. Pantropical spotted dolphins are the second-most frequently encountered species in our study – between 2000 and late 2021 we’ve had over 600 encounters with this species! Like false killer whales, pantropical spotted dolphins are found both in shallow waters (<100 m) and in deep offshore waters (over 4,000 m). We have just recently started a photo-catalog for this species, and have over 100 distinctive animals so far, with matches across multiple years suggesting that this species displays site fidelity. This finding aligns well with previous work that has shown genetic differentiation of pantropical spotted dolphins between the island areas of O‘ahu, Maui Nui, and Hawai‘i Island. 

 

Pantropical spotted dolphin mother and calf. Group sizes we’ve encountered for this species have ranged from lone individuals to an estimated 350 individuals – the mean group size is 65.

 

Juvenile pantropical spotted dolphin leaping, presumably to try to dislodge a remora.

 

Juvenile pantropical spotted dolphin leaping, this one with two remoras. We’ve found that pantropical spotted dolphins are the species that remoras attach most frequently to in the main Hawaiian Islands – out of 153 encounters where we noted a remora was present, 94 of those encounters (61%) were with pantropical spotted dolphins! 

 

Although we find pantropical spotted dolphins close to shore (particularly in the 4-island region), off the island of Hawai‘i they are most frequently seen in waters deeper than 1,000 m and groups can be found in very deep water far offshore. This graph shows the sighting rates per 100 hours of search effort by depth.

 

Pantropical spotted dolphin. This species often bowrides – this photo was taken of an individual bowriding on our research vessel.

 

With pantropical spotted dolphins we try to collect genetic samples from most groups for studies of population structure – this work was part of a Ph.D. thesis by Sarah Courbis at Portland State University. Her work has shown evidence that there are multiple populations of spotted dolphins within the main Hawaiian Islands, as has been demonstrated for spinner dolphins and common bottlenose dolphins. A copy of her thesis and a publication from this research can be downloaded below.

A pantropical spotted dolphin with a wound from a vessel propeller. 

 

Small fishing vessels in Hawai‘i regularly “fish” spotted dolphins, repeatedly trolling through groups to try to catch associated tuna. We recently published this paper demonstrating that fishing vessels frequently use this tactic, increasing the risk of dolphins becoming hooked.

 

A pantropical spotted dolphin with line injuries on the dorsal fin, most likely caused by interactions with fishing gear.

 

Pantropical spotted dolphin porpoising.

 

For more information on pantropical spotted dolphins see the following:

  • Apprill, A., C.A. Miller, A.M. Van Cise, J.M. U’Ren, M.S. Leslie, L. Weber, R.W. Baird, J. Robbins, S. Landry, A. Bogomolni, and G. Waring. 2020. Marine Mammal Skin Microbiotas Are Influenced by Host Phylogeny. Royal Society Open Science 7:192046. doi: 10.1098/rsos.192046. Download PDF copy. 
  • Baird, R.W., and D.L. Webster. 2020. Using Dolphins to Catch Tuna: Assessment of Associations Between Pantropical Spotted Dolphins and Yellowfin Tuna Hook and Line Fisheries in Hawaii. Fisheries Research 230(October 2020), 105652. doi: 10.1016/j.fishres.2020.105652. Download PDF copy
  • Howe, M., M.O. Lammers, and R.W. Baird. 2019. Participatory Science and Directed Survey Methods: A Case Study with Odontocetes in the Maui Nui Region of the Hawaiian Islands. Journal of Cetacean Research Management 20:101-109. Download PDF copy. 
  • Howe, M., M.O. Lammers, and R.W. Baird. 2019. Participatory Science and Directed Survey Methods: A Case Study with Odontocetes in the Maui Nui Region of the Hawaiian Islands. Poster presented at the World Marine Mammal Conference, Barcelona, Spain, December 7-12, 2019. Download PDF copy. 
  • Baird, R.W., D.L. Webster, S.M. Jarvis, E.E. Henderson, S.L. Watwood, S.D. Mahaffy, B.D. Guenther, J.K. Lerma, C.J. Cornforth, A.W. Vanderzee and D.B. Anderson. 2019. Odontocete studies on the Pacific Missile Range Facililty in August 2018: satellite-tagging, photo-identification, and passive acoustic monitoring. Prepared for Commander, Pacific Fleet, under Contract No. N62470-15-D-8006 Task Order 6274218F0107 issued to HDR Inc., Honolulu, HI. Download PDF copy
  • Baird, R.W. and D.L. Webster. 2019. Movements of satellite-tagged pantropical spotted dolphins in relation to stock boundaries in Hawaiian waters. Document PSRG-2019-15 submitted to the Pacific Scientific Review Group, March 5-7, 2019, Olympia, WA. Download PDF copy
  • Baird, R.W., and D.L. Webster, 2019. Using dolphins to catch tuna: assessment of interactions between pantropical spotted dolphins and hook and line fisheries in Hawai’i. Document PSRG-2019-16 presented to the Pacific Scientific Review Group, March 5-7, 2019, Olympia, WA. Download PDF copy
  • Baird, R.W., D.L. Webster, S.M. Jarvis, K.A. Wood, C.J. Cornforth, S.D. Mahaffy, K.K. Martien, K.M. Robertson, D.B. Anderson and D.J. Moretti. 2018. Odontocete studies on the Pacific Missile Range Facility in August 2017: satellite-tagging, photo-identification, and passive acoustic monitoring. Prepared for Commander, Pacific Fleet, Pearl Harbor, HI. Download PDF copy
  • Baird, R.W., D.L. Webster, R. Morrisey, B.K. Rone, S.D. Mahaffy, A.M. Gorgone, D.B. Anderson, E.E. Henderson, S.W. Martin and D.J. Moretti. 2017. Odontocete studies on the Pacific Missile Range Facility in February 2016: satellite-tagging, photo-identification, and passive acoustic monitoring. Prepared for Commander, Pacific Fleet, Pearl Harbor, HI. Download PDF copy
  • Silva, T.L., T.A. Mooney, L.S., Sayigh, P.L. Tyack, R.W. Baird and J.N. Oswald. 2016. Whistle characteristics and daytime dive behavior in pantropical spotted dolphins (Stenella attenuata) in Hawai’i measured using digital acoustic recording tags (DTAGs). Journal of the Acoustical Society of America 140: in press. Download PDF copy
  • Silva, T.L., T.A. Mooney, L.S. Sayigh, P.L. Tyack, R.W. Baird, and J.N. Oswald. 2016. Successful suction-cup tagging of a small delphinid species, Stenella attenuata: Insights into whistle characteristics. Marine Mammal Science DOI: 10.1111/mms.12376 Download PDF copy
  • Apprill, A., C.A. Miller, R.W. Baird, J. Robbins, M.E. Niemeyer, G.T. Waring, A. Bogomolni, S. Landry. 2015. Comparison of skin microbiomes across 16 marine mammal species. Abstract (Proceedings) 21st Biennial Conference on the Biology of Marine Mammals, San Francisco, California, December 14-18, 2015. View abstract
  • Baird, R.W. and D.L. Webster. 2015. Unintended consequences of using dolphins to catch tuna: examining the extent and nature of hook and line fishery interactions with pantropical spotted dolphins off the island of Hawai’i. Abstract (Proceedings) 21st Biennial Conference on the Biology of Marine Mammals, San Francisco, California, December 14-18, 2015. View abstract
  • Baird, R.W., D. Cholewiak, D.L. Webster, G.S. Schorr, S.D. Mahaffy, C. Curtice, J. Harrison and S.M. Van Parijs. 2015. Biologically important areas for cetaceans within U.S. waters – Hawai’i regionAquatic Mammals 41:54-64 Download PDF copy
  • Silva, T.L. T.A. Mooney, L.S. Sayigh, P.L. Tyack and R.W. Baird. 2015. Whistle characteristics and daytime dive behavior of pantropical spotted dolphins (Stenella attenuata) in Hawai’i. Abstract (Proceedings) 21st Biennial Conferene on the Biology of Marine Mammals, San Francisco, California, December 14-18, 2015. View abstract
  • Foltz, K., R.W. Baird, G.M. Ylitalo and B.A. Jensen. 2014. Cytochrome P4501A1 expression in blubber biopsies of endangered false killer whales (Pseudorca crassidens) and nine other odontocete species from Hawai’i. Ecotoxicology DOI: 10.1007/s10646-014-1300-0 Download PDF copy
  • Courbis, S., R.W. Baird, F. Cipriano and D. Duffield. 2014. Multiple populations of pantropical spotted dolphins in Hawaiian waters. Journal of Heredity 105:627-641. Download PDF copy
  • Baird, R.W., D.L. Webster, S.D. Mahaffy, G.S. Schorr, J.M. Aschettino and A.M. Gorgone. 2013. Movements and spatial use of odontocetes in the western main Hawaiian Islands: results of a three-year study off O’ahu and Kaua’i. Final report under Grant No. N00244-10-1-0048 from the Naval Postgraduate School. Download PDF copy
  • Baird, R.W., D.L. Webster, J.M. Aschettino, G.S. Schorr and D.J. McSweeney. 2013. Odontocete cetaceans around the main Hawaiian Islands: habitat use and relative abundance from small-boat sighting surveys. Aquatic Mammals 39:253-269. Download PDF copy
  • Burgess, W.C., E.M. Oleson and R.W. Baird. 2011. A hydrodynamic acoustic recording tag for small cetaceans and first results from a pantropical spotted dolphins. Poster presented at the 19th Biennial Conference on the Biology of Marine Mammals, Tampa, Florida, November-December 2011. Download PDF copy
  • Courbis, S.S. 2011. Population structure of island-associated pantropical spotted dolphins (Stenella attenuata) in Hawaiian waters. Ph.D. Dissertation, Portland State University. Download PDF copy
  • Courbis, S., R.W. Baird, F. Cipriano and D. Duffield. 2009. Population structure of pantropical spotted dolphins near the main Hawaiian Islands: evidence of multiple genetic stocks. Poster presented at the 18th Biennial Conference on the Biology of Marine Mammals, Quebec, October 2009. Download PDF copy
  • Baird, R.W. 2006. Hawai’i’s other cetaceans. Whale and Dolphin Magazine 11:28-31 Download PDF copy
  • Baird, R.W., D.J. McSweeney, D.L. Webster, A.M. Gorgone and A.D. Ligon. 2003. Studies of odontocete population structure in Hawaiian waters: results of a survey through the main Hawaiian Islands in May and June 2003. Report prepared under Contract No. AB133F-02-CN-0106 from the National Oceanic and Atmospheric Administration, Western Administrative Support Center, 7600 Sand Point Way N.E., Seattle, WA 98115 USA PDF available at ResearchGate
  • Baird, R.W., A.D. Ligon, S.K. Hooker, and A.M. Gorgone. 2001. Sub-surface and night-time behaviour of pantropical spotted dolphins in Hawaii. Canadian Journal of Zoology 79: 988-996. Download PDF copy

All photos are copyrighted and should not be used without permission.

Updated November 2021.

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