Social structure of Atlantic spotted dolphins (Stenella frontalis) off Bimini, The Bahamas (2003–2016): alternate reasons for preferential association in delphinids
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Social systems are characterized by the associations and interactions between individuals. For highly social groups such as delphinids, understanding the demographics and long-term association patterns of a population is the first step in interpreting its overall social structure and specific relationships between individuals. This study investigated the social patterns of a population of Atlantic spotted dolphins (Stenella frontalis) off Bimini, The Bahamas, during a 14-year period (2003–2016). We generated association indices and conducted cluster, network, and temporal analyses using SOCPROG 2.8. Dolphins in this population display long-term, year-round residency around Bimini, as well as long-term preferences in association with a combination of rapid disassociation, constant companions, and casual acquaintances. We found no evidence of distinct social clusters within the study group; however, we discovered at least one subgroup with higher association than the rest of the population. This group was composed of male spotted dolphins, which overall tended to associate together more than females and chose companions with similar levels of association to themselves. Despite strong relationships between males, we found no evidence for the existence of alliances or coalitions. This study provides a baseline understanding of the social structure of this population that will allow us to investigate the variable relationships between individuals, in addition to exploring the effects of demographic changes within the resident population.
KeywordsAssociation Atlantic spotted dolphin Stenella frontalis Bahamas Social structure SOCPROG
We thank the Dolphin Communication Project (DCP) for support with data collection and dolphin identifications, which were completed over the years with assistance from K. DeStefano, D. Blanding, and seasonal interns from 2003 to 2016. This study was carried out as part of the lead author’s doctoral dissertation in the Graduate Program in Integrative Biology at the University of Massachusetts Dartmouth. This paper was greatly improved by the comments of two anonymous reviewers.
Major funding and support for data collection from 2003 to 2016 were provided by DCP, Mystic Aquarium & Institute for Exploration, Bill & Nowdla Keefe’s Bimini Undersea, the At-Sea Processors’ Association Pollock Conservation Cooperative Fund at Alaska Pacific University, the Department of Biology at the University of Massachusetts Dartmouth, and Al Sweeting, Jr. The manuscript represents contribution #120 from DCP.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
All applicable international, national, and/or institutional guidelines for the care and use of animals were followed. Permits to conduct scientific study on the dolphins around Bimini were obtained annually by DCP from the Department of Fisheries (Marine Resources), Ministry of Agriculture, Fisheries and Local Government, Nassau, The Bahamas. This article does not contain any studies with human participants performed by any of the authors.
- Borgatti SP, Everett MG, Freeman LC (2002) Ucinet 6 for Windows: Software for Social Network Analysis. Analytic Technologies, HarvardGoogle Scholar
- Connor RC, Wells RS, Mann J, Read AJ (2000) The bottlenose dolphin: social relationships in a fission-fusion society. In: Mann J, Connor RC, Tyack PL, Whitehead H (eds) Cetacean societies: field studies of whales and dolphins. The University of Chicago Press, Chicago, pp 91–126Google Scholar
- Dudzinski KM (1996) Communication and behavior in the Atlantic spotted dolphin (Stenella frontalis): relationships between vocal and behavioral activities. Dissertation, Texas A&M UniversityGoogle Scholar
- Dudzinski K (1998) Contact behavior and signal exchange in Atlantic spotted dolphins (Stenella frontalis). Aquat Mamm 24:129–142Google Scholar
- Dudzinski KM, Clark CW, Würsig B (1995) A mobile video-acoustic array for simultaneously recording dolphin behavior and vocalizations underwater. Aquat Mamm 21:187–193Google Scholar
- Elliser CR, Herzing DL (2012) Community structure and cluster definition of Atlantic spotted dolphins, Stenella frontalis, in the Bahamas. Mar Mamm Sci 00:1–17Google Scholar
- Fennessy JT (2004) Ecology of desert-dwelling giraffe Giraffa Camelopardalis angolensis in northwestern Namibia. Dissertation, University of SydneyGoogle Scholar
- Melillo-Sweeting K, Turnbull SD, Guttridge TL (2014) Evidence of shark attacks on Atlantic spotted dolphins (Stenella frontalis) off Bimini, The Bahamas. Mar Mamm Sci:1-7Google Scholar
- Moss C (1976) Portraits in the wild. Animal behaviour in East Africa. Hamish Hamilton Ltd., LondonGoogle Scholar
- Norris KS, Würsig B, Wells RS, Würsig M (1994) The Hawaiian spinner dolphin. University of California Press, BerkeleyGoogle Scholar
- Perrin WF (1970) Color pattern of the eastern Pacific spotted porpoise Stenella graffmani Lönnberg (Cetacean, Delphinidae). Zoologica 54:135–149Google Scholar
- Würsig B, Wells RS, Norris KS, Würsig M (1994) A spinner dolphin day. In: Norris KS, Würsig B, Wells RS, Würsig M, Brownlee SM, Johnson CM, Solow J (eds) The Hawaiian spinner dolphin. University of California Press, Berkeley, pp 65–102Google Scholar