Long-term social structure of long-finned pilot whales (Globicephala melas) in the Strait of Gibraltar
Tóm tắt
The Strait of Gibraltar is inhabited by around 216 pilot whales, which are present all year round, and nothing is known about their social structure. The aim of this study is to analyse the inter-individual association patterns within this pilot whales community to (1) provide an insight on their long-term social system and (2) to assess the relationship between sexes within this social system. Between 1999 and 2006, 23,004 km was sampled in the Strait of Gibraltar, and 4,887 images of dorsal fins of pilot whales were taken from 226 groups. The sex of 56 of the individuals could be determined genetically. The strength of the behavioural relationships between dyads of individuals was calculated, and the temporal aspects of the social structure were evaluated, showing in a non-random social structure made by constant companions. The preferred associations between individuals consisted in associations of males–females. Eight long-term units could be found with different degrees of association rates. Consequently, we propose that, in the Strait, the pilot whales exhibit a hierarchical social system composed of a population encompassing several clans of pilot whales each containing several pods. Pods will then be formed by several line units, similar to killer whale matrilineal units.
Tài liệu tham khảo
Aguilar A, Jover L, Borrell A (1993) Heterogeneities in organochlorine profiles of Faroese long-finned pilot whales: indication of segregation between pods? Rep Int Whal Comm Spec Issue 14:359–367
Akaike H (1974) A new look at the statistical model identification. IEEE Trans Autom Control 19:716–723
Amos B, Hoelzel AR (1991) Long-term preservation of whale skin for DNA analysis. Genetic ecology of whales and dolphins. Rep Int Whal Comm Spec Issue 13:99–103
Amos B, Barrett J, Dover GA (1991a) Breeding behaviour of pilot whales revealed by DNA fingerprinting. Heredity 67:49–55
Amos B, Barrett J, Dover GA (1991b) Breeding system and social structure in the Faroese pilot whale as revealed by DNA fingerprinting. Rep Int Whal Comm Spec Issue 13:255–268
Amos B, Bloch D, Desportes G, Majerus TMO, Bancroft DR, Barrett JA, Dover GA (1993a) A review of the molecular evidence relating to social organisation and breeding system in the long-finned pilot whale. Rep Int Whal Comm Spec Issue 14:209–217
Amos B, Schlötterer C, Tautz D (1993b) Social structure of pilot whales revealed by analytical DNA profiling. Science 260:670–672
Andersen LW (1988) Electrophoretic differentiation among local populations of the long-finned pilot whale, Globicephala melaena, at the Faroe Islands. Can J Zool 66:1884–1892
Andersen LW (1993) Further studies on the population structure of the long-finned pilot whale, Globicephala melas, off the Faroe Islands. Rep Int Whal Comm Spec Issue 14:219–231
Auger-Méthé M, Whitehead H (2007) The use of natural markings in studies of long-finned pilot whale (Globicephala melas). Mar Mammal Sci 23:77–93
Baird RW, Whitehead H (2000) Social organization of mammal-eating killer whales: group stability and dispersal patterns. Can J Zool 78:2096–2105
Balbuena JA, Raga JA (1994) Intestinal helminths as indicators of segregation and social structure of pods of long-finned pilot whales (Globicephala melas) off the Faeroe Islands. Can J Zool 72:443–448
Barrett-Lennard LG (2000) Population structure and mating patterns of killer whales, Orcinus orca, as revealed by DNA analysis. Ph.D. thesis, University of British Columbia, Vancouver
Bejder L, Fletcher D, Bräger S (1998) A method for testing association patterns of social animals. Anim Behav 56:719–725
Bigg MA (1982) An assessment of killer whale (Orcinus orca) stocks off Vancouver Island, British Columbia. Rep Int Whal Comm 32:655–666
Bigg MA, Olesiuk PF, Ellis GM, Ford JKB, Balcomb KC (1990) Social organization and genealogy of resident killer whales (Orcinus orca) in the coastal waters of British Columbia and Washington State. Rep Int Whal Comm Special Issue 12:383–405
Cairns SJ, Schwäger SJ (1987) A comparison of association indices. Anim Behav 35:1454–1469
Cañadas A, Sagarminaga R (2000) The northeastern Alboran Sea, an important breeding and feeding ground for the long finned pilot whale (Globicephala melas) in the Mediterranean Sea. Mar Mammal Sci 16:513–529
Caurant F, Amiard JC, Amiard-Triquet C, Sauriau PG (1994) Ecological and biological factors controlling the concentrations of trace elements (As, Cd, Cu, Hg, Se, Zn) in delphinids Globicephala melas from the North Atlantic Ocean. Mar Ecol Prog Ser 103:207–219
Caurant F, Amiard-Triquet C, Amiard JC (1993) Factors influencing the accumulation of metals in pilot whales (Globicephala melas) off the Faroe Islands. Rep Int Whal Comm Spec Issue 14:369–390
Christal J, Whitehead H (2001) Social affiliations within sperm whale (Physeter macrocephalus) groups. Ethology 107:323–340
Christal J, Whitehead H, Lettevall E (1998) Sperm whale social units: variation and change. Can J Zool 76:1431–1440
Connor RC (2000) Group living in whales and dolphins. In: Mann J, Connor RC, Tyack PL, Whitehead H (eds) Cetacean societies: field studies of dolphins and whales. University of Chicago Press, Chicago, pp 199–218
de Stephanis R (2008) Estrategias de alimentacio’n de los diferentes grupos de caldero’n comu’n en el Estrecho de Gibraltar. PhD thesis, University of Cadiz
de Stephanis R, Cornulier T, Verborgh P, Salazar Sierra J, Perez Gimeno N, Guinet C (2008) Summer spatial distribution of cetaceans in the Strait of Gibraltar in relation to the oceanographic context. Mar Ecol Prog Ser 353:272–288
Efron B, Gong G (1983) A leisurely look at the bootstrap, the jackknife, and cross-validation. Am Stat 37:36–48
Ford JKB (1989) Acoustic behaviour of resident killer whales (Orcinus orca) off Vancouver Island, British Columbia. Can J Zool 67:727–745
Ford JKB (1991) Vocal traditions among resident killer whales (Orcinus orca) in coastal waters of British Columbia. Can J Zool 69:1454–1483
Ford JKB, Ellis GM (2002) Reassessing the social organization of resident killer whales in British Columbia Fourth International Orca Symposium and Workshop, France, pp 72–74
Ford JKB, Ellis GM, Balcomb KC (2000) Killer whales, 2nd edn. UBC, Vancouver
Fullard K (2000) Microsatellite analysis of long-finned pilot whales. PhD thesis, Cambridge University, Cambridge
Fullard K, Early G, Heide-Jørgensen MP, Bloch D, Rosing-Asvid A, Amos W (2000) Population structure of long-finned pilot whales in the North Atlantic: a correlation with sea surface temperature? Mol Ecol 9:949–958
Ginsberg JR, Young TP (1992) Measuring association between individuals or groups in behavioural studies. Anim Behav 44:377–379
Gosling LM, Petrie M (1981) The economics of social organization. In: Townsend CR, Calow P (eds) Physiological ecology: an evolutionary approach to resource use. Blackwell Scientific, Oxford, UK, pp 315–345
Greenwood PJ (1980) Mating systems, philopatry, and dispersal in birds and mammals. Anim Behav 28:1140–1162
Heimlich-Boran JR (1993) Social organization of the short-finned pilot whale, Globicephala macrorhynchus, with special reference to the social ecology of delphinids. PhD thesis, Cambridge University, Cambridge
Hinde RA (1976) Interactions, relationships and social structure. Man 11:1–17
Jankowski M (2005) Long-finned pilot whale movement and social structure: residency, population mixing, and identification of social units, Master’s thesis, Department of Biology, Dalhousie University, Halifax, Nova Scotia
Manly BFJ (1994) Multivariate statistical methods: a primer, 2nd edn. Chapman & Hall, New York
Ottensmeyer CA, Whitehead H (2003) Behavioural evidence for social units in long-finned pilot whales. Can J Zool 81:1327–1338
Rosel PE (2003) PCR-based sex determination in Odontocete cetaceans. Conserv Genet 4:647–649
Sanz JL, Acosta J, Herranz P, Palomo C, San Gil C (1988) Mapa Batimétrico del Estrecho de Girbaltar. Proyecto Hércules 1980–1983, Instituto Español de Oceanografía
SEC (Sociedad Española de Cetáceos) (1999) Recopilación, Análisis, Valoración y Elaboración de Protocolos sobre las Labores de Observación, Asistencia a Varamientos y Recuperación de Mamíferos y Tortugas Marinas de las Aguas Españolas. Ministerio de Medio Ambiente Español. Secretaria General de Medio Ambiente, Technical Report Sociedad Española de Cetáceos Available from SEC, Nalón 16, E-28240 Hoyo de Manzanares, Madrid, Spain
Shane SH, McSweeney D (1990) Using photo-identification to study pilot whale social organization. Rep Int Whal Comm Spec Issue 12:259–263
Shaw CN, Wilson PJ, White BD (2003) A reliable molecular method of gender determination for mammals. J Mammal 84:123–128
Verborgh P, de Stephanis R, Pérez S, Yaget J, Barbraud C, Guinet C (2008) Abundance and residency of long-finned pilot whales between 1999 and 2005 in the Strait of Gibraltar. Mar Mammal Sci (in press)
Whitehead H (1995) Investigating structure and temporal scale in social organizations using identified individuals. Behav Ecol 6:199–208
Whitehead H (1997) Analysing animal social structure. Anim Behav 53:1053–1067
Whitehead H (1999) Testing association patterns of social animals. Anim Behav 57:F26–F29
Zachariassen P (1993) Pilot whale catches in the Faroe Islands, 1709–1992. In: Biology of Northern Hemisphere Pilot Whales. Rep. Int. Whal. Comm, Cambridge, IWC, pp 69–88