habitat_narrative
Marine
Tursiops truncatus is commonly accepted as the openwater form of the bottlenose dolphin. However, there are many exceptions to this rule, and this species may also be frequently located within shallower waters, nearer to the coast. Presumably though, T. truncatus generally makes use of deeper reefs further offshore, whereas T. aduncus is restricted to shallower inshore areas (Hale et al. 2000). Studies off the coast of North America found that this species is generally associated with waters exhibiting surface temperatures between 10°C and 32°C (Wells & Scott 1999). Common Bottlenose Dolphins form schools of between 3â100 individuals, with a general average of approximately 22, and are often associated with other cetacean species, for example the Long-finned Pilot Whale (Globicephala melas) and the False Killer Whale (Skinner & Chimimba 2005).The stomach contents of two T. truncatus individuals from the Eastern Cape revealed that the dominant prey species was squid (Oregoniateuthis), with hake (Merluccius spp.) and Buttersnoek (Lepidpus caudatus) making up lesser proportions (Ross 1977, 1984). The results from these studies indicate that T. truncatus feeds further offshore when compared to T. aduncus, at least off the Eastern Cape coast (Ross 1984). Off the Western Cape, Sekiguchi et al. (1992) recorded that the diet of T. truncatus comprised of cephalopods (mostly the Cape Hope Squid, Loligo vulgaris reynaudii), and a wide variety of fish (dominated by Southern Mullet, Liza richardsonii, and Cape Horse Mackerel, Trachurus trachurus capensis). Leatherwood (1975) describes the high degree of plasticity associated with feeding behaviour of Tursiops spp. along the west coast of North America, including echolocation techniques, cooperative hunting, and the exploitation of anthropogenic fishing activities (such as depredation).
Mother and calf associations may last as long as 3 to 4 years (Bearzi et al. 1997), which may be a general reflection of the inter-birth interval exhibited by female Common Bottlenose Dolphins. Although, females usually only breed every 3â6 years, Connor et al. (2000) described intervals of 2 years off the coast of Florida. Model-based estimates of generation time are 21.1 years (Taylor et al. 2007).
Ecosystem and cultural services: This is the archetype of dolphins and, since most South Africans are unaware of the variety of delphinids, this is typically what they envisage when âdolphinsâ are mentioned.
