Dolphin sympatric ecology

Abstract

Interspecific associations between two or more species of the family Delphinidae have been reported by many scientists, but the sympatric ecology of such dolphin associations has not been studied in great detail. A few field investigations have been conducted on this subject in different parts of the world on species such as bottlenose dolphins (Tursiops spp.), short-beaked common dolphins (Delphinus delphis ), and killer whales (Orcinus orca ). Sympatric dolphins seem to use different strategies to co-exist when resources appear to be limited, including dietary divergence (different prey preference, slightly diverse diet, different feeding time) and/or different habitat use (shallow versus deep waters, flat areas versus submarine canyons and escarpments, different travel routes). This paper presents a review of some well-studied dolphin species found in sympatry and discusses the nature of habitat and resource partitioning as well as studies on aggressive behaviour displayed by species living in the same habitat.

Modeling habitat use for dusky dolphin and Commerson’s dolphin in Patagonia

“…Such habitat partitioning has been observed in many marine species (Gowans & Whitehead 1995). Alternatively, species may be able to coexist as a result of dietary differences or by using the area for different functions, so that they do not exert a strong competitive pressure on each other (Bearzi 2005).…”

“…Several studies have described cetaceans' distribution and habitat preferences by linking their presence to different habitat variables (Forcada 2002). Such variables include sea temperature (Brown & Winn 1989, Baumgartner et al 2001, Cañadas et al 2005, Panigada et al 2008, Garaffo et al 2010, bathymetric and physiographic variables (Baumgartner 1997, Carretta et al 2001, Cañadas et al 2002, 2005, Torres et al 2003, Panigada et al 2005, 2008, Garaffo et al 2007, 2010, Ingram et al 2007, Bailey & Thompson 2009, Embling et al 2010, currents and frontal systems (Tynan 1998, Mendes et al 2002, Johnston et al 2005a,b, Pedraza 2008, primary production (Littaye et al 2004, Panigada et al 2008, Garaffo et al 2010, and prey distribution (Jaquet & Gendron 2002, Baumgartner et al 2003, Macleod et al 2004.…”

Prey consumed by Guiana dolphin Sotalia guianensis (Cetacea, Delphinidae) and franciscana dolphin Pontoporia blainvillei (Cetacea, Pontoporiidae) in an estuarine environment in southern Brazil

“…In contrast to the Guiana dolphin, the franciscana does not commonly occur in estuarine areas, with the exception of Babitonga Bay in south Brazil (Cremer & SimõeS-LopeS, 2005). In this area, both dolphins live in direct sympatry (sensu Bearzi, 2005), but they were never seen together (Cremer & SimõeS-LopeS, 2008). The franciscana population is smaller than the Guiana dolphin population in this area, being estimated at 50 and 208 individuals, respectively (Cremer & SimõeS-LopeS, 2008;Cremer et al, 2011).…”

Near-Shore Distribution of Heaviside's (Cephalorhynchus heavisidii) and Dusky Dolphins (Lagenorhynchus obscurus) at the Southern Limit of their Range in South Africa

“…Competition between sympatric cetaceans may be mediated more subtly by resource partitioning including differences in fine-scale habitat selection and prey species taken (Bearzi 2005;Parra et al 2005;Heinrich 2006). There is some evidence to suggest that the two species in the current study occupy different niches, as they respond to different environmental cues (Elwen et al 2009) and eat different species and sizes of prey (Sekiguchi et al 1992) although with a significant amount of overlap.…”