Observations on inshore and pelagic Dolphins on the South-Eastern Cape coast of South Africa

Saayman, Graham S.; Bower, D. M.; Tayler, C. K.

doi:10.4102/koedoe.v15i1.664

Cited by 32 publications

(19 citation statements)

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“…There is no known gene flow between shortbeaked common dolphins and long-beaked common dolphins, and they occur sympatrically in tropical Cape coast of south Africa Saayman et al 1972 and temperate waters (Heyning & Perrin 1994;Rice 1998). In Santa Monica Bay, California, the direct sympatric ecology of short-beaked common dolphins and long-beaked common dolphins was investigated (Bearzi 2003).…”

Section: Bottlenose Dolphins and Indo-pacific Bottlenose Dolphinsmentioning

confidence: 99%

Dolphin sympatric ecology

Bearzi

2005

Marine Biology Research

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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.

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Section: Bottlenose Dolphins and Indo-pacific Bottlenose Dolphinsmentioning

confidence: 99%

Dolphin sympatric ecology

Bearzi

2005

Marine Biology Research

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“…Saayman, Bower & Tayler, 1972). One interesting possibility in the pelagic environment is for predation risk to be vertically strati®ed because of changes in light level and the vertical strati®cation of shark species.…”

Section: Odontocete Behavioural Responses To Shark Predation Riskmentioning

confidence: 99%

Predator–prey and competitive interactions between sharks (order Selachii) and dolphins (suborder Odontoceti): a review

2001

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The importance of interactions between sharks and cetaceans has been a subject of much conjecture, but few studies have addressed these interactions. Sharks (order Selachii) have been hypothesized to be important predators on dolphins and porpoises (suborder Odontoceti). Unfortunately, there are often few data to back up claims that certain shark species are major threats to cetaceans. To help identify potential shark predators in speci®c locations, available data on interactions with odontocetes for all shark species that may include cetaceans in their diet are reviewed. Shark species are categorized into groups based on predatory interactions with dolphins and porpoises (regular predators, occasional predators, potential predators, ectoparasites and insuf®cient data). Several shark species that have been overlooked in the cetacean literature are identi®ed as potentially important predators while others that have been suspected to be important predators are probably at most occasional predators. How shark predation can in¯uence dolphin populations, habitat use, group size and behaviour is discussed. How risk of shark predation can vary with habitat attributes in both nearshore and pelagic waters is also discussed. Predator±prey interactions have been the focus of most studies of shark±dolphin interaction, but competitive interactions may also occur. The ®rst analysis of shark±dolphin dietary overlap is presented, which shows it to be signi®cant between common dolphins and several species of sharks, including species that prey upon these dolphins.

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“…While cetaceans present particular methodological challenges (Mann ), activity budget data have shed light on the relationship between behavior and prey ecology, bathymetry, tidal state, time of day, season, and survival (Saayman et al . ; Shane , ; Ballance ; Bräger ; Hanson and Defran ; Mann and Watson‐Capps ; Steiner ). Several studies have also found links between cetacean activity budgets and human interactions and disturbances (Bejder et al .…”

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confidence: 99%

A comparison of survey and focal follow methods for estimating individual activity budgets of cetaceans

Karniski

Patterson

Krzyszczyk

et al. 2014

Marine Mammal Science

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Activity budget data are essential for determining behavioral responses to physiological and ecological variables. Yet, few studies are available to investigate the robustness, accuracy, and biases of the methods used to estimate activity budgets for cetaceans. In this study, we compare activity budgets of 55 adult female bottlenose dolphins in Shark Bay, Australia derived from two methods: surveys (n = 6,903) and focal follows (n = 1,185, totaling 2,721 h of observation). Activity budgets estimated from survey data differed in all behavioral states compared to focal follow data. However, when controlling for temporal autocorrelation, only time spent socializing and time spent traveling remained disparate between the methods. To control for biases associated with assigning group‐level behavior to individuals, we also compared survey and focal follow activity budgets for lone females. Here we found differences between methods in time spent foraging and traveling regardless of whether we controlled for temporal autocorrelation, which suggests detection biases likely play a role in explaining differences in activity budget estimates between the two methodologies. Our results suggest that surveys are less representative of individual‐level activity budgets, and thus, when individual‐level knowledge about behavior is needed, focal follows are preferred.

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Observations on inshore and pelagic Dolphins on the South-Eastern Cape coast of South Africa

Cited by 32 publications

References 0 publications

Dolphin sympatric ecology

Dolphin sympatric ecology

Predator–prey and competitive interactions between sharks (order Selachii) and dolphins (suborder Odontoceti): a review

A comparison of survey and focal follow methods for estimating individual activity budgets of cetaceans

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