HABITAT USE AND PREFERENCES OF INDO-PACIFIC HUMPBACK DOLPHINS SOUSA CHINENSIS IN ALGOA BAY, SOUTH AFRICA

By Leszek Karczmarski, V. Cockcroft, A. Mclachlan. 2000

183 citations recorded by the source corpus.

This paper examines environmental and behavioral determinants of the habitat use and preferences of Indo-Pacific humpback dolphins inhabiting the Algoa Bay region on the south Eastern Cape coast of South Africa. In order to quantify the habitat use and preference, two indices were used, the Coefficient of Area Use (AU) and the Activity Index (AI). The dolphins inhabit a narrow strip of shallow, inshore waters of Algoa Bay and remain mostly within 400 m of the shore, in water less than 15 m deep, with no apparent preference for clear or turbid water. Water depth is probably the main factor limiting their inshore distribution, and the 25-m isobath seems to represent the critical depth. Within this confined, inshore distribution, dolphin activities concentrate in the vicinity of rocky reefs-their primary feeding grounds. Dolphin dependence on these shallow-water habitats is evident throughout the year and, consequently, the inshore shallow reefs are identified as the “key habitat” which is of primary importance for humpback dolphins in Eastern Cape waters. The dolphins' dependence on this restricted type of habitat within an already restricted inshore distribution makes them particularly vulnerable to alteration or loss of this habitat.

Subfields: Developmental Biology, Ecology, Genetics

View Paper: https://www.semanticscholar.org/paper/370cc2ff5a158c695a7de26656caef513db92ccb

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Citations in the corpus

Habitat selection in a coastal dolphin species (Cephalorhynchus hectori) (2003, background): “The effect of water clarity on habitat use by dolphins is more difficult to measure and no studies have detected a clear preference for turbid waters (Maze and Wu¨ rsig 1999; Karczmarski et al. 2000 ).”
Spatial distribution and environmental correlates of Australian snubfin and Indo‐Pacific humpback dolphins (2006, background): “The exception to this is off the coast of South Africa ( Karczmarski et al. 1999, 2000, Keith et al. 2002) and in Hong Kong waters (Jefferson 2000) where humpback dolphins have been relatively well studied.”
Distribution, abundance and conservation status of the eastern Taiwan Strait population of Indo-Pacific humpback dolphins, Sousa chinensis (2007, background): “…can best be described as more or less one-dimensional and resembles that of humpback dolphins off South Africa where a similar environment (small river estuaries entering a narrow stretch of shallow coastal waters along a linear coastline) exists (Saayman and Tayler 1979, Karczmarski et al. 2000).”
Functional mechanisms underlying cetacean distribution patterns: hotspots for bottlenose dolphins are linked to foraging (2004, background): “…habitat features (Watts and Gaskin 1986; Ross et al. 1987; Selzer and Payne 1988; Frankel et al. 1995; Gowans and Whitehead 1995; Baumgartner 1997; Raum-Suryan and Harvey 1998; Karczmarski et al. 2000; Davis et al. 2002), but the underlying function of the preferred habitats often remains unclear.”
POPULATION SIZE, DISTRIBUTION, AND BEHAVIOR OF INDO‐PACIFIC BOTTLENOSE (TURSIOPS ADUNCUS) AND HUMPBACK (SOUSA CHINENSIS) DOLPHINS OFF THE SOUTH COAST OF ZANZIBAR (2006, methodology): “This distribution of humpback dolphins is similar to that described in other areas such as Algoa Bay, South Africa, where the humpback dolphins seldom venture further than 500 m from shore (Karczmarski et al. 2000).”
Fine-scale habitat selection by coastal bottlenose dolphins: application of a new land-based video-montage technique (2003, unknown): “Distribution patterns have been frequently correlated with underwater topography, such as water depth (Watts and Gaskin 1986; Ross et al. 1987; Frankel et al. 1995; Gowans and Whitehead 1995; Baumgartner 1997; Davis et al. 1998; Raum-Suryan and Harvey 1998; Karczmarski et al. 2000) and seabed gradie”
Confusion reigns? A review of marine megafauna interactions with tidal-stream environments (2015, background): “Humpbacked dolphins (Sousa spp.) are highly coastal in their distribution and are often associated with estuaries and embayments (e.g. Karczmarski et al. 2000, Jefferson & Karczmarski 2001, Chen et al. 2010, Bijukumar & Smrithy 2012, Lin et al. 2013).”