Dolphin population monitoring and habitat modelling

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Lead Researcher

Supervisors

Background

Continued monitoring and development of solid baseline data are necessary for management and conservation efforts for this population. Further, examining variation between the sexes in population parameters such as seasonal abundance, home range size and habitat usage allow for better management practices of the population.

Research aims

  1. Continue long-term monitoring of the population
  2. Assess sex-specific variation in population parameters

Specific objectives

  • Estimate sex-specific patterns in abundance, apparent survival and temporary emigration of dolphins and to investigate fluctuations in population parameters with environmental conditions
  • Investigate sex-specific differences in home range size for adult dolphins and explore whether dolphins could be portioned into groups based on home range size
  • Examine the influence of biotic and abiotic factors on the seasonal spatial distribution and habitat use of adult male and adult female dolphins
  • Discuss sex-specific and seasonal patterns in the local dolphin population and make recommendations for future research directives

Methods

Between 2007 and 2013, year-round standard boat-based photo-identification techniques were used as a capture-recapture method for documenting individual bottlenose dolphins, based on nicks and marks on the dorsal fin and body surface, encountered along pre-determined transect lines.

The study area was expanded from 120 km2 to 540 km2 to six transect zones: the three initial transect zones from the Population abundance and ranging patterns project (Zone 1: Buffalo Beach; Zone 2: Back Beach; and Zone 3: Bunbury Inner waters; Figure 1) and three additional transect zones (Back Beach offshore, Buffalo Beach offshore and Busselton. Surveys were conducted from a 5 m centre console research vessel driven at a speed of 8 -12 kn along transect lines. Transects followed a predetermined track in a zigzag pattern up to five nautical mile from shore.

Map of the 540 km2 study area in the near-shore environment around the Bunbury, Western Australia, showing the extent of the six transect zones and zig-jag patterns of each transect line. Zone 1: the northern area off Buffalo Beach; Zone 2: the southern area off Back Beach; and Zone 3: Bunbury inner waters including the Leschenault Estuary and Inlet, Inner and Outer Harbour, Koombana Bay and the lower reaches of the Collie River. Additional transects were added (Buffalo Beach offshore, Back Beach offshore, and Busselton).

Publications

Completed PhD thesis

Blogs

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