Bunbury summer dolphin transects complete

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Summer season field work complete Over the summer season (December- February) we encountered 62 dolphin groups. We were on the boat for 25 days (> 144 hours), completing:

  • Six replicates of each of the Inshore, Backbeach and Buffalo Beach transects;  and
  • Three replicates of the Busselton, Backbeach offshore and Buffalo Beach offshore transects (see study site map).

Dolphins observed offshore:
On our offshore transects, we observed dolphins on two occasions:

  1. On the Backbeach offshore transect we encountered a group of females and calves 4km offshore (including Jazz, Chopper, Munch and Oz; Slope and Matrix; Pearl and Sapphire).
  2. On the Buffalo offshore transect we encountered dolphins for the very first time. The group was a mixed group of calves, adult females and adult males. This was the first time we have observed adult males on an offshore transect (males included Trigger, Bob, Wallace and Vandal). Very exciting!

Mapping the benthic habitat:
To ground truth the benthic habitat we have selected 150 points over the study area where we drop a 1m x 1m metal quadrate frame into the water. Attached to the top of the frame is an underwater camera that is connected to the laptop on the boat. Video and pictures are recorded of the sea floor and at the same time GPS position, depth, turbidity and weather conditions are noted. In February, we recorded 30 of these points. The images are then processed before validating remotely sensed satellite images. From the satellite images a benthic habitat map of the study area will be created using program ArcGIS. Ultimately, through mapping the benthic habitat, any relationship between habitat and dolphin distributions can be drawn.

Fraggle’s new born calf, Sachin.

Birthing season:
Over the summer there were seven new dolphin births. The mother dolphins are Slope, Zenith, Fraggle, Munch, Pearl, Scout and Dane. Holly Smith, the previous PhD student with the South West Marine Research Program (SWMRP), found that the peak calving season for the Bunbury dolphins is in March, so hopefully many more baby dolphins will be born over the autumn season.

Dolphin calf missing:
In mid January, Levy, a common provisioned dolphin at the Dolphin Discovery Centre, was observed being harassed by adult males. After this, Levy was the bearer of new rake marks (scars from dolphin teeth).  Levy’s seven month old calf, Twilight, was also noted missing. Unfortunately, Twilight has not been seen since.

Dolphin leaping in Koombana Bay, Bunbury.

South West Marine Research Program acknowledgements:
We currently have three dedicated assistants for the SWMRP; Welmoed from Holland, Catharina from Germany and Sarah from Canada. Interns who have recently finished with SWMRP were Cam, Niels and Nathasja. Thank you very much for your assistance.

This research is made possible through the partners of the SWMRP, including, the Bunbury Dolphin Discovery Centre, Bemax Cable Sands, BHP Billiton Worsley Alumina, Bunbury Dolphin Discovery Centre, Bunbury Port Authority, City of Bunbury, Cristal Global, Department of Environment and Conservation, Iluka, Millard Marine, Naturaliste Charters, Newmont Boddington Gold, South West Development Commission and WAPRES.

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