Update on the Coastal and Estuarine Dolphin Project – Winter 2012
Fieldwork for the Coastal and Estuarine Dolphin Project (CEDP) has been underway for more than a year now. The project, based in the metropolitan waters of Perth, Western Australia, uses photo-ID and behavioural research to support conservation efforts for bottlenose dolphins in the Perth region.
Gizmo, a three-to-four year old calf from the Swan-Canning Estuary, was first observed with fishing line entangled around his dorsal fin on 28 April 2012. Wildlife Officers from the Department of Environment and Conservation, with the help of the Swan River Trust and Water Police, made numerous efforts to disentangle Gizmo without success. Tupac, the mother, was very protective and obstructed intervention efforts. The Swan River Trust maintained a call-in system to allow people to report sightings of Gizmo, with frequent sightings from Fremantle Ports personnel, Curtin University and Murdoch University researchers, Dolphin Watch volunteers, and community members.
On Friday 22 June 2012, Water Police and DEC were able to apprehend Gizmo on the shore of the Swan River. The entanglement (several meters of fishing line) was removed and, after an assessment by Dr Simone Vitali from the Perth Zoo, Gizmo was released.
Though Gizmo is now free is the question remains – is he really safe when the risk of entanglement in discarded fishing line is so high? Entanglement is the leading cause of human-induced mortality for dolphin calves in the Perth area. This dramatic example definitely explains how it is important to keep the waterways and oceans clean. Please, take all your rubbish with you.
Summary of autumn 2012 surveys
Autumn (March, April and May) has been another challenging season! We thank the Marine and Freshwater Research Laboratory Environmental Science at Murdoch University for letting us using their boat. This season has been marked by a return in abundance of dolphins in the offshore areas (Cockburn Sound, Owen Anchorage and Gage Roads) and the presence of several newborns. Across the five cycles completed in autumn (with one cycle consisting of one survey of each of the four sampling regions), we encountered 24 groups of dolphins (with group sizes of up to 30 individuals). This compares with 16 groups (of generally smaller group size) during the summer sampling period. These differences, if real, may relate to changes in prey abundance and distribution, or other factors.
This research is made possible through the support of a variety of corporate, government, and community partners, including volunteers from the Dolphin Watch project, Fremantle Ports, and the Swan River Trust.