2018 Port Stephens Dolphin Census Results

Thank you to everyone who participated in the 18th Annual Port Stephens Community Dolphin Census, 29th July 2018. With poor weather resulting in the cancellation of the June event, we were nervously watching forecasts ahead of the second count. As it turned out, we couldn’t have had better conditions for sightings; the winds stayed down, much of the bay was glassed out and a cloudy sky helped to diffuse light, ultimately allowing for great visibility across the bay.

103 dolphins were sighted throughout the morning, including some well known individuals. This included residents such as Favourite and her offspring who were seen travelling between Nelson Head and Fly Point. Sunny and her 7 month old were seen near the Anchorage marina (this pair of marina hoppers are also frequently sighted inside Nelson Bay marina). Scream and her calf were spotted near Pindimar, while Cutfin, Splitfin and PS320 were all sighted fishing with their calves along the shoreline outside North Arm Cove. The largest pod encountered, a group of approximately 18 dolphins (including the Bay’s largest alliance of 9 males and a mum and calf) was sighted from a vessel leaving Tilligerry Creek just before the census period, this group dispersed as they left the creek. Members of this pod were later observed by additional vessels, foraging and tracking past Bull Island/Mud Point.

Figure 1: Census results from eighteen Port Stephens community dolphin surveys showing the number of dolphins sighted (blue columns) and the number of annual participants (red line).

Figure 1 provides an overview of dolphin sightings and community participation over the past eighteen years. This year, 96 participants were located across 66 sites around Port Stephens. Shore participation was well spread along most of the Port, however there were still vacant areas up Tilligerry Creek, through Swan Bay and on the Northern side of the bay towards Karuah. These areas were a point of focus for some of our volunteer vessels.

The census count of 103 dolphins is higher than the average count of 90 achieved over the 18 year census period (with a range of 12 dolphins in 2011 to 194 dolphins in 2004). This was an excellent outcome for this year’s event, however we do not believe that it is reflective of any greater trends in population health. Higher participation and site coverage then recent years and good weather likely influenced the result. 18 of 50 occupied shore sites recorded sightings during the census period and 8 of 15 vessels also recorded positive sightings. 15 sites recorded a common sighting (same dolphin/s seen by more than 1 location), with 28 dolphins seen by those respective locations. These sightings were considered when consolidating results (131 positive sightings- 28 common sightings= 103 dolphins).

Figure 2: Created by Michael Haecker, Brightbird Systems. Distribution of sightings throughout 2018 Port Stephens Community Dolphin Census.

Figure 2 shows dolphin counts recorded at each site during this year's census. Green place holders represent occupied land sites, while purple markers indicate on-water locations. Counts for each site are shown in place holders as numeric values. Place holders with no numeric value indicate that a site submitted a report of 'nil sightings'. Sites where reports were not received are not shown on the map.

Past studies conducted by Macquarie University estimate the Port Stephens dolphin population is comprised of approximately 90 individuals, with many more visiting from other areas around the coast. Additionally, an ongoing population study by the Marine Parks Association using photo identification has observed 275 individuals since 2013, with 158 individuals sighted on a regular enough basis to understand social standing. 20 individuals have been identified as regular visitors to the Port, further 5 of those animals have been sighted off Newcastle.

I want to take a moment to reiterate how much I appreciate the support of everyone who participated in the 2018 Port Stephens Community Dolphin Census, including Marine Rescue- Port Stephens, Imagine Cruises and Moonshadow-TQC. We are fortunate to have such a dedicated volunteer base and I’d like to say a big thank you to those of you who lend your support year after year.

The voluntary census is invaluable because it is the longest running community dolphin count in Australia, it helps to form a set of baseline data that directly supports dolphin conservation and studies conducted by research institutes. The value of the census goes beyond the number of dolphins sighted each year as the information collected through the day helps shape our understanding of dolphin distribution and their movements throughout the Port.