Megafauna-galore in Hawai’i !!
This month (June 2012) concluded the 21st month of photographic identification effort of Hawaiian spinner dolphins along the Kona coast of Hawai’i Island.The SAPPHIRE dolphin catalogue now includes 620 distinctive individuals. Over the past three months (April-June), we have been on the water for 42 days (365 hours). Of these, 36 days were spent photo-identifying spinner dolphins. In this time period, we took more than 25,000 images of spinner dolphins. We spent six days retrieving and deploying our acoustic loggers. Since we commenced the SAPPHIRE project in September of 2010, we have spent a total of 252 days on the water carrying out photographic identification, amounting to 182,000 images. Furthermore, we have in excess of 6,000 hours of acoustics recordings from four resting bays along the Kona coast.
Click here to listen to spinner dolphin vocalisations
Spinner dolphin (Stenella longirostris) mother, calf and remora
False killer whales (Pseudorca crassidens)
Makako Bay (our northern most study site) has been featuring large spinner dolphin groups on a regular basis since January 2012. Here, dolphin group sizes typically range in the hundreds, and this month was no exception. Each encounter is unique with group sizes fluctuating from month to month, day to day, and even hour to hour. During a survey in Makako Bay on the 18th of March we were conducting an approach towards a group of spinner dolphins for photo-identification.Suddenly, the group of dolphins changed direction and we observed an increase in surface and aerial behaviours. To our surprise we then noticed several false killer whales where the group of spinners had been only moments earlier.
False killer whale (Pseudorca crassidens) in Makako Bay
Rough-toothed dolphins (Steno bredanensis) and hammerhead sharks
Furthermore, since March 2012, we have sighted several other marine species during our spinner dolphin research, including hammerhead sharks , bottlenose dolphins, spotted dolphins, and most recently, a sighting of two oceanic white tip sharks following a group of rough-toothed dolphins.
Rough toothed dolphins (Steno bredanensis) along the Kona coast, Hawai’i
Focal follow, from left to right Laura Ceyrac, Miriam Battye and Tasha Boerst
In June, we have undertaken two focal follows; during focal follows we run transect either north or south out of Keauhou Bay (our primary boat launch point) and look for spinner dolphin groups.
When a dolphin group is encountered, we collect photographic identification data before conducting behavioural surveys. Behavioural surveys record the general group behavioral state, position, potential sources of anthropogenic influence (including our own boat), and the continuous recording of 13 conspicuous behaviour events for the duration of time with the focal dolphin group.
The SAPPHIRE project would like to say a big thank you to John Symons, who has been helping out on the project since April 2011. Since the end of January 2012, John has been running the field season for Julian until he returns to Kona in July for another six months. It is with great pleasure that we can inform you that John has been accepted into a postgraduate Masters program at University of Aberdeen, Scotland, and we wish him the very best of luck in his endeavours.
