Kōura Hydrophone Deployment
On Sunday 9th October Waiheke Marine Project (WMP), Mana Whenua regenerative divers from Ngāti Pāoa ki Waiheke, Kelly Tarltons Marine Wildlife Trust (KTMWT) and Waiheke Dive set out on a mission to install an Acoustic Hydrophone at Spot-X.
Spot-X is located on the northern coast of Waiheke Island, Hauraki Gulf Tīkapa Moana and has previously been observed as a rare and unique Kōura population, predominantly inhabited by Packhorse Crayfish species in the area.
The acoustic hydrophone records the sounds that occur within the surrounding reef and any action in the area. The device is programmed to record every half hour for 5 minutes for a month-long period. The hydrophone was installed with the help of Auckland University as they kindly loaned the device.
The day began with a karakia delivered by Jeanine Clarkin, a round of whakawhanaungatanga and a briefing, outlining how the diving will unfold. Mana whenua divers from Ngāti Pāoa ki Waiheke, EJ, Noa, Leanne and Leigh boarded Waiheke Dive’s boat ‘Tū Moana’ with captain Adam Whatton journeying out to Spot-X.
The team were briefed on the day to write down any observations that they found using their underwater notebooks. They were instructed to look out for Kōura but also look out for the moult (shells) of the Kōura as you can tell the length and gender of a Kōura from their malt (shell).
Once they arrived at Spot-X Tū Moana anchored up alongside KTMW Trusts’ boat ‘Rhash Decision.’ The divers searched for Kōura while the KTMW team Mitch, Craig and Ebi deployed the hydrophone.Mounted to a 25kg base acting as an anchor for the hydrophone, the team lowered the base into the water. Once in the water the base was placed metres away from the reef entrance, the hydrophone was activated and deployed!
To listen and gather the data, the team will take it out of the mount, connect it up to a computer every 2 weeks. This extension of the Kōura Dive Survey gives us insight into what a healthy Kōura population may look like, and even sound like!