Katina Conomos Main speaker at our meeting on 21 January was Katina Conomos who is Executive Director of Revive our Gulf. Katina spoke to us about the work being done to revive mussel beds in the Hauraki Gilf. She took us through what has been happening in the gulf and what lessons have been learned from what has been done to date. In 2020 resource consent was obtained to rebuild mussel beds leading to about 60tonnes of mussels being placed into the water at Okahu bay and more recenty in the Kawau area adjacent to the Moturekareka and Motuketekete Islands. Of the mussels laid in Okahu bay there was a 95% mortality rate over two years but a seeming increase in biodiversity in the areas where the mussels were laid. An issue was deposition of sediment, about 2 centemeters over the mussels derived from runoff from catchment surrounding Okahu Bay and the wider Waitemata Harbour. Cyclone Gabrielle also had an impact on mortality Mortality of the mussels laid in the Kawau area varied but it still wasn’t good. On the plus side biodiversity improved around the sites. Juvenile snapper seem to use the mussel beds (in the Kawau area) as nursery’s. One down side is that no natural recruitment of mussels has been identified but it is early days and the revival work is work in progress as people find what works and what does not. Recently mussels wers deployed in the the Beachlands, Ponui, Rotoroa Island area in conjunction with Ngai Tai ki Tamaki. 8 sites were used so researchers in the future will be able to see what environments are best suited to the revival work. Katina noted ROVs are being used more and more to survey mussel sites saving divers time and effort. Katina also comented that Caulerpa is an issue that is being looked at as it will impact the mussell restoration program. One of Katina’s team is looking at it on a full time basis. Unhappoily that is a growth area as Caulerpa spreads throughout the marine environment. A interesting address on a subject dear to members hearts. |
