Revive Our Gulf has partnered with Kelly Tarlton’s Marine Wildlife Trust to investigate what seaweed species can assist in the settlement of young green-lipped mussels.
The research aims to verify what local seaweeds – from the Hauraki Gulf Marine Park – are likely to provide a suitable structure for the primary settlement of green-lipped mussel larvae.
We’ll then investigate the potential for transplanting those seaweed species with attached larvae into the sea.
Importance of seaweeds
Mussels are broadcast spawners; the eggs and sperm of adult mussels are released into the water column and combine to form pelagic larvae that float in the ocean for weeks until ready to settle.
These late-stage mussel larvae eventually look to settle on filamentous structureslike seaweeds (filamentous means threadlike or ropey, usually many times longer than wide).
The initial movement of mussels from the water column to fine, filamentous structures is called primary settlement. A series of further migrations are made as mussels grow (‘secondary settlement’), until the juveniles find their way back to an adult mussel bed or other suitable seafloor habitat.
We know that mussels exist in the water column of the Gulf, but they aren’t forming adult beds. This means there is a ‘bottleneck’ in the lifecycle of green-lipped mussels, and it’s possible that a lack of settlement structure (like seaweeds!) could be a limiting factor in mussel recruitment. Gaining a better understanding of this process, the timing, and settlement preferences of mussel larvae on different types of seaweeds could help restoration practitioners at Revive Our Gulf get more mussels to thrive on the seafloor.
 Alfaro & Jeffs 2002, 2003; Alfaro et al. 2004, Green-lipped Mussels in GLM 9, New Zealand Fisheries Assessment Report 2011/48, November 2011
Frequently Asked Questions
Why are we doing this?
For mussel restoration efforts to be successful on a large scale, we need to cultivate the conditions for mussels to breed naturally in place.
We know that green-lipped mussel larvae will choose to settle on filamentous seaweed. What we don’t yet know is whether there are seaweeds that are preferable, and whether we can successfully hold these in tanks to support mussel reef restoration efforts.
The more that we understand about primary settlement, the more we’ll be able to support the conditions for the mussels to have the best chance of reproducing naturally.
Why Kelly Tarlton’s?
The Kelly Tarlton’s Marine Wildlife Trust is a registered environmental non-profit organisation dedicated to rescue, rehabilitation of sick or injured marine wildlife and increasingly the care and restoration of the Hauraki Gulf.
Kelly Tarlton’s has experience with aquariums and is building dedicated aquariums to home the various seaweed species collected from the Hauraki Gulf.
Kelly Tarlton’s is also located right in the epicentre of one of our restoration sites – Ōkahu Bay.
Who else is involved?
Kelly Tarlton’s will lead the research and work with Revive Our Gulf, Ngāti Whātua Ōrakei and the Institute of Marine Science at the University of Auckland.
How long will the project run?
The research will be undertaken throughout 2023.
Talking mussels on RNZ
Kathryn Ryan from RNZ’s Nine to Noon spoke with global Aquarium industry consultant, and trustee with Kelly Tarlton Marine Wildlife Trust, Craig Thorburn, who is managing the mussel spat experiment and Ngāti Whātua Ōrākei general manager for the environment/Pou Taiao, Kingi Makoare. Don’t miss out on this important conversation about shellfish restoration in the Hauraki… Read more »
18 April 2023
Our team on Newshub
Revive Our Gulf has teamed up with Kelly Tarlton’s Marine Wildlife Trust for an important research project. Check out this Newshub coverage to hear from some of the team. https://www.newshub.co.nz/home/new-zealand/2023/04/baby-mussels-in-hauraki-gulf-no-longer-growing-together-in-large-numbers-but-researchers-may-have-solution.html
14 April 2023
40,000 mussel larvae
On March 14th, Dr. Mallory Sea (Project Coordinator at Kelly Tarltons Marine Wildlife Trust) flew down to the South Island to meet with mussel experts at the SpatNZ hatchery in Nelson. This facility selectively breeds green-lipped mussels to produce a consistent and reliable supply of spat (baby mussels) for the aquaculture industry—but while the typical… Read more »
20 March 2023