Te Whai RaHI
Photo credit: Mark Erdmann
Globally, te whai rahi oceanic manta rays are endangered with some populations in serious decline, but here in New Zealand we simply don’t know enough about how these impressive ocean voyagers are faring in a rapidly changing ocean. Data, sightings and knowledge are crucial to ensuring a healthy future for the great oceanic manta.
With powerful wingspans of up to seven meters wide, these ocean wanderers don’t let their enormous two-tonne frame weigh them down, gracefully flying across the Pacific. Big brained and highly social these New Zealand manta are unsung champions – holding the triple crown for the longest recorded migration path, deepest recorded dive and going to the coldest water ever recorded for any manta.
Mātauranga Māori shows Aotearoa has been a home for te whai rahi for centuries, yet a lot of mystery still surrounds these manta. The research team at Manta Watch New Zealand, led by Dr Lydia Green are working hard to find answers. By bringing together knowledge, tracking data and public sightings, they’re developing a clear picture of the population size, movements, and the role of New Zealand’s waters in the manta’s lifecycle.
“Citizen scientists play a massive role in targeting our research efforts and contributing to our collective understanding of this lesser-known population.”
– Lydia Green
Traditionally considered to be a tropical species, many people see manta as visitors passing through rather than a local in New Zealand’s waters. Manta Watch NZ’s first major breakthrough in changing this mindset was with Emmy the manta, who they met off the coast of Whangaroa in 2019.
The research team followed her 1,982 km record-breaking journey to Fiji. Her tag popped off in the Pacific, however she was sighted again near Te Hauturu-ō-Toi Little Barrier Island the following summer. Emmy’s voyage provided much-needed evidence that her presence in New Zealand is both intentional and a key location in her annual migration.
This breakthrough unlocked more questions than answers, highlighting how much more there is to learn around migration routes if we are to identify risks and implement protection measures.
DEEP DIVE INTO
THE TWILIGHT ZONE
Not only did Emmy win the record for the longest migration, she also took the prize for the deepest dive – recorded as reaching 1,248 metres!
This is far deeper than previously thought and shows a connection to the deep ocean ‘twilight’ and ‘midnight’ zones. While many marine species spend time in these zones, we know relatively little about them. Learning what the manta are doing when they go deep could help researchers monitor the overall health and changes within these ecosystems.
HELP SOLVE THE
MYSTERY OF THE MANTA
1. REPORT YOUR SIGHTINGS
If you’re lucky enough to spot one of these majestic giants while out on the moana, please let the Manta Watch team know.
Photos are incredibly valuable, especially of their belly, when it comes to helping identify individuals, so if it’s safe for you and the marine life to grab a pic please do.
2. SUPPORT THE RESEARCHERS
If you aren’t able to look for manta yourself, you can help the team by providing much needed research support, such as increased boat time and satellite trackers.
100% of all donations through Live Ocean Foundation until 15 December will go directly to Manta Watch New Zealand.
Photo credit: Rebecca Pratt