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The Poor Knights Islands (Māori: Tawhiti Rahi) are a marine reserve located 14+ miles off the coast of North Island (Māori: Te Ika-a-Māui), New Zealand. The remote cluster of islands is home to a vibrant ecosystem of marine life and unique bathymetry, including underwater arches, tunnels, and caves. The Poor Knights are revered as one of the foremost recreational diving locations in the world, and have great cultural significance as the historic home of the Ngātiwai people and hapū.
The region, however, is increasingly under threat due to the effects of climate change. Rising ocean temperatures and more frequent and extreme weather are jeopardizing the marine ecosystem, and negatively impacting the coastal communities that interact with it.
As part of a coordinated response, the New Zealand Department of Conservation, multiple academic partners, and Te Whānau a Rangiwhakaahu deployed a Spotter Platform in the Poor Knights to collect and transmit critical surface and subsurface observations in real-time. The data collected by the platform supports marine research, conservation efforts, and recreational activities that are critical to the future of the region.
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The Poor Knights are situated within the East Auckland Current, which drives warm, subtropical water into the region. The current carries with it an array of subtropical species, which combine with existing temperate marine life to form the unique mixture of flora and fauna that attracts divers to the islands. The inflow of warm water, however, also makes the islands uniquely vulnerable to the effects of climate change.
Sea temperatures at the Poor Knights — like sea temperatures around the world — have risen over time, a result of the ocean absorbing excess heat that has been trapped by greenhouse gasses in the atmosphere. As the water has warmed, it has become increasingly hospitable to the subtropical species transported by the East Auckland Current. This has resulted in the proliferation of one particularly unwelcome subtropical creature, a sea urchin known as Centrostephanus rodgersii.
The urchin is an indiscriminate feeder with a devastating track record. When it arrived in the warming waters of Tasmania, Australia, it ate away at the region’s kelp forests, ultimately contributing to their destruction and, subsequently, the destruction of the region’s lobster fishery. At the Poor Knights, a similar trend is underway. Since monitoring began in 1999, the urchin population has grown tenfold, and the recent accumulation of barrens — lifeless patches of reef created after the urchins consume marine life — indicate that they are eating everything in sight. At scale, this would have a catastrophic effect on the marine ecosystem, as well as the tourism and recreational economy it supports.
Monique Ladds, a Marine Technical Advisor at the New Zealand Department of Conservation (DOC), has been monitoring Centrostephanus rodgersii for years and helps understand the impacts of the urchin’s spread in the Poor Knights. High-quality data is essential to Ladds’ work and she is always on the lookout for new observational sources. Direct observations of temperature at and below the surface are particularly valuable, as they enable Ladds and her peers to pinpoint the specific conditions under which the urchins flourish and to predict long-term impacts of warming in the region.
According to Ladds, the typical process for making direct observations in the Poor Knights is cumbersome, albeit familiar to ocean scientists. To collect temperature data, for example, researchers travel for miles by boat and deploy a data logger. Then, at some point in the future, the researcher repeats the boat trip, retrieves the device, takes it ashore, and — finally — views the data, which is not accessible remotely. This all assuming, of course, that the data logger survives deployment.
“They [the loggers] fail all the time,” said Ladds. “You have to download the data, you have to clean all the data. You have to do all the annoying stuff that goes with it.”
Limited access to direct observations means that Ladds and her peers rely on satellite data and other indirect observations. This data is useful, but gaps persist.
“[The data] It’s poor — that’s the easiest way to say it,” said Ladds. “We recently explored how to rectify historical changes in even just sea surface temperature, and that's been really difficult because, in New Zealand, marine reserves are really, really small.”
“We really struggle to get that fine-scale information that we need,” added Ladds.
In late 2022, Dr. Robert Smith of the University of Otago, and DOC Marine Reserve Ranger Evan Davies, deployed a Sofar Spotter Platform at the Poor Knights. The durable platform, acquired via the Aqualink program, includes a Spotter buoy and Smart Mooring, and makes real-time observations of wave spectra, surface and subsurface temperature, barometric pressure, and other variables. It transmits data in real-time via satellite and all observations are remotely accessible via the Spotter Dashboard and API.
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The availability of real-time temperature data will directly support Centrostephanus rodgersii monitoring. At any moment, a researcher will be able to open their laptop and view real-time conditions at the Spotter deployment location or access historical time series data. This information could be cross referenced with divers’ observations of urchin habitats, or used to predict where urchins might proliferate in the future.
Smith predicts that the data collected by Spotter will also help DOC, the scientific community, and mana whenua better understand the causes and impacts of extreme weather events in the Poor Knights. This includes marine heatwaves, one of Smith’s primary research areas, which have become a common occurrence in the region. During one such heatwave in early 2024, Spotter recorded a max subsurface temperature (at 20m depth) in the islands of 22 degrees Celsius. This real-time data, which was unavailable prior to the deployment of the Spotter, indicated that the subsurface temperature had eclipsed the region’s coral bleaching threshold, a critical warning sign for reef conservationists.
For Davies, who frequently visits the Poor Knights as part of his rangering duties, access to real-time wave and wind data, specifically, is extremely valuable to his work planning. Using these observations, he can ensure that conditions are safe enough near the islands before he embarks on a long boat trip. Coastal communities and visitors that dive, fish, and boat in the islands benefit in the same way.
“Doing a big trip like that, it's a lot of planning and it's a lot of work, even though they're done on a regular basis,” said Ladds. “We can log on and check the wind and the waves and go, ‘OK, it's looking really nice out at the Knights. Today's a good day to head out.’”
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The deployment of a Spotter Platform in the Poor Knights has already caught the attention of rangers working in other marine reserves across New Zealand. They, like Davies, understand how access to real-time ocean data can bolster operational safety and efficiency, while also supporting research, conservation, and recreational activity. “They all want one!” said Ladds.
Existing regional systems of Spotters in Florida, North Carolina, and the Dominican Republic, offer a blueprint for potential wide-scale deployments across New Zealand’s marine reserves in the future. Spotter is flexible, easy to use, and rapidly deployable, which simplifies the process of creating a network of multiple devices. These networks increase the spatial density of observations collected and enable more dynamic modeling of data.
Ultimately, future Spotter deployments in the Poor Knights or other New Zealand marine reserves will be collaborative decisions made by Indigenous coastal communities, government, and academic partners. Together, these groups continue to monitor, protect, and raise awareness around the country’s changing marine ecosystem.
“People are understanding the problem now,” said Ladds. “How do we actually manage this properly? It’s through ecosystem management and fisheries management.”
To learn more about the Spotter Platform, please contact our Sales team.
