A NIWA marine ecologist has returned from Antarctica after leading the first of two trips to study Weddell seals and investigate whether the newly-created Ross Sea Marine Protected area is effective in conserving the species.
During their first (now completed trip) at the start of November, Dr Kimberly Goetz and three other scientists equipped up to 21 Weddell seals with different devices to learn more about their environment and behaviour while they look for food.
The team anesthetised the mammals then attached jaw accelerometers, GPS, time-depth recorders and cameras to determine when and what the seals are eating, how deep they go to forage their food and how successful they are at catching their prey.
"We can create these animations that shows the animals going into the ice hole and then going down and how they're moving 3D and then coming back up to the same ice hole and then exactly when they're capturing prey," Dr Goetz said.
She said people are captivated by seeing the seals looking back at the researchers in the vision from their perspective, as well as the seals' interacting with each other.
The unique vision also captures playful interactions, mums surfacing to check on pups and courtship behaviour.
"The cameras are facing that way so we miss some of the other parts so we hopefully see some definitive things that look like there's mating going on so it’s the first time that’s ever been documented.
Dr Goetz said while the mission was a success, working in an extreme environment with devices that had never been used together to research Weddell seals had its challenges.
"We’re talking using devices that have a battery and so batteries never last as long in the cold as you want them to… so we ended up wrapping some of our tags in neoprene like little wetsuits literally to make the battery life last longer.
"We started tagging mums with pups that were a couple of weeks old and apparently they don’t really leave their pups much when they’re that young so that’s when we’re getting a lot of this mum pup interaction… We’re like, ‘No, go forage!"
Dr Goetz said it took a while to figure out when the mum’s would start hunting but they figured out over time it was once the pups were 25 to 30 days old.
The second trip will be in February where Dr Goetz will join scientists from overseas to deploy Conductivity-Temperature-Depth Satellite-Relay Data Loggers (CTD-SRDLs) on the seals to determine their long-term over-winter movements, collect oceanographic data, and examine where these animals travel within the boundaries of the Ross Sea Marine Protected Area.
They will also be looking at early pregnancy in Weddell seals, using ultrasound technology to determine if each of the tagged seals are pregnant.
Pregnant females that fail to pup the following spring, suggests they were not able to find enough food to support their developing foetus.
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