Researchers are delving into the mystery of how grey seal pups on Sable Island develop the ability to survive their first year. Despite the challenging odds, with up to around 400,000 grey seals congregating on the small sandbar approximately 300 kilometers southeast of Halifax each winter for mating and pup birthing, the young pups face a tough journey.
The pups receive short-term maternal care, with mothers nursing them for only two to three weeks before leaving them to fend for themselves without swimming, diving, or hunting guidance. Marine biologist Michelle Shero from the Woods Hole Oceanographic Institution in Massachusetts describes the situation as remarkable, emphasizing the independence these pups must quickly acquire.
Regrettably, an estimated 90% of grey seal pups on Sable Island do not survive their first year, likely due to the high population density and intense competition for limited food resources. This lack of survival is evident early on as the young seals struggle with diving and foraging compared to the adult seals.
Shero initiated a pilot project utilizing Fitbit-style monitors to monitor the health and progress of the baby seals. These monitors, similar to those used by humans for tracking steps, heart rates, and sleep patterns, collect data on the seals’ heart rates, intervals between heartbeats, and even conduct full EKG readings. Equipped with accelerometers, the monitors also track the movement of the pups, providing insights into their rest and activity levels.
The project aims to understand how the seals utilize their energy, monitor their health and development post-weaning, and prepare them for ocean life. The pilot project initially focused on six pups up to a month old before they started swimming, emphasizing the need for the pups to learn breath-holding, efficient oxygen usage, and slowing their heart rate for extended dives.
Shifting to the development of the monitoring technology, engineer Ben Weiss from Woods Hole Oceanographic Institution rose to the challenge of creating a durable monitor for the seals. The monitors, attached via a tiny 3D-printed backpack and electrode holders, are designed to be minimally invasive for the seals while being practical for field researchers.
The heart monitors, which can last up to nine days, are non-intrusive and provide valuable data on the seals’ activity levels, heart rates, and energy expenditure. This advancement in monitoring technology represents a significant improvement from previous models, eliminating the need for surgical implantation or real-time monitoring by researchers.
Shero highlights the broad applicability of this technology to various species and expresses plans to expand the project by outfitting more pups and their mothers with the monitors. This expansion will enable researchers to gain insights into the mothers’ investment in their pups and how effectively the pups utilize the energy provided to them.
