The number of seals at ports born in the Coster Sea has increased by more than half since 2012. To understand why, researchers at the University of Gothenburg are currently using drones and AI to track puppies' childhoods.
When the population of port seals on the West Coast collapsed in the mid-20th century, it was primarily due to excessive hunting and was approved by prize money. When hunting was banned, the population gradually recovered, and today's port seals can be seen again in many places along the West Coast. However, new threats are emerging to Seal. Preliminary results from the University of Gothenburg show that concentrated fishing by large industrial trawlers from many countries has disrupted cod and herring stocks, leading to harbor seals sealing against other less nutritious fish species. Researchers suspect seals could spend more and more time searching for foods that affect both growth and reproduction.
In Coster Hubbet National Park, researchers at the University of Gothenburg are paying attention to the decline in the number of seals in the port being collected.
Decreasing trend
“The trend is declining year by year. In 2012, around 400 seal puppies were born on Skelly and the island in the national park. Last year we counted 170 puppies.”
Previously, researchers had to be content with seals from afar, but with the help of modern technology, they could conduct more detailed research that could provide new ways to monitor seals. By photographing a sticker colony with a drone in June, when female seals give birth to this year's puppy and return at the end of August, researchers can assess the puppy's growth at a population level.
Seal researchers at the University of Gothenburg launch a drone from Ulschormann, south of Coster Havette National Park, and fly towards Seal Harleout.
Photo: Karinhårding
“We take photos from high altitudes to avoid disturbing seals. With the help of AI, we can estimate the size and weight of a puppy with just 3 kg error margins. Die out sites,” says Dia Carroll.
Developed by Slottsskogen
The AI model used was developed by researchers in collaboration with Slottsskogen Zoo. When the harbor seals were born in the seal pond, the true growth of the puppy was linked to images taken by a drone above the pond. Additionally, harbor seals have a unique pattern in fur that allows individuals to distinguish. AI models are also trained to do this.
“It is difficult to assess the physical condition of a seal with binoculars from a bobbing boat. Therefore, we were able to rely on a previous investigation of dead seals in Stockholm to see growth and health issues, but about 20 seals a year.
Since drone research began in 2021, researchers have been able to follow the development of seal populations. It appears that only women who accumulate a significant amount of fatty deposits give birth to puppies every year. Lean seals only have puppies every other year, a natural way to slow population growth when food is scarce. Female seals depend on their survival and are waiting for their environment to improve.
People contribute
“Women are the most important individuals for colonial survival. Women who are well-suited have puppies each year, but they are steadily less. Let's see if the positive trend can be reversed this year.
Methods for monitoring seals with drones and AI have spread to other research groups. SLU is currently running a similar project at Harbor Seals in Hallands Väderö, where researchers in Estonia are investigating how gray seals are affected by the decline in sea ice over recent decades. They are more crowded without ice and have a negative effect on the puppy's growth.
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Daire Carroll, Biträdande Forskare, Biologue, Universitette.
Photo: privat
Thanks to AI models, researchers can also use photographs of stickers taken by individuals. Last year, Darie Carroll received over 800 photos from the public on the Sälfie-ID project.
“Send photos. Thanks to the AI model, you can identify many of the stickers in the photo at individual levels. Thanks to the Sälfie-ID project, you can understand how the stickers work and how they move along the entire coastline,” says Daire Carroll.
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