Seals and harbour porpoise grow rapidly during their first year of life. And their weight varies greatly between summer and winter. During the winter, they build up a large stock of lard to keep warm. It allows them to swim around in ice cold water.
Through monthly measurements of the length and body size of harbour porpoise and seals, we can examine their growth and seasonal body shape in detail. This is done both with physical measurements during the training, but also with photography of the animals from different angles. By comparing photographs with physical measurements, we can develop methods to measure the animals’ body shape and size in the open air through drone images.
Thereby we can examine the growth of the animals and so-called BMI (which is also used to assess body shape in humans) to understand the age distribution and health status of the wild harbour porpoise and seals.