Harbour seal
The harbor seal (Phoca vitulina) has a round, chubby head that distinguishes it from the other two seal species found in Sweden. It is mainly found along the west coast.
Gather in groups
Harbor seals hunt alone, but on land they are often seen in small groups. They seek out sheltered sandbanks and skerries where they lie down to rest. It is relatively common for harbor seals to swim into rivers and they do well in freshwater too.
Eats fish
Harbor seals in Swedish waters feed on around 30 different fish species such as herring and dab, and they can dive to a depth of a few hundred meters if necessary. They can hunt and catch fish even in the dark. They use their whiskers to sense pressure changes in the water caused by fish movements. An individual eats 3–5 kg of fish per day.
Racing to adulthood
The young are born in the summer. Because they lack the woolly fur that other seal species are born with, they can swim and dive straight away. The pup, as the young is called, nurses for a few weeks and is then left to fend for itself. However, it takes several years for a harbor seal to become sexually mature and fully grown.
Abandoned child?
Sometimes people find a lonely seal pup on the beach, but it's almost never actually abandoned. The female is usually nearby but doesn't approach as long as there are people around. That's why it's important to walk away and leave the pup alone.
Quick facts
Food: Mostly fish
Weight: Up to 100 kg, sometimes more for males
Height: Up to 160 cm
Mating season: July
Young: 1 young born in the summer
Lifespan: Up to 35 years
Harbor seals are affected by the state of the sea
Large fluctuations
Historically, harbor seals have been hunted extensively. At the end of the 19th century, bounties were issued on harbor seals and the number of seals decreased significantly. They have varied greatly in numbers in the 20th century.
Viable and threatened
The group of harbor seals found on the west coast is currently classified as viable according to the Swedish Red List. But their numbers have started to decline again and the seals have also become leaner. Scientists believe this is due to overfishing, which has led to a shortage of fatty fish. At the same time, the small group of harbor seals in the Baltic Sea has long been classified as endangered. Wildlife control to reduce damage to fisheries has been granted for decades, but since 2022 the Swedish Environmental Protection Agency can also grant license hunting if the seal population is large enough.
Harbor seals are monitored
There are still major challenges facing the seals' habitat. Marine ecosystems are being disrupted by factors such as overfishing, dead zones, environmental toxins, litter and microplastics. That's why the size and health of seal populations are monitored to detect changes and threats in time.
Seals help researchers
Harbor seals have unique identifying patterns, almost like fingerprints in their fur, and the seals in Slottskogen have helped scientists develop photo-identification methods with these patterns. The method is used to monitor the status and health of wild seals. The park's seals have also helped develop a method for estimating the weight of seals through photos. Scientists are collecting photos of Swedish seals to understand how they move in the ocean and how human behavior affects them.