Birds, Grey Seals and Marine Life

The brackish environment of Saint Anna & Gryt, with its mosaic of different habitats, is home to a very interesting fauna. Thirty-five coastal birds species breed here, and the population of Grey seals is steadily growing. A mix of saltwater, freshwater and migrating fish species live in the sea.

Grey seal bobbing its head above the water, the most common way of spotting them in Saint Anna.


There is an abundance of birds around the islands. The area is famous for its large number of White-tailed Eagles, and sighting them soaring high up in the sky is almost a given. They nest in sturdy trees that are hundreds of years old in the inner and middle parts of the archipelago, and cover vast areas while hunting for prey.

Grey Herons breed in colonies in tall trees in the inner archipelago and they too search for food far and wide all the way to the outer archipelago.

Most notably, no less than 35 typical coastal birds breed on the barren islands in the middle and outer archipelago! It’s a bird lover’s paradise, especially earlier in the summer before many migrate south.

You’ll find different types of ducks, geese, waders, auks and gulls. Some typical Baltic species are Velvet Scoters, Ruddy Turnstones and Razorbills, which breed in the protection of squawking colonies of gulls and terns. Spotting predatory birds like Ospreys, Great Cormorants and Arctic Skuas is a delight!

Grey seals

Grey seals are quite plentiful around Saint Anna & Gryt these days. They mainly stay in the very outer parts of the archipelago, but they go for long hunting expeditions way further in also. If you’re observant, you may spot them bobbing their head above the surface!

These are large and impressive animals – males weigh around 300 kilos and measure 3 meters, females are somewhat smaller. The cubs are born at the edge of the ice around February-March. Adult animals can dive down to 100 meters and stay under the surface for up to 20 minutes! They mainly hunt for herring, but also catch perch, whitefish, salmon and cod.

Grey seals grow old, up to 45 years. This makes them very sensitive to even very low levels of pollutants in their catch, as toxins build up in their fat layers over time. In the first half of the 20th century, Grey Seals were very plentiful in the region. However by the 1970s, the species almost became extinct due to pollutants and hunting. Following efforts to decrease toxins in the Baltic, as well as protecting the species, the population has recovered significantly.

There are a couple of seal sanctuaries far out to sea with year-round protection, and during bright early summer nights the islets are yet again filled with bobs of seals. The melancholy deep bellow of the large males can be heard from far away – invoking a magical, primeval feeling for those lucky enough to experience it.

Seal hunting in the past

Disclaimer that the hunting of seals may sound brutal and distasteful to our modern ears, but it’s nevertheless an important part of the history of the islands. It was likely seals who brought the first settlers to the islands in prehistoric times. The animals have been hunted since then up until the 1970s, when the species became protected.

During the first half of the 1900s the practice of hunting seals reached its peak, and the large “seal battles” near Harstena are still remembered through stories and photos. Hundreds of seals would gather on the same islet, and the hunting crew would quietly get close, then storm ashore and club tens of seals to death before the large flock had time to escape into the water.

All parts of the seals were utilised. The island dwellers appreciated the fat meat, and the skin was used for boots or bags. The blubber was rendered as far away from settlements as possible, as the stench was beyond repulsive, and used for lamp oil and lubricant.

Note: It’s well worth a visit to the museum, as well as the historic building for rendering blubber, at Harstena to learn more about the history of hunting and fishing in the area. Check out our Interactive Map.

Marine life

The Baltic Sea is brackish due to the narrow and shallow strait connecting it to the Atlantic (the same reason why there are no noticeable tides). This in conjunction with many freshwater rivers flowing into the sea results in low saline levels.

Compared to saltwater seas, relatively few species are specialised to survive in this brackish “neither nor” environment. The archipelagoes on the east coast of Sweden are a meeting place for the most perseverant species from both saltwater and fresh water. Around 80 species that are visible to the naked eye live in the waters around Saint Anna & Gryt.


The history of fish fauna in Sweden is relatively recent. A mere 12,000 years ago, the entire Scandinavian region was blanketed with ice. Today, the Baltic Sea is home to a diverse range of fish species. It hosts freshwater inhabitants like pike and perch, saltwater denizens such as herring, cod and turbot, and migratory species including salmon, trout and eel. Presumably, both freshwater and saltwater species have developed genetic adaptations allowing them to thrive in the brackish waters of the Baltic.

From surface to seabed

The shallow sea regions with their rocky bottoms are hubs for biodiversity. From the surface, green algae flourish, extending down to roughly half a meter. This gives way to expansive forests of bladder wrack, which thrive until about 4 meters deep. These forests provide refuge to numerous small aquatic creatures and fish, functioning as vital "nurseries" for their larger counterparts. As you paddle in calm, shallow areas, the water may be clear so that you can observe these vibrant forests directly from the surface.

Deeper still, a thick belt of blue mussels extends down to depths of 25 meters. Their proliferation in the Baltic is partly due to the absence of traditional predators like crabs and starfish, which find the brackish waters inhospitable. These mussels aren't just food sources for both birds and fish, but they also play an indispensable role in the ecosystem. They filter and purify the seawater, removing nitrogen and phosphorus. Incredibly, over the span of a year, Baltic mussels can filter the entire volume of the Baltic Sea!

In areas where the force of waves and currents isn't enough to displace sediments, soft bottoms of sand and mud form. These soft-bottomed environments are especially prevalent in shallow waters, typically found in sheltered locations like bays or narrow channels between islands. These habitats are invaluable to marine life. Not only do they offer a serene environment, but they also have warm waters where sunlight penetrates easily to the seabed. Here, you'll find lush growths of marine plants such as eelgrass and pondweed. These bottom vegetations serve as prime spawning grounds for various species, supporting the early life stages of herring, pike, perch, eel, and flatfish. Additionally, adult fish like trout and cod frequent these areas to feed.