Liminganlahti Bay wetland area

Liminka Bay, or Liminganlahti in Finnish, is one of the most important bird wetland areas in Europe. That’s why it has also been designated as a RAMSAR site. RAMSAR sites, which can be found all around the world, are designated wetland and water areas, which are especially important to birds, but also to other biodiversity of nature. Liminganlahti Bay got it’s RAMSAR designation in 2002 because it is one of the most important bird migration, resting, nesting and feeding areas in Finland. The shore areas of Liminganlahti Bay are also important habitats in many respects, representing for example primary succession forests of the land uplift areas, mudflats and coastal meadows, and that’s why Liminganlahti Bay was also designated as a Natura 2000 site (in Finnish http://paikkatieto.ymparisto.fi/natura/2018/tiivistelmat/FI1102200.pdf )

Five people watching birds with binoculars and a telescope.
Liminganlahti is very popular bird watching place. Photo by Lari Järvi.

The area used to be grazed by sheep and cows but that stopped in the 1960s and the extremely shallow shores and coastal meadows started to be overgrown by reeds Phragmites australis. This was bad news for many of the wetlands ground breeding birds which need open coastal meadows. Some of the endangered aquatic plant species, which are poor competitors to reeds and need open water areas for growth, were also beneficiaries to the grazing. To keep the bay shores more open, grazing is practiced in the area again.

A field excursion on the Liminganlahti meadow were cows are kept on summer time. Photo by Lari Järvi.

Liminganlahti Bay is not only valuable above surface and on the shores and coastal meadows. There are plenty of endangered aquatic species that call Liminganlahti Bay their home. For example, threatened and directive species Alisma wahlenbergii and Hippuris tetraphylla can be found around the shallow coastal waters of the bay. These species benefit from grazing to keep the reeds at bay since they can’t compete with overgrowth by themselves.

Liminganlahti Bay is also important for fish spawning. There used to be many fishermen fishing around the bay but with the land uplift of almost 9 mm per year, the bay has gotten so shallow and overgrown with vegetation that it is not as important as a fishing area anymore. At least perch, pikepearch and vendace spawn in the area in the spring, and many more species of fish larvae can be found in the bay.

A small Temmesjoki River reaches the Liminganlahti Bay at its eastern shore and discharges fresh water to this 15 km long and at the widest 10 km wide bay. Water in the bay is almost fresh and so the flora and fauna that exist there are adapted to either fresh or low salinity brackish water. Even the large freshwater mussel Anodonta anatina can be found here. The shores of the bay are very shallow, and so are the middle parts of the bay as well, but the mouth to the sea is little deeper. Shores are mostly silty and muddy and the middle of the bay is soft sediments. The visibility is often very poor because the winds stir the bottom sediments and resuspend fine clay and mud particles from the bottom to the water column.

Very soft bottom with tube-like formations on the surface.
Chironomidae larvae on muddy bottom. They have made their cases from the soft sediments. Photo by Lippi Vertio.

One of the most important results of the SEAmBOTH project was the Zonation analysis of the most valuable marine areas. Liminganlahti Bay was clearly identified as one of the gems of the SEAmBOTH area. Also United Nations recognized the area as one of the most ecologically significant in the Baltic Sea (EBSA), and nationally in Finland, Liminganlahti Bay was designated one of the EMMA – or ecologically most significant marine areas – areas around the Finnish coast.

Chara growing under water between rocks.
There are lots of different species on the area, example Chara sp. Photo by Lippi Vertio.

No matter how you look at this bay – from the air, from the shores or from under water, it is definitely one of the most valuable marine areas that can be found in the Finnish coast, and in the SEAmBOTH area.

You can visit Liminganlahti Bay and learn a lot about the area’s birds in the Visitor center’s exhibition. There are also bird observation towers where you can go see the scenery from an elevation since they are just about the only higher places in the extremely flat shores of the Ostrobothnia.

Essi Keskinen

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