Shallow marine bays teem with life
Shallow marine bays are defined as sea areas less than four metres in depth, which are almost surrounded by the mainland. Such bays are diverse in terms of size, openness, water currents, and salinity. Of the habitats listed in the EU Habitats Directive, large shallow marine bays, coastal lagoons, and estuaries are all represented on the spectrum of shallow bays.
Vascular plants
Aquatic vascular plants include those that sprout both underwater and above the surface. These include, for example, lake reeds, water horsetail, yellow water-lily, fennel and perfoliate pondweeds, as well as brackish-water crowfoot.
Birds
Dabbling waterfowl, such as the mallard duck and the mute swan, thrive in shallow bays. These areas are also home to insect-eating birds, such as warblers, as well as wading birds, which include the oyster-catcher.
Fishes
Perch, pike, roach, and bream are just some of the fish species that thrive in shallow bays. Such areas are also important spawning grounds for many fish species.
Particular attention is paid to the lagoons or flads, which are almost entirely cut off from the sea. Lagoons are protected by the Finnish Water Act.
Shallow marine bays have a diverse biota
The shallow marine bays deserve similar special attention. These sheltered bays are often surrounded by reed beds and are teeming with life, providing ecosystem services over a wide area, both on land and at sea.
Surface run-off waters carry both suspended solids and nutrients to the shore, much of which binds to either the shoreline sediments or aquatic vegetation. The flora is abundant and diverse and a large variety of invertebrate animals and insect larvae scurry about in the protection of its vegetation.
Some fish species, particularly pike, perch and roach, enter such shallow habitats to spawn, and their fish larvae begin their lives in these sheltered and gentle conditions. Larger fish, as well as water birds and waders, gather in such habitats to feed on the abundant fish juveniles and benthic invertebrates.
Many insects lay their eggs in the warm, calm waters of shallow marine bays, and the larval stages develop either within the bottom sediments or among the vegetation.
Shallow marine bays are important areas for spring-spawning fish species such as perch.
Endangered aquatic plants thrive in shallow marine bays
Most of the endangered aquatic plants of the Finnish coastline can be found in shallow coastal waters. The Nature Conservation Act prohibits any destruction and damage to their habitats. By protecting the unspoiled marine bays of special natural value, a wide range of biodiversity and ecosystem services can also be preserved effectively.
Aquatic plants thrive in well-lit, shallow bays.