Large shallow inlets and bays

Compiled by Dieter Boedeker, Germany

 

1. European Unions Natural Marine Habitat types definitions: 1160 Large shallow inlets and bays

PAL.CLASS.: 12

1.1. Description of the habitat

Large indentations of the coast where, in contrast to estuaries, the influence of freshwater is generally limited. These shallow (*)indentations are generally sheltered from wave action and contain a great diversity of sediments and substrates with a well developed zonation of benthic communities. These communities have generally a high biodiversity. The limit of shallow water is sometimes defined by the distribution of the Zosteretea and Potametea associations. Several physiographic types may be included under this category providing the water is shallow over a major part of the area: embayments, fjards, rias and voes.

1.2. Characteristic species

Plants: Zostera spp., Ruppia maritima, Potamogeton spp. (e.g. P. pectinatus, P. praelongus), benthic algae.

Animals: Benthic invertebrate communities.

1.3. Corresponding categories

German classification: "B31 naturnaher Boddengewässerkomplex", "B32 Boddengewässerkomplex, geringe Belastung".

1.4. Reference

European Commission (2007). Guidelines for the establishment of the Natura 2000 network in the marine environment. Application of the Habitats and Birds Directives. Appendix I: Marine Habitat types definitions. Update of “Interpretation Manual of European Union Habitats” (EU interpretation manual).

Luther, H. (1951). Verbreitung und Ökologie der höheren Wasserpflanzen im Brackwasser der Ekenäs-Gegend in Süd-Finnland. I. Allgemeiner Teil. ABF 49, 1-232. II Spezieller Teill. ABF 50, 1- 370.

(*) National experts consider inappropriate to fix a maximum water depth, since the term 'shallow' may have different ecological interpretations according to the physiographic type considered and geographical location.

 

2. Additional HELCOM information

2.1 Description of the habitat

Baltic large shallow inlets and bays are coastal features such as fjords and/or fjord like bays, shallow bights, but also specific subtypes of Bodden. The characteristic physiographic and biological features are more similar to the adjacent open Baltic Sea than it is, for example, the case in lagoons or estuaries.

2.2 Distribution

Large shallow inlets and bays occur in all HELCOM sub-regions of the Baltic Sea area.

2.3 Importance (sub-regional, Baltic-wide, global)

Large shallow inlets and bays are of Baltic-wide importance. Some of them, e.g. the Bodden of the southern Baltic Sea coast, are of global importance. The physiographic features of sheltered bays provide imortant habitats for birds, fish, aquatic and coastal plants and animals (birds, fish, invertebrates). The benthic flora is often rich and may include threatened and/or declining plants such as seagrass beds. In some cases the benthic and halophytic vegetation (mainly along the shores) may cover large parts of the seafloor of the bay. The plant vegetation provides habitat for many aquatic invertebrates and these are suitable food for larger animals such as fish or birds.

2.4 Status of threat/decline

Human activities have caused various pressures in many large shallow inlets and bays which in some cases resulted in severe damages. Also, the length of pristine shores in a natural or near natural state is low and steadily decreasing. The habitat type is under threat or decline along many central and southern Baltic Sea coasts. According to the HELCOM Red List of Biotopes and Biotope Complexes (HELCOM, 1998) the Baltic wide threat category for fjords and fjord like bays is "Endangered" (Bodden are "Heavily endangered"). This is mainly due to decreased quality, rather than loss of area. Regeneration is considered difficult.

2.5 Threat/decline factors

Eutrophication and pollution by drainage from agriculture and forestry and other sources (like traffic and industry) are serious threats and factors for deterioration. They cause often oxygen deficiency in deep water. Furthermore, humans also use this habitat type for other activities such as fishing, offshore constructions, extractions, dredging, dumping of dredged material, tourism and recreation which all may cause visual, acoustic or physical disturbance to wildlife and the habitat.

2.6 Options for improvement

Programs and measures for a drastic reduction of the eutrophication and pollution are needed. Additional protective measures could be: preservation of natural dynamics (HELCOM Rec. 16/3), restriction of building activities along the shores (HELCOM Rec. 15/1), restrictions for offshore constructions, introduction of ecologically sound fishing and farming methods as well as regulations for ship traffic, boating, unregulated growth of tourism and harmful recreational activities. As for all natural habitat types, an inventory and a monitoring and assessment programme (also for human activities) is obligatory for EU Member States. They are further obliged to take all appropriate steps to avoid further deterioration. This includes the obligation to protect this natural habitat type within the Natura 2000 network, and thus to designate as many SACs as necessary to guarantee its favourable conservation status. Member States have to follow Article 6 (3) of the Habitats Directive: Plans and projects which are not directly connected with or necessary to the management of a Natura 2000 site but likely to have a significant effect thereon, either individually or in combination with other plans or projects, shall be subject to appropriate assessment of its implications.

2.7 References

HELCOM (1998). Red List of Marine and Coastal Biotopes and Biotope Complexes of the Baltic Sea, Belt Sea and Kattegat - Including a comprehensive description and classification system for all Baltic Marine and Coastal Biotopes. HELCOM-Baltic Sea Environment Proceedings 75, Helsinki Commission. 115 pp.

Munsterhjelm, R. (1997). The aquatic macrophyte vegetation of flads and gloes, S coast of Finland. Acta Botanica Fennica 157: 1-68.

Nordiska Ministerrådet (2001). Kustbiotoper i Norden: hotade och representativa biotoper.  TemaNord 2001:536.  ISBN 92-893-0626-2.  pp.  345. (in Swedish).