German Federal Agency for Nature Conservation (BfN)


Selecting Sites for Species Protection: Annex II of the Habitats Directive

The EU Commission finalised the criteria for site selection for the species listed in Annex II of the Habitats Directive at a biogeographic seminar and in conjunction with the Habitats Committee Scientific Working Group. The criteria require that proposed sites contain the key partial habitats to accommodate both the annual patterns and lifecycles of the listed species.


While all freshwater fish species are migratory fish to some extent, their migration ranges vary from species to species.

The fish listed in Annex II can be separated into the following categories of migratory species:

  • Spawning migration (e.g. the European river lamprey (Lampetra fluviatilis) travels from its marine feeding grounds to river estuaries and then further upstream to higher-level gravel beds for spawning)
  • Larval and juvenile migration (e.g. larval and juvenile twaite shads (Alosa fallax) travel downstream following their prey organisms)
  • Food-related migration (e.g. young salmon (Salmo salar) migrate downstream towards the sea to reach their feeding habitats)
  • Winter migration (e.g. blageon (Leuciscus souffia) move to deep river zones in winter and then back to shallower streams in spring)
  • Drift correction migration (e.g. adult bullheads (Cottus gobio) drift with the downstream current then travel upstream to return to their original sites)

Migration periods in larger rivers can involve a number of days, weeks or months. Suitable sites must thus be selected for these periods to take in the mouths of smaller auxiliary streams, blind arms and safe havens in shallow waters behind river islets. Depending on the species involved, harbour basins may also be considered for site selection. Resting areas need a minimum range of between two and three kilometres downstream for drift correction. The distance between the resting areas should not exceed 10 to 20 kilometres (relative to the needs of the species in question).

Site selection must take in species’ habitat-related needs to ensure their survival. This includes areas in which the species remain for longer periods. Site designation is not necessary for areas through which the fish pass relatively quickly (from A to B in a matter of days).

Partial habitats to be taken into account when selecting sites include:

  • Spawning grounds
  • Egg-laying sites (if not identical to spawning grounds – as is the case with Alosa fallax, for example)
  • Larval habitats
  • Habitats of juvenile animals
  • Feeding habitats
  • Winter quarters
  • Resting grounds (involving long-distance migration of adult animals upstream and juvenile animals downstream)

The approach described above should be seen as the minimum requirements under the Directive. The member states are encouraged to consider including entire river systems in their proposals.


In some cases, it may be necessary to designate as components of areas of Community interest any buildings and other anthropogenic structures that serve as the only known habitat.

Last Change: 25/03/2021