Cross Tay Link Road

Practecology undertook freshwater pearl mussel surveys in the main stem of the River Tay under the footprint of the proposed Cross Tay Link Road.

The Freshwater Pearl Mussel

The freshwater pearl mussel is a critically endangered mollusc inhabiting our freshwater rivers and streams. It is fully protected under Schedule 5 of the Wildlife and Countryside Act 1981 (as amended) and listed on Annex II and V of the Habitats Directive 1992 (as amended). It has a remarkable life history which may in part be responsible for its population decline although in some instances animals can live as long as 100 years. 


  • An old freshwater pearl mussel shell on the river bed

    An old freshwater pearl mussel shell on the river bed

  • Suitable substrate for freshwater pearl mussels

    Suitable substrate for freshwater pearl mussels

  • A freshwater pearl mussel

    A freshwater pearl mussel

  • An unsuitable substrate for freshwater pearl mussels

    An unsuitable substrate for freshwater pearl mussels

Freshwater pearl mussel surveys

Due to its protected status, surveys to determine the presence of freshwater pearl mussels can only be carried out under a licence issued by Scottish Natural Heritage (SNH). Practecology holds a licence for freshwater pearl mussel surveys.

To inform the Cross Tay Link Road, Practecology carried out surveys under the footprint of the proposed scheme. These were carried out by experienced staff working in the river using bathyscopes. In deeper water and/or faster currents staff used dry suits and snorkelling equipment so that the river bed could be observed as closely as possible. 

Useful Links

See the link https://www.nature.scot/plants... to find out more about this animals biology or visit https://www.pearlsinperil.scot... to understand the efforts underway to conserve it.