Marine mammals inventory

The aim of this action is to fill essential gaps in the knowledge about marine mammal species of European Community interest in the Baltic Sea (Harbour porpoise, Grey seal and Ringed seal), enabling Estonia, Latvia and Lithuania to fulfil the requirements for their protection under the Habitats Directive.
Dealing with very mobile animals migrating through the whole Baltic Sea and beyond, this action aims at evaluating the role of the project areas in the life cycles of these species (e.g. resting, breeding, foraging and migrating) and identifying the most important areas for these marine mammals.

Marine mammals inventory involves three different methods to be performed in Estonia, Latvia and Lithuania and additionally gathering of available information on marine mammals in Russian waters (Gulf of Finland) of the Baltic Sea.

Inventory of Harbour porpoise (Phocaena phocaena)
For detecting Harbour porpoise and measuring its activity passive submerged porpoise detectors (T-PODs) are used. These computerized acoustic devices monitor the environment for porpoise sounds and record them thus allowing registering presence or bypass of these otherwise “invisible” animals.
The project inventory will cover the whole length of the Eastern Baltic Sea coast from Lithuania to the Gulf of Finland. Arrays of T-PODs will be deployed in pre-selected places (6 T-PODs in each Baltic country). In 2 seasons (2007, 2008) different pre-selected areas are used, so different project areas will be covered. These detectors will be physically placed in the sea and every three months the data from T-PODs will be downloaded and batteries exchanged.

Grey seal (Halichoerus grypus) survey
For the Grey seal survey the GPS-GSM tags (position from GPS, data transfer via GSM) will be used that allow tracking these diving animals and study their activities in time and space. The Grey seals will be caught by net in the Gulf of Riga after their annual moult (early June 2007) and the equipment will be glued on their head or back. It will work up to next moult, i.e. 11 months. The optimal number of marked seals is 10 to be able to draw conclusions and detect general patterns. It was decided to mark seal females as this enables to get information about breeding places. However the results of female tracing will allow to identify and estimate the concentrations of the whole Grey seal population, since males are following the females.

Ringed seal (Phoca hispida) survey
The method, which is worked out and implemented in the Baltic region since the mid-1980-ies will be used to identify the concentrations of the Ringed seal.
The ice covered areas of the Gulf of Finland and the Gulf of Riga will be observed by aerial transect survey flights, mapping abundance and distribution of the Ringed seal. These flights are carried out in mid-April, over 2 project years. In addition, the 3EST Väinameri project site will be covered by observation flights.
BEF Life Natura