Pontoporeia femorata (Kroyer 1842) (Crustacea)

Compiled by: Fritz Gosselck, Germany

1. Description / Ecological demands / Autecology

P. femorata is an amphipod species of marine arctic origin. It is restricted to the deep cold water zones in the Baltic Sea and tolerates reduced salinities down to 6 psu. P. femorata is a deposit feeder, which feeds mainly on settled phytoplankton and other detrital organic matter. The amphipod is found deeper in the sediment than M. affinis. It is an active bioturbator thus influencing the sediment structure, nutrient fluxes and oxygen availability in the sediment. Dense populations are up to 2.000 ind./m² (Askö area).

2. Distribution

P.  femorata is distributed over the Baltic Sea up to the Aland Islands, including the Belt Sea.

3. Importance

P.  femorata is an endemic species to the Baltic Sea.

4. Status of threat

P.  femorata is red-listed in the German part of the Baltic Sea as “vulnerable”.

5. Threat factors

The loss of oxygen in the Baltic Sea bottoms has reduced the abundance of M. affinis. Reduction of nutrient loading improves its situation.