Distribution, abundance and some population characteristics of the ocean quahog, Arctica islandica (Linnaeus, 1767), in the Mecklenburg Bight (Baltic Sea)

In the Mecklenburg Bight (western Baltic Sea), the ocean quahog, Arctica islandica, constitutes the most important species below the halocline. In 1999 a benthos survey at 95 stations in the Mecklenburg Bight showed a wide distribution of A. islandica at depths between 15.6 and 29.6 m. Mean abundance at these depths was 91 ind./m super(2) with a biomass (AFDW) of 15 g/m super(2). Maximum densities observed at these depths were 571 ind/m super(2) and 120 g/m super(2), respectively. The Mecklenburg Bight had an estimated colonized area of 5200 km super(2) and a total annual production of 26500 t AFDW. In comparison to a data set of the 1960's, we found an increased quahog population. Ocean quahogs ranged from 1.5 to 64 mm in shell length and from 1 to 70 years of age. Growth was relatively slow for the first 40 years. Most (90%) individuals in the population measured