Long-term population trends of the benthic macrofauna in the offshore mud of the Northumberland coast

Abstract

The changes in the number of species, the number of individuals and the production of a benthic mud association have been studied for a 4-year period. The numbers of species and the total estimated production appear to have remained substantially stable, but the number of individuals has more than doubled over the period. When considering the high ranking producers, it is clear that not all of these have contributed to the general rise in numbers of individuals. Two species, Ammotrypane aulogaster and Abra nitida have shown an abrupt fall in population numbers and biomass. At the beginning of the investigation in 1971, these species figured importantly in the production estimates with 20 and 6% respectively of the total production. After 1971, both were effectively eliminated from the production of the association.