THE EFFECT OF ENVIRONMENT ON MARINE NEMATODE ASSEMBLAGES AS INDICATEDBY THE MATURITY INDEX

The nematode Maturity Index (MI) has been proposed as a means of detec ting disturbance in marine and terrestrial biotopes. However, few stud ies have dealt with the effect of the environment on MI. Using data ta ken from an extensive study of a polluted estuary, a number of variabl es were investigated to determine their effect on the MI. Sediment med ian particle diameter, nematode population density and the heavy metal elements analysed had no effect on values of the MI. However, number of species present in a sample, distance from pollution source and pro portion of different nematode feeding groups, especially feeding group s 1B and 2A, had significant effects on values of the MI. The Maturity Index was found to be a robust index and in general agreement with va lues derived from traditional indices.