A number of methods were applied to assess disturbance in macrozoobent
hic communities in three Mediterranean lagoons with different levels o
f stress. Tsopeli, Ionian Sea, with no obvious source of stress, harbo
urs a fauna typical of brackish-water lagoons. Vivari, Aegean Sea, als
o without apparent source of disturbance, is characterised by a few ty
pical lagoonal species and some species characteristic of perturbation
. Gore lagoon, in the northern Adriatic, is much larger and more open
to the sea. At the centre of the lagoon, where anoxia is known to occu
r in the summer (''Goro polluted''), the fauna is dominated by species
typical of disturbance and a few lagoonal species. A dredged area clo
ser to the sea (''Goro dredged'') is totally dominated by species char
acteristic of disturbance. The species diversity in all lagoons ranges
from low to very low. According to the distribution of individuals in
geometric abundance classes, all the lagoons are characterised as str
essed. The distribution of individuals in geometric size classes shows
dominance of larger specimens in the least disturbed Tsopeli and excl
usively small sizes in the greatly disturbed dredged area of Gore. The
abundance/biomass comparison curves characterise Tsopeli as undisturb
ed, Vivari and Gore polluted stations as moderately disturbed and Gore
dredged station as disturbed. The last two methods agree with the cha
racterisation derived by examining the dominant species. It is conclud
ed that methods based on size changes of the fauna are more sensitive
than those based on relative abundance in assessing disturbance in coa
stal brackish-water lagoons.