DYNAMICS OF DEVELOPMENTAL STABILITY OF SEALS AND POLLUTION IN THE BALTIC SEA

Fluctuating asymmetry of skull characters, as a measure of development al stability, was studied in two seal species: grey seal Halichoerus g rypus (Fabricius, 1791), and ringed seal Pusa hispida Schreber, 1775 f rom the Baltic Sea. Seals were collected in three different periods of water pollution of the Baltic Sea. We revealed the same temporal dyna mics of fluctuating asymmetry level for both species: it proved to be low in ''pre-pollution period'' (years 1877-1936), high for the ''high -pollution period'' (1964-1975), and was again low for the ''low-pollu tion period'' (1986-1990). These data suggest that changes in the cond ition of the seal populations in the Baltic Sea revealed by changes in developmental stability are correlated with the dynamics of the pollu tion level.