AN ASSESSMENT OF THE IMMEDIATE EFFECT OF THE BRAER OIL-SPILL ON THE GROWTH OF HERRING LARVAE USING OTOLITH MICROSTRUCTURE ANALYSIS

Herring larvae were sampled around the Shetland Isles as part of an en vironmental monitoring programme in the immediate aftermath of the wre ck of the oil tanker Braer on 5 January 1993. Otolith microstructure a nalysis was used to investigate the short term effect of the oil pollu tion on the growth rate of the larvae. The results failed to detect an y differences in growth between larvae sampled at stations heavily aff ected by oil and those outside the affected area. Otolith growth was a lso very similar before and after the spill, and to growth rates measu red in January 1990 in the same area. However, the oil concentrations to which the larvae were exposed exceeded the threshold concentration for sublethal effects on larval fish in laboratory experiments. Longer term effects cannot therefore be ruled out.