For some years, the beaches of Ivory Coast have become more and more polluted by hydrocarbon residues. In addition, plankton net hauls have shown that the quantities of hydrocarbons in suspension in sea water are far from being negligible and generally more important in shallow water near the coast. The presence of oil in the stomachs of pelagic fish and the scarcity of eggs and larvae of these fish suggest the hypothesis that the decrease in the yield of these fish in Ivory Coast waters may at least partially be due to this oil. The authors suggest that strong action should be taken in order to force oil tankers to respect international rules concerning tank cleaning (at a minimum distance of 100 miles offshore) until better cleaning methods are employed.