Assessing the effects of the oil and soya spills resulting from the OLIVA incident at Nightingale on the lobster fisheries at the Tristan group of islands is difficult for a number of reasons: 1. the quantification of the impact of the oil spill on settlement and juvenile mortality is not straightforward, both at Nightingale and at Inaccessible islands to which the oil spread; 2. the soya spill, which is restricted to Nightingale island, has certainly had an impact there as evidenced by the poor catch rates experienced for recent experimental catches; however this would have been caused by either or both of a short term migration of the lobsters from the fishing area1 and an immediate additional mortality on adult lobsters; the quantification of these effects is again difficult, and importantly the consequences of the two possibilities are rather different; 3. there are two alternative models for the growth rate of lobsters at Nightingale island, and results do change appreciably depending upon which of these better approximates reality.