The systematic collection of scientific data that enables a wildlife impact assessment is an essential part of an oiled wildlife response. An oil spill in or near areas where marine wildlife is concentrated is likely to affect a considerable number of animals. Thus it is important to be able to tell how many animals, and/or what proportion of a population may have been killed by the pollution.
But a reliable scientific assessment can only be made if the right data have been systematically collected from the very beginning of an event. Methodical and frequent monitoring of beaches and other parts of the coast line to look for carcasses and/or live animals that have washed ashore must be carried out.
In addition, at sea experiments are needed to estimate the proportion of impacted animals that die at sea and therefore will not be collected on a beach. For example, drift block experiments can be used to mimic the behaviour of such carcasses, increasing teh accuracy of the estimates. Drift block studies done pre-spill are also used to predict where oiled birds might end up, allowing for more effective response to live birds.
A wildlife impact assessment should also include a scientific analysis of carcasses that have been collected to determine which died as a result of the spill and which may have been oiled post mortem. Total numbers, numbers per species, age distribution per species and, if possible, biometric analysis to determine proportional impact on geographic subpopulations are all important data that can be produced if activities are carried out according to standard protocols.