studied. There are practical impediments to the long-term research and funding commitments required to investigate a five to ten-year period of recovery; however, information on long-term recovery of ecosystems is essential to any assessment of environmental damage by oil pollution.

Laboratory studies have also had serious shortcomings (), and one shortcoming is inherent in all laboratory ecological studies: the limitation of extrapolating laboratory experimental results to the real world of nature. The few species selected for study cannot be considered representative of the response of the whole community. Typically, more tolerant and hardy species are chosen because they "do well in the lab." Often tests are made only on adults, although it is generally the larval and juvenile forms that are most sensitive. Many bioassay studies have lacked statistical rigor and are therefore of questionable validity. Compounding these basic limitations is the special difficulty in approximating the dosage of petroleum that is largely insoluble; this is less of a problem for bioassays of soluble dispersants. Most often the concentration of petroleum hydrocarbons in the water tested has not even been known. The most useful roles of laboratory bioassays seem to be in assessing relative toxicities of oils or dispersants, explaining phenomena observed in the field, and investigating toxicological mechanisms.

Most laboratory studies have been limited to acute (of two to four days duration) lethal effects. Chronic and sublethal effects have not been well studied. However, it is in these areas where laboratory studies may have their greatest value, considering the difficulty in controlling variables and running long-term experiments in nature.