Sublethal effects of crude oil on a cold-water marine leech, Johanssonia arctica, following chronic exposure.

Abstract

Petroleum polyaromatic hydrocarbons (PAH) are known to affect many species of animals. Mortality and/or morbidity from acute toxicity are usually restricted to the immediate vicinity of a spill, seep or discharge. Subtle effects are sometimes not recognized unless long term observations are made. Several studies have shown that some species of invertebrates tend to accumulate and retain petroleum hydrocarbons for varying periods, sometimes with detrimental effects. In a previous communication, it was noted that water soluble fractions (WSF) of a crude oil distributed digestion and affected reproduction of a hematophagous marine leech, Johanssonia arctica. This leech is a benthic, cold-adapted species that is widely distributed on the continental shelf off eastern Canada especially on the Grand Banks where petroleum reserves have been recently discovered. The present study provides additional evidence that crude oil fractions not only alters egg production but also hatching of eggs and survival of the progeny.