Effects of Chronic Exposure to Petroleum Upon the Growth and Molting of Juveniles of the Arctic Marine Isopod Crustacean Mesidotea entomon

• Published in: Journal of the Fisheries Research Board of Canada
• Main Author: Percy, J. A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1978
• Subjects: General Medicine; Arctic; Norman Wells
• Online Access: http://dx.doi.org/10.1139/f78-114; http://www.nrcresearchpress.com/doi/pdf/10.1139/f78-114

Juveniles of the benthic marine isopod Mesidotea entomon were chronically exposed to different concentrations of water-soluble fractions of fresh and weathered Norman Wells crude oil and of fresh Pembina crude for 160 d. The 100% extracts contained 1.72, 1.12, and 0.56 ppm of oil (determined fluorimetrically), respectively. Most of the animals completed five or six molts before the end of the experiment. Long-term mortality was high in the 100% extracts of the oils (LT50 = 17, 17, and 41 d, for Norman Wells, Pembina, and weathered Norman Wells, respectively) but most of the animals molted at least once before dying. None of the deaths occurred in conjunction with the molt. Stimulation of the onset of the subsequent molt occurred in some exposure groups. A significant increase in the duration of the intermolt period only occurred at the highest oil concentrations. Effects on growth were slight at concentrations lower than that which is lethal during chronic exposure. Exposure to fresh Norman Wells crude depressed growth slightly, while Pembina crude slightly stimulated growth. Weathered Norman Wells severely inhibited growth at the highest concentration but stimulated growth slightly at lower concentrations. Key words: petroleum, growth, molting, arctic, isopod, Mesidotea entomon