HORMONAL AND REPRODUCTIVE EFFECTS OF LOW-LEVELS OF PETROLEUM FOULING IN MAGELLANIC PENGUINS (SPHENISCUS-MAGELLANICUS)

Petroleum fouling has many deleterious consequences for marine vertebr ates, ranging from increased energy expenditure to the death of the or ganism. We measured circulating levels of reproductive and adrenocorti cal hormones in Magellanic Penguins (Spheniscus magellanicus) that wer e partially covered with petroleum following a marine oil spill off th e Patagonian coast, and in a non-oiled control group. Levels of lutein izing hormone, androgens and estradiol, but not progesterone, were low er in oiled penguins than non-oiled control birds. Corticosterone was higher in oiled than control females, but did not differ and was basal in males. Few of the pairs with an oiled partner later established ne sts with eggs. Even low levels of oil fouling in Magellanic Penguins a ppear sufficient to interfere with reproduction. Oiled penguins that w ere held captive for washing had elevated levels of corticosterone, an d appeared to be stressed both by captivity and by the washing process .