The Effects Of Oil-Contaminated Prey On The Feeding, Growth, And Related Energetics On Pink Salmon, Oncorhynchus Gorbuscha Walbaum, Fry

Abstract

Pink salmon, Oncorhynchus gorbuscha Walbaum, fry were exposed to oil-contaminated prey (OCP) in a series of experiments to determine the effects of oil exposure via the diet on the ability of pink fry to survive. Brine shrimp, Artemia salina, nauplii were contaminated with petroleum hydrocarbons by exposure to the water-soluble fraction (WSF) of Cook Inlet crude oil and fed to the fish. Feeding rates were measured for 10 days using OCP and for 5 days using uncontaminated prey (post-exposure period). In a separate experiment, fry growth was measured over a 50 day period. In another experiment, fry oxygen consumption, food absorption and utilization, and ammonia excretion was measured to determine the effects of OCP on fry metabolic activity. Fry feeding rates were reduced by exposure to OCP, and remained suppressed during the post-exposure period. Chronic exposure to OCP for 50 days reduced fry growth. OCP were not lethal to the fry. There was no change in fry oxygen consumption or ammonia excretion from exposure to OCP, but the fish exposed to OCP absorbed less food than controls and continued to absorb less food for 7 days after exposure. Results indicate that exposure to OCP can reduce fry growth primarily by reducing food intake, but additional nutrition is lost from the non-absorption of ingested food. Reductions in growth could decrease fry survival, and thereby reduce the number of returning adult pink salmon.