In 1989, theExxon Valdez oil tanker ran aground in Prince William Sound, Alaska, leading to the spillage of hundreds of thousands of barrels of crude oil. The event was regarded as an international environmental disaster. Scientists are still analyzing the effects of the incident on the local environment.
One tranche of research has been conducted by researchers from the National Oceanic and Atmospheric Administration. Here researchers have found embryonic herring and salmon exposed to low levels of crude oil developed misshapen hearts. This is drawn from samples taken at the time (fish larvae) and subsequently analyzed as well as attempts to recreate what happened on a micro-scale under laboratory conditions. The studies involved exposing fish to low levels of oil and then transferring them to clean water and observing what happened in terms of behaviors and population numbers (including the birth rate.) The main physiological response was in relation to the heart, which led to offspring swimming more slowly and dying earlier.
One of the researchers involved, John Incardona, a research toxicologist at the Northwest Fisheries Science Center in Seattle, said in a research brief: “Metabolically, they’re different,” referring to the fish embryos, adding “they can’t grow as well. They can’t swim as fast.”
The events did not just affect pregnant fish at the time, they explain why fish stock remained suppressed for several years afterwards. Moreover, fish stocks in the affected region have never recovered to the pre-1989 levels. This has affected the local economy, given the importance of herring and pink salmon in terms of fishing and sales.
The findings have been published in the journal Scientific Reports (titled “Very low embryonic crude oil exposures cause lasting cardiac defects in salmon and herring”.) It is hoped that the findings will inform about the risks to fish stocks that can arise from any future oil spills.
