Norwegian study reveals potentially disastrous effects of petroleum production on cod stocks | WWF

Norwegian study reveals potentially disastrous effects of petroleum production on cod stocks

Posted on
05 November 2001
Finnmark, Norway: A recent study by The Norwegian Institute for Marine Research (IMR) has revealed alarming new information about the effects of petroleum by-products on cod in the Norwegian Barents Sea, one of the world’s most important spawning areas for economically important fish species.
When crude oil and gas is extracted from a reservoir it is frequently accompanied by water. This is either naturally present or has been injected into the reservoir to maintain pressure for production. The amount of so-called "produced water" increases with maturity of the oil/gas field. At the end of a field’s life, produced water may account for as much as 98% of the extracted volume.
In addition to oil particles, produced water also contains heavy metals, radionucleids, alcylic phenols and aromatic hydrocarbons (including PAH). Current offshore environmental regulations, however, only limit the oil content in produced water discharged into the sea. There are no regulations on other dissolved substances. In 1999, more than 15 tonnes of alcylic phenols where discharged from installations in Norway.
Little is known about the long-term impacts of these pollutants in the marine environment, however, alcylated phenols are suspected to have endocrine disrupting effects. The study by Norwegian scientists compared cod exposed to alcylated phenols with unexposed control groups. The results were alarming:
- Female cod exposed to alcylated phenols suffered a significant reduction in their oestrogen level
- Exposed female cod developed fewer eggs than unexposed individuals
- Exposed male cod started producing the protein vitellogenin. This protein constitutes the main portion of yolk in cod eggs.
The most disturbing finding was that these effects became apparent at extremely low concentrations of alcylated phenols, which are found in areas surrounding oil installations.
Equally alarming is the fact that this study only scratches the surface of potential impacts of produced water. Scientists now know something about one effect of petroleum extraction on one species in one area. The impacts of other substances, on other species and in other environments are still largely unknown.
WWF is encouraging Norway’s newly appointed conservative coalition government to put plans for a massive new petroleum project in the Norwegian Barents Sea on hold until an environmentally sound management plan for this marine region is developed.
Shell Oil and Statoil have announced that they will postpone all oil operations in the fragile Lofoten area, the main breeding grounds of Atlantic cod, until the conflict between fisheries and oil interests are resolved.
For more information, contact the following staff of the Institute of Marine Research:
Asbjørn Svardal, Senior Researcher; Tel.: + 47 55 23 85 19 Roald Vaage, Administrative Director; Tel.: + 47 55 23 85 19 Jo Høyer, Chief of Information; Tel.: + 47 55 23 85 21 or + 47 95 11 92 16
or contact
Andreas Tveterass
Marine Conservation Officer, WWF-Norway
Tel.: + 47 22 03 6 512; Email:
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