Offshore Oil Exploration Linked to 50 Percent Reduction in Cod Catch

While a debate rages over the deleterious effects of seismic oil exploration on whales and dolphins, it turns out that our commercial fish stocks may be as vulnerable to the noise as are the marine mammals.

Cod populations are depleted everywhere, and the blame has been directed variously at fishermen for not managing stocks, at the protections afforded seals and sea lions, and warmer ocean temperatures -- but there is strong evidence that the failure of these fish populations to rebound may be tied to the loud sonar and airguns that are nearly constant in areas where these fish are found.

This was demonstrated in a study which carefully evaluated the impact of seismic airguns in a region where Norwegian fishermen have fished for centuries, and the results of the study are staggering -- up to 70 percent of the fish disappear immediately and do not return over the five days following exposure to the sound. The researchers also report that the biggest fish were the most likely to leave, and that all the fish were impacted for 18 nautical miles from the source.

"Effects of seismic shooting on local abundance and catch rates of cod ((Gadus morhua) and haddock )(Melanogrammus aeglefinus)" by A Engås, S Løkkeborg, E Ona, A V Soldal. Published on the web 09 April 2011. Canadian Journal of Fisheries and Aquatic Sciences, 1996, 53(10): 2238-2249, 10.1139/f96-177

"Abstract: To determine whether seismic exploration affected abundance or catch rates of cod (Gadus morhua) and haddock (Melanogrammus aeglefinus), acoustic mapping and fishing trials with trawls and longlines were conducted in the central Barents Sea 7 days before, 5 days during, and 5 days after seismic shooting with air guns. Add the possibility of oil spills which we already know are deadly to the marine environment, and it becomes clear why communities are united in their protest to keep the oil exploration at bay.

Seismic shooting severely affected fish distribution, local abundance, and catch rates in the entire investigation area of 40 × 40 nautical miles.Trawl catches of cod and haddock and longline catches of haddock declined on average by about 50 percent (by mass) after shooting started, which agreed with the acoustic abundance estimates; longline catches of cod were reduced by 21 percent.

Reductions in catch rates were observed 18 nautical miles from the seismic shooting area (3 × 10 nautical miles), but the most pronounced reduction occurred within the shooting area, where trawl catches of both species and longline catches of haddock were reduced by about 70 percent and the longline catches of cod by 45 percent; a relatively greater reduction was found (in catches and acoustic estimates) for large (>60 cm) than for small fish. Abundance and catch rates did not return to preshooting levels during the 5-day period after seismic shooting ended."

Research has shown that fish can be permanently deafened by seismic airguns, so it is possible that some of the fish are not able to survive or find mates.

In Newfoundland the fishery has collapsed, and the fishing villages and pristine environment are being replaced with oil refineries. Sure, the oil extraction and processing provides jobs -- but at what cost? People are losing a way of life that they cherish.

Cod fishing has dropped so significantly in the Gulf of Maine that quotas have dropped 77 percent, and fishermen feel that it will be difficult for smaller boats to make a living. The thought that the big oil companies can then move in and wipe out the efforts to rebuild the stocks must be galling, and even though the U.S. has temporarily suspended the decision to allow seismic exploration along the Eastern seaboard, it will be reevaluated when NOAA presents their decision on marine mammal acoustic quidelines. Fish don't seem to be considered important, and that is a mistake -- we can't eat petroleum oil.

We have finally come to understand that we can't just keep taking from one environment, depleting its resources before moving on to destroy the next one. Yet out of sight over the horizon or beneath the ocean surface, oil companies continue to follow the model we all recognize doesn't work. They profit, and we pay with our future.