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Our Arctic Neighbors: Seismic surveys disturb fish, Norwegians find Research project in Arctic waters shows varying effects on different species, but fish did react to sound from seismic guns Sarah Hurst For Petroleum News
Seismic surveys do have an effect on fish, the Norwegian Petroleum Directorate has concluded after commissioning the Institute of Marine Research to conduct one of the largest-ever research projects on this issue. The research took place in summer 2009 off the district of Vesteralen in northwestern Norway, in an area that the oil and gas industry has been hoping the government will open up for licensing.
The sound waves from seismic data acquisition resulted in increased catches for some species and smaller catches for others, the NPD said in a release March 2.
“It appears that pollock may, to some extent, have withdrawn from the area, while other species seem to remain,” the NPD said.
Fish reacted to seismic “The survey clearly indicates that the fish reacted to the sound from the seismic guns,” the NPD said. “The most probable explanation for both the increased and reduced catches for the various species and fishing gear is that the sound waves from the seismic guns put the fish under some stress, causing more swimming activity. This would, for example, explain why more Greenland halibut went into the net, while long line catches of the same species declined.”
During the research the vessel Geo Pacific acquired 3-D seismic for just over a month in an area known as Nordland VII. Chartered fishing vessels fished in the area using both nets and lines, while the research vessel Hakon Mosby worked with another chartered fishing vessel to map the occurrence of fish and plankton using echo sounders and sonar. Stomach specimens were also taken from the catches, and recordings were made of the sound from the air guns on the seismic vessel.
“To a large degree, the mapping using echo sounders and sonar substantiates the results from the fishing tests,” the NPD said. “Analyses of the stomach contents in the fish caught did not reveal changes which could be attributed to the seismic survey. Neither were any changes in the distribution of plankton proven during the seismic data acquisition.”
The results from this study deviate from the results of previous studies, which have demonstrated considerable reductions in the catch rates for trawl and line fishing, the NPD noted. In one of the previous studies the seismic acquisition activity was concentrated within a smaller area, which entailed a stronger and more continuous sound impact on the fish than in the latest study, the NPD added.
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