Air guns

Observations of marine fish and invertebrates on an inshore reef were made using TV and acoustic tags one week before, during, and four days after a seismic triple G. airgun (three synchronised airguns, each gun 2.5 l and 2000 psi) was deployed and repeatedly fired. The guns were fired once/min for eight periods on four days at different positions. The structure and intensity of the sound of each triple G. gun explosion was recorded and calibrated. Peak sound pressure levels of 210 dB (rel to 1 mPa) at 16 m range and 195 dB (rel to 1 mPa) at 109 m range were measured at positions where the fish were being observed. The final position of the triple G. gun, at 5.3 m range, had a peak pressure level of 218 dB (rel to 1 mPa). Neither the fish, nor the invertebrates, showed any signs of moving away from the reef. Firing the guns did not interrupt a diurnal rhythm of fish gathering at dusk and passing the TV camera position while the guns were firing. The longterm day-to-night movements of two tagged pollack were slightly changed by the arrival and banging of the guns particularly when positioned within 10 m of their normal living positions. Those reef fish, watched by the TV camera, always showed involuntary reactions in the form of a Mauthner cell reflex, C-start, at each explosion of the guns at all ranges tested (maximum range was 109 m, 195 dB rel to 1 mPa). When the explosion source was not visible to the fish, the C-start reaction was cut short and the fish continued with what they were doing before the stimulus. When the G. gun rack was sunk to the seabed (depth 14 m) visible to the fish and the TV camera, those fish that were observed approaching the G. gun rack when the guns were fired were seen to turn and flee from the very visible explosion. When the gun rack was suspended midwater (5 m depth) and just outside visible range at 16 metres, the fish receiving a 6 ms peak to peak, 206 dB (rel to 1 mPa) pressure swing exhibited a C-start and then continued to swim towards the gun position, their intended swimming track apparently unaltered. The sound of the G. guns had little effect on

Air guns used in oil industry seismic surveys have the capacity to change fish catch rates, but no previous work has demonstrated this effect in shallow water or in Arctic oilfields. Long-term monitoring of fish catches using four fyke nets allowed assessment of changes in catch rates during a 2014 seismic survey in Prudhoe Bay, Alaska. Fyke net locations were instrumented with both conventional hydrophones and vector sensors. Catch rates were generally within the range of those found in 27 previous sampling seasons. The effect of air guns on eight species was assessed using a modified Before-After/ Control-Impact analysis, with historical data and 2014 data as the Before-After components of the analysis and days without and with air gun activity as the Control-Impact components. Results showed significant changes associated with air guns in catch rates at one or more nets at p < 0.1 for all eight species and at p < 0.05 for seven of the eight. Changes included both increased and decreased catch rates, perhaps reflecting displacement of fish in response to air gun sounds throughout the study area. Measured sound pressure levels associated with air gun pulses were low and usually undetectable close to the fyke nets, reflecting the loss of low frequencies in shallow water (~1.5 m). Attempts to measure particle velocities failed when wind-driven surface waves overwhelmed vector sensors. However, fish responses may have been related to changes in particle motion associated with air gun sounds.

Observations of marine fish and invertebrates on an inshore reef were made using TV and acoustic tags one week before, during, and four days after a seismic triple G. airgun (three synchronised airguns, each gun 2.5 l and 2000 psi) was deployed and repeatedly fired. The guns were fired once/min for eight periods on four days at different positions. The structure and intensity of the sound of each triple G. gun explosion was recorded and calibrated. Peak sound pressure levels of 210 dB (rel to 1 mPa) at 16 m range and 195 dB (rel to 1 mPa) at 109 m range were measured at positions where the fish were being observed. The final position of the triple G. gun, at 5.3 m range, had a peak pressure level of 218 dB (rel to 1 mPa). Neither the fish, nor the invertebrates, showed any signs of moving away from the reef. Firing the guns did not interrupt a diurnal rhythm of fish gathering at dusk and passing the TV camera position while the guns were firing. The longterm day-tonight movements of two tagged pollack were slightly changed by the arrival and banging of the guns particularly when positioned within 10 m of their normal living positions. Those reef fish, watched by the TV camera, always showed involuntary reactions in the form of a Mauthner cell reflex, C-start, at each explosion of the guns at all ranges tested (maximum range was 109 m, 195 dB rel to 1 mPa). When the explosion source was not visible to the fish, the C-start reaction was cut short and the fish continued with what they were doing before the stimulus. When the G. gun rack was sunk to the seabed (depth 14 m) visible to the fish and the TV camera, those fish that were observed approaching the G. gun rack when the guns were fired were seen to turn and flee from the very visible explosion. When the gun rack was suspended midwater (5 m depth) and just outside visible range at 16 metres, the fish receiving a 6 ms peak to peak, 206 dB (rel to 1 mPa) pressure swing exhibited a C-start and then continued to swim towards the gun position, their intended swimming track apparently unaltered. The sound of the G. guns had little effect on

On 19 December 2014, Spain presented a third partial submission for the delineation of the Extended Continental in the area west of the Canary Islands to the Commission on the Limits of the Continental Shelf (CLCS) according to the United Nations Convention on the Law of Sea (UNCLOS). The Canary Islands are located within a NE-SW 1,350 km long ridge of hotspot-inferred volcanic islands and seamounts (composed by more of 100, from Lars to Tropic seamounts). This submission has been documented with an extensive dataset specifically obtained for the project during ten oceanographic cruises between 2010 and 2014 aboard the Spanish research vessels Hespérides, Sarmiento de Gamboa and Miguel Oliver. This new dataset allows to investigate an area of 440,000 km2 with acoustic backscatter images and multibeam echosounder bathymetric (MBES) data (Simrad EM-12, EM-120 and EM-302, and Atlas HYDROSWEEP DS), a dense network of 65,800 km of very-high resolution (VHR) seismic lines (including chirp...

Seismic surveys have the potential to affect marine life, including commercially and recreationally important finfish and invertebrate species and their prey. There is, however, considerable uncertainty around the degree of impact and relevant pressure-response pathways across the different taxonomic groups

Air guns used in oil industry seismic surveys have the capacity to change fish catch rates, but no previous work has demonstrated this effect in shallow water or in Arctic oilfields. Long-term monitoring of fish catches using four fyke nets allowed assessment of changes in catch rates during a 2014 seismic survey in Prudhoe Bay, Alaska. Fyke net locations were instrumented with both conventional hydrophones and vector sensors. Catch rates were generally within the range of those found in 27 previous sampling seasons. The effect of air guns on eight species was assessed using a modified Before-After/Control-Impact analysis, with historical data and 2014 data as the Before-After components of the analysis and days without and with air gun activity as the Control-Impact components. Results showed significant changes associated with air guns in catch rates at one or more nets at p &lt; 0.1 for all eight species and at p &lt; 0.05 for seven of the eight. Changes included both increased a...

On 19 December 2014, Spain presented a third partial submission for the delineation of the Extended Continental in the area west of the Canary Islands to the Commission on the Limits of the Continental Shelf (CLCS) according to the United Nations Convention on the Law of Sea (UNCLOS). The Canary Islands are located within a NE-SW 1,350 km long ridge of hotspot-inferred volcanic islands and seamounts (composed by more of 100, from Lars to Tropic seamounts). This submission has been documented with an extensive dataset specifically obtained for the project during ten oceanographic cruises between 2010 and 2014 aboard the Spanish research vessels Hespérides, Sarmiento de Gamboa and Miguel Oliver. This new dataset allows to investigate an area of 440,000 km2 with acoustic backscatter images and multibeam echosounder bathymetric (MBES) data (Simrad EM-12, EM-120 and EM-302, and Atlas HYDROSWEEP DS), a dense network of 65,800 km of very-high resolution (VHR) seismic lines (including chirp...

On 19 December 2014, Spain presented a third partial submission for the delineation of the Extended Continental in the area west of the Canary Islands to the Commission on the Limits of the Continental Shelf (CLCS) according to the United Nations Convention on the Law of Sea (UNCLOS). The Canary Islands are located within a NE-SW 1,350 km long ridge of hotspot-inferred volcanic islands and seamounts (composed by more of 100, from Lars to Tropic seamounts). This submission has been documented with an extensive dataset specifically obtained for the project during ten oceanographic cruises between 2010 and 2014 aboard the Spanish research vessels Hespérides, Sarmiento de Gamboa and Miguel Oliver. This new dataset allows to investigate an area of 440,000 km2 with acoustic backscatter images and multibeam echosounder bathymetric (MBES) data (Simrad EM-12, EM-120 and EM-302, and Atlas HYDROSWEEP DS), a dense network of 65,800 km of very-high resolution (VHR) seismic lines (including chirp...