Zooplankton underpin the health and productivity of global marine ecosystems. Here we present evidence that suggests seismic surveys cause significant mortality to zooplankton populations. Seismic surveys are used extensively to explore for petroleum resources using intense, low-frequency, acoustic impulse signals. Experimental air gun signal exposure decreased zooplankton abundance when compared with controls, as measured by sonar (∼3-4 dB drop within 15-30 min) and net tows (median 64% decrease within 1 h), and caused a two- to threefold increase in dead adult and larval zooplankton. Impacts were observed out to the maximum 1.2 km range sampled, which was more than two orders of magnitude greater than the previously assumed impact range of 10 m. Although no adult krill were present, all larval krill were killed after air gun passage. There is a significant and unacknowledged potential for ocean ecosystem function and productivity to be negatively impacted by present seismic technology.

Item Type:	Refereed Article
Keywords:	zooplankton, seismic survey, air guns, krill, ecosystem, acoustic impulse signals, larval, mortality
Research Division:	Agricultural, Veterinary and Food Sciences
Research Group:	Fisheries sciences
Research Field:	Aquaculture and fisheries stock assessment
Objective Division:	Environmental Management
Objective Group:	Marine systems and management
Objective Field:	Marine biodiversity
UTAS Author:	Day, RD (Dr Ryan Day)
UTAS Author:	Swadling, KM (Associate Professor Kerrie Swadling)
UTAS Author:	Fitzgibbon, QP (Associate Professor Quinn Fitzgibbon)
UTAS Author:	Watson, RA (Professor Reginald Watson)
UTAS Author:	Semmens, JM (Professor Jayson Semmens)
ID Code:	117696
Year Published:	2017
Web of Science® Times Cited:	64
Deposited By:	Sustainable Marine Research Collaboration
Deposited On:	2017-06-24
Last Modified:	2018-03-20
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