Snapping shrimp noise near Gladstone, Queensland

The intensity of the noise generated by snapping shrimp between 0.6 and 12.5 kHz was measured from Auckland Wharf to the end of the dredged channel leading into Gladstone, Queensland, Australia, and on a route out across to the edge of the Great Barrier Reef. The noise was recorded about every nautical mile within the channel and every 5 miles across the reef. Water depths varied between 11.5 and 58 m, with sites ranging from just a few meters from piers to 82 km from the mainland. Intense snapping shrimp noise was found at all sites and was the dominant source of ambient noise. Within the channel the noise exceeded that which would be expected from wind generated noise during sea state 7. Across the reef the noise levels were lower, but still exceeded that from sea state 3 wind generated noise. Comparison is made with other published snapping shrimp noise spectra which show differences in both level and shape.