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Coast Guard says its planned use of ultra high frequency SONAR won’t harm marine life
The U.S. Coast Guard is proposing the nationwide use of high frequency and ultra high frequency SONAR systems which it says would better enable it to locate and classify underwater threats, such as swimmers, divers and underwater improvised explosive devices in U.S. ports, harbors and waterways.
In a recently completed preliminary environmental assessment, the Coast Guard has concluded that such SONAR devices – which operate at frequencies of 50 kiloHertz (kHz) and greater from mobile platforms – would have “no significant impact” on humans or marine mammals.
“Overall, the only marine species that are expected to be capable of hearing the HF and UHF SONAR under the Proposed Action are toothed whales, pinnipeds in water, and some clupeid fish,” said the Coast Guard in its draft programmatic environmental assessment (PEA), which it made public on Dec. 27.
The Coast Guard hopes to broaden its capability to locate and identify “targets of interest” (TOIs), such as explosives or other offensive devices, which could be delivered to underwater hulls, piers, shore structures and objects that have been submerged as a result of natural or man-made disasters.
“The use of HF (50 to 99 kHz) and UHF (1,000 kHz and higher) active SONAR technology would provide USCG operational commanders with the ability to locate, image, and classify underwater threats and other TOIs,” explained the Coast Guard document.
The SONAR equipment that the Coast Guard would operate is commercially available “off-the-shelf” equipment equivalent to many high-frequency “fish finders,” says the PEA. The proposed SONAR and such fish finders are similar in that they both include “low power with short pulse-width,” which is designed to focus in a single direction. Fish finders are typically focused downward, the study notes.
“These SONAR systems are within the hearing range of toothed whales (150 Hz to 180 kHz) and pinnipeds swimming in the water (75 Hz to 75 kHz),” the study continues. “Without mitigation, short-term, minor, adverse effects on toothed whales and pinnipeds would be expected from such SONAR operations.”
To mitigate these possible adverse effects, the Coast Guard envisions taking numerous steps to protect living marine resources, including monitoring the size of the safety zones, avoiding impact with the wildlife, consulting with the National Marine Fisheries Service, shutting down training exercises and R&D missions if marine mammals are detected in the area, operating the SONAR for not more than one week at a time, and more.
The Coast Guard plans to use such HF and UHF SONAR in all areas under its jurisdiction, along the U.S. continental coastline, Great Lakes, Hawaii, Alaska, the U.S. territories and inland operating areas.
However, the most probable location for use of the SONAR systems is in “militarily and economically significant ports,” says the draft PEA.
The public is invited to comment of the draft PEA and the accompanying “Finding of No Significant Impact” before January 31, 2011, by visiting www.regulations.gov and citing docket number USCG-2009-00166.
One anonymous commenter has already posted a no-holds-barred criticism: “huge massive doses of sonar frying the brains of marine life – I don’t think it should be allowed,” wrote Anonymous. “I do not approve of the nationwide use of these huge sonar impacts. it decimates earth and all living creatures. also one week is not a ‘short’ time. it is long enough to kill hundreds of thousands of marine life. this plan is terrible and needs shutdown.”
Further information about the Coast Guard’s proposed use of HF and UHF SONAR is available from Kenneth McDaniel, the deputy division chief, maritime security (counterterrorism) for the Coast Guard, at 202-372-2119 or [email protected].