The MMS issued the NTL to offer interim guidance to the geophysical community on how to implement these mitigations. MMS Regional Director Chris Oynes stated that "Information is provided to surveyors about the ramp-up procedure, the exclusion zone for visual monitoring, the roles of visual observers, and reporting on marine mammals." All surveyors must use these measures during all seismic survey operations using airgun arrays in waters deeper than 200 meters (656 feet) throughout the Gulf of Mexico.
MMS had imposed the requirements on seismic activity as a result of a formal Biological Opinion on the part of the NOAA Fisheries. NOAA Fisheries issued the Opinion under the Endangered Species Act.
NOAA Fisheries was concerned that during the conduct of geophysical operations, surveyors using an airgun or airgun arrays could impact an endangered species, such as the sperm whale, which is protected under the Endangered Species Act.
This new NTL provides information for the calculation of a generic exclusion zone and procedures for visual monitoring of the exclusion zone during ramp-up procedures and during seismic survey operations. Briefly, ramp-up is achieved by a progressive buildup of energy output from a single airgun to the desired operational intensity of the air gun arrays. This is achieved by gradually increasing the number of guns fired simultaneously within an array. For complete details, please refer to NTL 2002-G07, "Implementation of Seismic Survey Mitigation Measures." Identical requirements will be imposed on permittees who file for geological and geophysical permits.
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