Observations Of Cetaceans In The Central And Western Gulf Of Mexico
Authors: Avent R.M. 
Published: October 2008

ABSTRACT
With thousands of OCS oil and gas platforms in the Gulf, it has been questioned whether the many species of whales and dolphins are affected by physical structures, noise, effluents, spills, boat and air traffic, and explosive platform removals. This presentation reviews the results of recent major offshore vessel and aircraft surveys of marine mammals including the ongoing "GULFCET" study. It reviews the implications to the petroleum industry, and possible future research directions.

INTRODUCTION
The Minerals Management Service (MMS) has the responsibility for leasing, exploration, and development of submerged Federal lands on the U, S. Outer Continental Shelf (OCS). The MMS Environmental Studies Program (ESP) was initiated in 1973, largely to evaluate the environmental effects of OCS oil and gas activities on the OCS. In response to the Endangered Species Act (ESA) of 1973 and the Marine Mammal Protection Act (MMPA) of 1972, the ESP has funded an evolving series of studies on protected species potentially affected by OCS oil and gas operations. The ESA provides for the conservation of endangered and threatened species. It requires that Federal actions, including the regulation of petroleum activities, do not jeopardize species listed as threatened or endangered by the U.S. Fish and Wildlife Service. The MMPA of 1972, as amended, further requires that all marine mammals be protected, whether listed under the ESA or not. Through formal "Section 7" consultations with the National Marine Fisheries Service (NMFS), the MMS is required to assess the level of potential industry impact to the marine environment and its living resources. In response to these consultations and the recommendations of a 1989 protected species workshop (Tucker and Associates, 1990) the MMS supports studies on protected species in the Gulf of Mexico.
One of these is presently being conducted by the Texas A&M University at Galveston and the National Marine Fisheries Service. This "GULFCET" study calls for systematic shipboard, aerial, and acoustic census surveys over the outer continental shelf and slope, in the western and central Gulf, the areas most prone to deep petroleum exploration and development. In addition, attempts are being made to tag and track the movements of the endangered sperm whale.

METHODS
The methods used in the present deep water study include the following (see overall study area, Figure 1):Aerial surveys are conducted over the slope seasonally, employing dedicated aircraft, a NOAA deHaviland Twin Otter, when available. Preset flightlines are flown while trained observers identify and count animals and record observations, along with ocean conditions and position, on a portable computer. Limited departures from flightlines are made to refine species identifications and counts and to make and record behavioral observations.Shipboard surveys are conducted along preset transects as observers using large mounted binoculars identify and count animals. Hydrographic measurements and multichannel acoustic recordings are taken concurrently.