Cooperative Research on Sperm Whales and Their Response to Seismic Exploration in the Gulf of Mexico

Results from Minerals Management Service/U. S. Geological Survey-sponsored GulfCet studies have shown sperm whales occur year-round in deeper Gulf of Mexico waters. Sperm whales appear to favor water depths of about 1000 meters and also concentrate at three known locations in the GOM: (1) Florida Keys, (2) Mississippi River delta, and (3) Texas-Mexico border. These whales are endangered species and occupy an area subject to deepwater oil and gas exploration and development (the Mississippi River delta area), and also areas planned for future activity. A fundamental issue that must be addressed for assessment of all potential effects of Outer Continental Shelf activities raised under both the Endangered Species Act and Marine Mammal Protection Act, is further characterization of the sperm whales. In terms of industry activities, a key issue is potential effects of underwater noise, in particular, air guns used during seismic surveys. While other effects are of concern, the effects of noise are virtually undocumented and, unlike a potential event such as an oil spill, represent the results of normal industry activities. Discussions and expert opinions given at the 1999 Gulf of Mexico Protected Species Workshop provide further details on the need for this study.

Objectives:
The proposed study will focus on obtaining a detailed characterization of GOM sperm whales in terms of sex and age distribution in industry-active areas, genetic profiles, habitat use, and seasonal movement patterns. The normal behavior of whales will be studied and then compared to that observed when seismic vessels are operating in the study areas. Additional controlled experiments are planned to measure sperm whale response to a typical air-gun array. Research vessels and remote sensing devices will also obtain ambient noise measurements and physical oceanographic data to allow a detailed habitat characterization - mapping of both physical oceanographic features and ambient underwater noise levels will be correlated to sightings of sperm whales and all other cetaceans observed.