Cruise Results: NOAA Ship Gordon Gunter Cruise GU-03-02 (23) 12 June - 18 August 2003, A Study of Oceanic Cetaceans in the Northern Gulf of Mexico

NOAA Ship Gordan Gunter departed Pascagoula, Mississippi on 12 June 2003 to conduct a marine mammal survey in the northern Gulf of Mexico (GOM). Operations occurred in the oceanic waters (>200m) from Brownsville, Texas to Key West, Florida seaward to the Exclusive Economic Zone (EEZ). Leg 1 (12 June- 1 July) was shortened by two days due to Tropical Storm Bill which was active in the survey area. All other legs departed and returned on time.

The U.S. Marine Mammal Protection Act (MMPA) requires that stocks of marine mammal species in U.S. waters be maintained at or above their optimum sustainable population level (OSP), defined as the number of animals which results in the maximum net productivity. To meet this requirement for each stock, the U.S. National Marine Fisheries Service (NMFS) estimates annual human-caused mortality and potential biological removal (PBR), the maximum number of animals that may be removed from a stock due to human activities (e.g., fisheries bycatch) while allowing the stock to reach or maintain its OSP. PBR is calculated following specific criteria using the estimated abundance of the stock, its maximum net productivity rate (theoretical or estimated), and a recovery factor (Barlow et al., 1995; Wade and Angliss, 1997).

The NMFS is required to prepare an annual Stock Assessment Report (SAR) for each stock to update abundance, stock structure, maximum net productivity, human-caused mortality, PBR, and status (e.g., Waring et al., 2001). Previous surveys of the oceanic northern GOM were done in conjunction with icthyoplankton surveys which have predetermined tracklines. Difficulties with these previous cruises have dealt with non-random survey effort and lack of complete coverage of the study area due to night time transits. The current study is the first dedicated to surveying cetaceans in these waters and will be instrumental in improving our estimates of the distribution and abundance of several species

This cruise report is used for documentation and timely communication of preliminary results immediately following the conclusion of the survey. Data, as presented here, are subject to change as further auditing and analysis occur.

The objectives of the cruise were

1. Conduct visual line-transect surveys for abundance estimation, and distribution of cetaceans in the northern GOM

2. Conduct acoustic line-transect surveys for abundance estimation, and distribution of cetaceans in the northern GOM

3. Collect photographic identification of individual cetaceans, including sperm whales

4. Collection of tissue samples (biopsies) of select cetaceans using a variety of devices including rifles and crossbows

5. Collection of sloughed skin and fecal samples of select cetaceans

6. Collect data on distribution and abundance of sea turtles

7. Conduct limited physical oceanographic sampling

The Southeast Fisheries Science Center was authorized to conduct marine mammal research activities during the cruise under Marine Mammal Protection Act (MMPA) Permit No. 779-1633.

Series : Southeast Fisheries Science Center Reference Document MMTD ; 2023-02

Download from supplied link

Open to everyone

CC0 1.0 UNIVERSAL

CC0 1.0 UNIVERSAL

Open to everyone