Cruise Report : NOAA Ship Gordon Gunter Cruise (GU18-06), November 10 - December 4, 2018, Trophic Interactions and Habitat Requirements of Rice's Whales

As part of a Resources and Ecosystems Sustainability, Tourist Opportunities, and Revived Economies (RESTORE) Science Program project, the Southeast Fisheries Science Center (SEFSC), in collaboration with Scripps Institute of Oceanography (SIO) and Florida International University (FIU), conducted a second research cruise dedicated to Rice's whales (Balaenoptera ricei) in the Gulf of Mexico (GoMex). The current known habitat area for the Rice's whale around the De Soto Canyon region (roughly from the Florida Panhandle to Tampa) in the northeast GoMex was designated as the primary study area based on previously documented sightings. Rice's whales, the only baleen whale resident to the GoMex, are most readily found in a small strip of water from De Soto Canyon southward along the continental slope within the study area, usually between depths of 180 m and 360 m.

The survey (GU18-06) was conducted 10 November - 4 December onboard the NOAA Ship Gordon Gunter along prescribed tracklines oriented along the 180-400 m isobaths, with a focus on the 200 m isobath. The survey had originally been scheduled to depart on 7 November 2018, but due to delays in foreign national security clearances it was delayed to 10 November. Between 21 and 24 November, the ship had to go into port (Pensacola, FL) for a crew member replacement due to medical reasons. During the mission, a total of 20 days were spent at sea.

Summary of objectives:

1. Deploy and recover short duration tags (camera and acoustic tags).

2. Collect tissue samples(biopsies) of Rice's whales for genetic, stable isotope, and persistent organic pollutants (POP) analyses.

3. Photo/video documentation of Rice's whales.

4. Conduct visual surveysto understand Rice's whale spatial distribution.

5. Deploy sonobuoys to collect recordings of the sounds produced by Rice's whales and of anthropogenic sounds.

6. Collect water samples around Rice’s whales to test for environmental DNA (eDNA).

7. Collect data on potential prey distribution based on acoustic backscatter using scientific echosounders (EK80).

8. Periodically collect vertical profiles of hydrographic parameters (e.g., temperature, salinity, oxygen concentration) via CTD and collect continuous underway surface physical oceanographic data.

At the time of data collection, Rice's whales (Balaenoptera ricei) were recognized as (Gulf of

Mexico) Bryde's whales (B. edeni); species denomination was changed to B. ricei after

recognition of the new species status in 2021 (https://doi.org/10.1111/mms.12776).

The Southeast Fisheries Science Center was authorized to conduct marine mammal research activities during the cruise under Marine Mammal Protection Act (MMPA) Permit No. 14450-05