Scientists from the Protected Resources Division have successfully deployed satellite tags on killer whales and minke whales in the Antarctic and are currently tracking their locations.
Satellite Tracking of Marine Mammals in McMurdo Sound:
Robert Pitman and John Durban recently finished working with colleagues at McMurdo Station in Antarctica as part of a NSF-funded project on apex predators. In addition to capturing photographs of individual Antarctic killer whales for identification, which will help them estimate the population size of these whales, they also successfully deployed satellite tags on killer whales and Antarctic minke whales in McMurdo Sound. The data from these satellite tags provide insight into the foraging behavior of these whales as the scientists track the dive depths and movements of each whale.
Nine of the ten satellite tags deployed by the team (now including 6 type C killer whales and 3 Antarctic minke whales) continue to work very well, with dive and location data coming in for both species. Of note so far, the killer whales are diving to over 700 meters; minkes in the same area are regularly diving to only 80 meters. In addition, approximately 3 hours of acoustic recordings of the distinctive Ross Sea Killer Whale were obtained for comparative analyses, and ten biopsy samples were collected to study trophic interactions between minkes and killer whales.
Satellite Tracking of Marine Mammals near the Antarctic Peninsula:
John Durban has transferred from McMurdo Station to the Antarctic Peninsula where he and Holly Fearnbach will continue studies evaluating the ecosystem interactions of killer whales as top predators. John, Holly and (later) Robert Pitman are being hosted by Lindblad Expeditions onboard the expedition ship National Geographic Explorer until early February, when operations will transfer to the National Science Foundation charter vessel R/V Point Sur.
Already the team has deployed a satellite LIMPET tag and a depth-recording satellite tag on two Type B (small form) killer whales off the Antarctic Peninsula. The LIMPET tag is a location-only transmitter tag, intended to enable longer term tracking into the winter months and high resolution tracking in the shorter term to facilitate relocation for follow up studies. In comparison, the depth-recording tags will be used to remotely monitor movement and diving behaviors over the coming weeks, to infer possible prey species and predation strategies; later work aboard the Pt. Sur will focus on prey mapping/sampling in important foraging areas identified from the tag data.
Although the team has observed these killer whales feeding on brushtail penguins at the surface, the previously-deployed LIMPET tag continues to transmit astounding dive-depth data, dives regularly greater than 500 meters and even in excess of 700 meters on occasions. Their work in the coming weeks will focus on identifying the prey they are targeting at these depths. After returning to Ushuaia (Tiera del Fuego, Argentina) to change out the guests onboard, they are now southbound again in the South Shetland Islands. The team expects more killer whales in the coming days.
- To learn more about killer whale research conducted at the Southwest Fisheries Science Center, please visit this website.