Marianas Cetacean Surveys 2013: Updates on Our Satellite Tagged Short-finned Pilot Whales (July 12 – 26)

by Marie Hill, Allan Ligon, Adam Ü, and Mark Deakos

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Figure 1: Short-finned pilot whales spy-hopping in the waters off of Guam. (Photo credit: Adam Ü, collected under NMFS permit 15240).

Our last update on the satellite tagged short-finned pilot whales (Globicephala macrorhynchus) described them spending much time around Guam (check out our previous blog https://pifscblog.wordpress.com/2013/07/15/marianas-cetacean-surveys-2013-rota-summary-july-4-10/).  On July 11, two (128884 and 128886) were close to shore off the west side of Guam, while the third (128885) was at Santa Rosa Reef. Since then, the satellite tagged whale 128884 made an almost full clockwise circuit around Guam before traveling north beyond Rota (Figure 2).  We were hoping the whale might travel up to Saipan again as it had done in the beginning of July, but it turned back toward the south on 16 July.  The satellite tag stopped transmitting on 18 July when the whale was just northeast of Rota Bank.  The total tag transmission was 19 days.

Figure 2- Gm tag 128884

Figure 2: Track of satellite tagged short-finned pilot whale 128884 (12-26 July, 2013).

The second satellite tagged short-finned pilot whale (128885) has made some incredible movements since 12 July when it was hanging out at Santa Rosa Reef (figure 3).  Within a span of 5 days this whale traveled nearly 500 km south toward the Federated States of Micronesia, crossing over the Mariana Trench (Figure 3). The southwest end of the Trench, also known as Challenger Deep, is the deepest known point in the World’s Oceans (10.9 km or 6.8 mi deep). On 18 July, this whale returned to Guam and was recently located approximately 16 km off the northwest point of the Island on 26 July.  The tag has been transmitting for 27 days.

Figure 3- Gm tag 128885

Figure 3: Track of satellite tagged short-finned pilot whale 128885 (12-26 July, 2013).

The third and final satellite tagged short-finned pilot whale (128886), tagged the day after the first two, has primarily hung around Guam and north of the Island since 12 July (Figure 4).  On 17 July, both 128884 and 128886 were located in the same area approximately 30 km southeast of Rota (Figures 2 and 4).  Tag 128886 has been transmitting for 25 days.

Figure 4- Gm tag 128886

Figure 2: Track of satellite tagged short-finned pilot whale 128886 (12-26 July, 2013).

Stay tuned for more updates on the movements of our satellite tagged false killer whales (Pseudorca crassidens) and our surveys around Saipan, Tinian, and Aguijan.

The satellite tagging operations were conducted under NMFS permit 15240. Funding was provided by the NOAA Fisheries and the U.S. Pacific Fleet.

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