As part of the long-term United States (U.S.) Navy-funded Marine Species Monitoring Program, from 16–24 August 2022, Cascadia Research Collective (CRC) carried out a vessel-based field effort in conjunction with passive acoustic monitoring undertaken by U.S. Navy (Navy) scientists on and around the underwater hydrophone ranges of the Pacific Missile Range Facility (PMRF). The effort was timed to occur immediately prior to the start of Phase B of a Submarine Command Course (SCC), to allow for collection of movement and dive data that could be used to examine exposure and response of cetaceans to Navy mid-frequency active sonar (see Henderson et al. 2021). This interim field survey report provides a summary of boat-based survey methodology (Appendix 1), survey effort (Figure 1), encounters (Table 1), and satellite tags deployed (Table 2; Figures 2-12). Eight days of field effort were funded by the Navy, and an additional day was funded by the Pacific Islands Fisheries Science Center. Over the nine days, the research vessel covered 1,238 km of trackline over 63 survey hours. Survey effort was broadly spread across the southern one-third of and to the south of PMRF (Figure 1). There were 26 encounters with seven species of cetaceans (Table 1). A group of approximately 100 striped dolphins (Stenella coeruleoalba) was encountered, only the second time this species has been seen off Kauaʻi in the 14 years of CRC field effort off Kauaʻi and Niʻihau since 2003. Two groups of Blainville’s beaked whales (Mesoplodon densirostris) were encountered, representing the eighth and ninth times that this species has been encountered off Kauaʻi during CRC field work. In addition, there were two sightings of melon-headed whales (Peponocephala electra), three sightings each of short finned pilot whales (Globicephala macrorhynchus) and common bottlenose dolphins (Tursiops truncatus), seven sightings of rough-toothed dolphins (Steno bredanensis), and eight sightings of spinner dolphins (Stenella longirostris). Ten of the sightings (38%) were cued by analysts interpreting acoustic detections from the Navy’s hydrophone range, including one of the Blainville’s beaked whale sightings and the striped dolphin sighting. In total, 33,071 photographs were taken of all seven encountered cetacean species for individual and species identification. There were 11 tagging attempts. One tag was lost, and 10 tags were deployed on five different species: eight depth-transmitting SPLASH10-F (Fastloc®-Global Positioning System (GPS)) tags and two depth-transmitting SPLASH10 tags (Table 2). Location data1 were received from all 10 tags (Figures 2-12), and dive data from nine of the 10. Six tags were deployed during Phase A of the SCC (Table 2). Two of those tags stopped transmitting before the start of Phase B of the SCC, but four additional tags were deployed prior to Phase B (Table 2). Thus, data from eight of the tagged individuals overlapped temporally with Phase B of the SCC (Table 2). Data from all individuals have been provided to collaborating researchers with NIWCPAC for analyses of received levels of MFAS, and are being examined for potential behavioral changes associated with MFAS exposure. Some of the tagged individuals remained on or close to PMRF during the duration of the tag deployments (e.g., see Figures 2, 3, and 8). Additionally, one fecal sample (from a short-finned pilot whale) and two eDNA samples (from Blainville’s beaked whales) were collected. The fecal sample has been archived with the University of Hawaiʻi Health and Stranding Lab for future prey DNA and hormone chemistry analyses, and the eDNA samples have been contributed to a larger beaked whale genetics project coordinated through the University of Auckland and funded by the Office of Naval Research.
Citation:
Baird, R.W., C.J. Cornforth, J.K. Lerma, J.F. Shaff, A.E. Harnish, A. Vanderzee, and M.A. Kratofil. 2023. Small-boat Surveys and Satellite Tagging of Odontocetes on the Pacific Missile Range Facility, Kauaʻi, in August 2022. Field survey report to U.S. Pacific Fleet by HDR, under Federal contract number N62470-20-D0016, Task Order No. N62742-21-F0107. February 2023.
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