As part of the long-term United States (U.S.) Navy-funded Marine Species Monitoring Program, from 1-14 August 2021, a combination of boat-based field effort and passive acoustic monitoring was carried out 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, 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, survey effort, encounters, and satellite tags deployed. Thirteen days of field effort were funded by the U.S. Navy, and an additional day was funded by NOAA Fisheries. Over the 14 days the research vessel covered 1,252 km of trackline over 82.2 survey hours. Access to PMRF was limited on three of 14 days due to live fire exercises. Survey effort was broadly spread across the southern one-third of PMRF, to the south of PMRF, and off the south shore of Kauaʻi. There were 35 encounters with nine species of marine mammals. A group of approximately 24 Fraser’s dolphins (Lagenodelphis hosei) were encountered, the first sighting of this species off Kauaʻi or Niʻihau in Cascadia Research Collective’s (CRC’s) field effort off these islands over 13 prior years and 24,224 km of effort (Baird 2016; Baird et al. 2021). There was a sighting of a group of seven Blainville’s beaked whales (Mesoplodon densirostris), only the seventh sighting of this species in CRC’s prior work off of Kauaʻi or Niʻihau. In addition, there was one sighting each of false killer whales (Pseudorca crassidens), and a Hawaiian monk seal (Neomonachus schauinslandi), three sightings of spinner dolphins (Stenella longirostris), four sightings of short-finned pilot whales (Globicephala macrorhynchus), five sightings of melon-headed whales (Peponocephala electra), six sightings of common bottlenose dolphins (Tursiops truncatus), and 13 sightings of rough-toothed dolphins (Steno bredanensis). Thirteen of the sightings (37%) were cued by acoustic detections from the Navy’s hydrophone range, including the one sighting of Blainville’s beaked whales and four sightings of melon-headed whales. In total, four genetic samples were obtained (one each from a Blainville’s beaked whale and a melon-headed whale, and two from false killer whales), and 40,161 photographs were taken for individual and species identification, although individual photo-identification matching has not been undertaken. Fourteen satellite tags were deployed on six different species, including 12 depth-transmitting SPLASH10-F (Fastloc®-Global Positioning System (GPS)) tags, one location-only SPOT6 tag, and one depth-transmitting SPLASH10 tag. One of the SPLASH10-F tags failed upon impact, but location data were received from the other 13 tags, and dive data were obtained from 11 of the 12 remaining depth-transmitting tags. Data from all of the tagged individuals overlapped temporally with Phase A of the SCC, and 11 of them overlapped temporally with Phase B of the SCC. Some of the tagged individuals remained on or close to PMRF during the duration of the tag deployments.
Citation:
Baird, R.W., C.J. Cornforth, K.A. Wood, S.E. Vasquez, A.E. Harnish, and M.A. Kratofil. 2022. Small-Boat Surveys and Satellite Tagging of Odontocetes on the Pacific Missile Range Facility, Kauai, in August 2021. Field survey report to U.S. Pacific Fleet by HDR, under Federal contract number N6247020D0016, Task Order No. N6274221F0107
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