Marine Resources Assessment for the Marianas Operating ... - SPREP

AUGUST 2005 FINAL REPORT
were provided by Dr. Sally Mizroch and only represent confirmed (i.e., “sure”) sightings. From 1993 to
1997, there were three confirmed POP sightings of marine mammals in the Marianas MRA study
area: a Bryde’s whale, a killer whale, and a sperm whale. All three sightings were collected from
USCG vessels.
Mr. Mark Michael, owner of Dive Rota, has recorded opportunistic sightings of marine mammals and
sea turtles during SCUBA diving excursions at Rota from 1999 through 2004. These records, which
include protected species encounters at 17 different dive sites, were provided for inclusion in this
report. Although Mr. Michael is not a trained scientist, he is an experienced SCUBA diver with nearly
20 years of experience in the Marianas region. For several of the sighting records provided, species
identifications and group sizes were unable to be determined. However, geographic coordinates for
each of the dive sites where marine mammals and sea turtles had been observed were provided.
Mr. Scott Vogt, biologist with the Naval Facilities Engineering Command, Pacific, and Mr. Curt
Kessler, wildlife biologist with the USFWS, provided a number of opportunistic marine mammal
sighting records that were collected during helicopter overflights of the study area. Several incidental
sightings were recorded during monthly seabird surveys performed by USFWS and Navy personnel
over FDM. Other opportunistic sightings were documented during helicopter transit flights between
Saipan, Sarigan, and Anatahan. A land-based observation of a pod of spinner dolphins was also
provided. Nearly all of these sightings were documented as occurring at an estimated geographic
position (e.g., about 500 m northeast from Sarigan, CNMI) rather than at a specific set of
latitude/longitude coordinates.
Published Literature—Marine Mammal Sighting and Stranding Records
Published literature (e.g., journal articles, technical reports, and press releases) is often the most useful
media for presenting opportunistic sightings, strandings, and even whaling catches. For several of the
marine mammal species presented in this assessment, the sighting and stranding records or anecdotal
information contained within the following documents were the only sources of information available on
their occurrence patterns in the study area and vicinity. Since there have been no dedicated surveys
focusing on this group of animals around Guam and the CNMI, there is very little information available
regarding their occurrence in this area of the western North Pacific Ocean.
Anonymous (1962) described the stranding of a sperm whale off the coast of Inarajan, Guam in
September 1962 and provided a summary of other whale stranding events around Guam and Saipan
in years prior. Bordallo (1965) also mentioned this stranding in an article written about cetacean
intelligence and affection.
Anonymous (1974) and Randall et al. (1975) documented the sighting of an endangered dugong in
the center of Cocos Lagoon, Guam on 16 February 1974. This sighting was recorded during a marine
survey in which scientists attempted to determine the physiography, marine biota, and, to a lesser
extent, water circulation patterns within the lagoon.
Berggren (1996) detailed the opportunistic sighting of what appeared to be a group of humpback
whales in ocean waters off the entrance to Apra Harbor, Guam in January 1996. Recreational scuba
divers sighted this group of a dozen or more whales while aboard a charter boat.
Birkeland (1977) recounted his observation of a group of pilot whales moving northward off Uruno
Point, Guam in April 1977. Also commented on was a small school of unidentified dolphins that was
regularly seen at Double Reef (off Guam’s northwest coast) during the 1970s.
Darling and Mori (1993) took a trip to Saipan in February 1990, during which they interviewed
residents and listened for humpback whale songs. The authors concluded that humpback whales
were not regularly seen around the Northern Mariana Islands.