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Cruise KOK0510 consisted of three Pisces V dives to the submerged flanks of Tutuila,
American Samoa, specifically the coral reef platform of Taema Bank, and the submerged
caldera forming Fagatele Bay and Canyon. In addition, a night-time program of Sea
Beam 210 bathymetric mapping was conducted along the north side of the island to fill in
a data gap from previous multibeam surveys in that region. Night-time deployments of
the RCV-150 were also planned, but could not commence due to mechanical difficulties
with the ROV. The overall objectives of the cruise were the characterization and groundtruthing
of underwater features previously mapped in sonar, and for areas below the reach
of SCUBA, the estimation of the amount of live bottom, the species identification of fish
and invertebrates, and the assessment, where possible, of benthic change within the coral
reefs encountered. These observations were made toward an ultimate goal of groundtruthing
previous benthic terrain maps (geo) made in the region, as well as informing the
preparation of future benthic habitat maps (biogeo). Research questions guiding the
objectives include: (a) What are the significant deep-water coral reef habitats, relative to
the territory’s coastal ecology and current initiatives for sanctuary management (i.e.,
areas of 20% or greater coral cover as mandated for protection)? (b) Where are these
critical habitats located, and with what major species are they associated with? (c) Which
habitats appear to be “biological hotspots” (e.g., areas of high biodiversity), and what are
the implications for coral reef conservation and management? For example, which sites
should be deemed of special biologic significance (such as a no take zone within a pilot
marine protected area)?
All three dives were extremely successful with a cumulative bottom time of 18 hours and
identification at both sites of 32 species of invertebrates and 91 species of fish, at least 9
of which are “new records” for American Samoa. The base of extensive live bottom for
Taema Bank (coral cover of 20% and greater) was identified at a depth of 36 m.
Alternating sections of carbonate reef and basalt were observed at~185-220 m depth
along the west walls of Fagatele Canyon, and large, grooved mass-wasting scarps were
noted at ~300-400 m depth near the base of the south central wall of Taema Bank. No
evidence of eutrophication or slurry from Pago Pago harbor was seen on the south side of Taema Bank. Sea Beam mapping on the north flank of Tutuila revealed 3 new cones that
will eventually be added to the Scripps Biogeosciences Seamount Catalog (EarthRef.org).
Subsequent benthic habitat maps that may be created with the aid of these data should be
of great use for ongoing studies by the American Samoa Government’s Department of
Marine and Wildlife Resources (DMWR), the Fagatele Bay National Marine Sanctuary
(FBNMS), the American Samoa Coastal Management Program, and the National Park of
American Samoa (NPAS); including the selection of sites for habitat class designation
and protection (e.g., no-take marine protected areas, a major American Samoa initiative),
development of marine park monitoring protocols, and general understanding of species
composition and abundance. In addition, we were pleased to have 2 local secondary
school teachers join the cruise as observers. These teachers were recently involved in a
marine science workshops co-funded by the Fagatele Bay National Marine Sanctuary and
the American Samoa Coral Reef Advisory Group, and will be using selected videos,
photos from the cruise, and perhaps some of the GIS data sets, directly in their
classrooms. Local media coverage of the cruise included a radio interview and an article
in Samoa News (facilitated by Nancy Daschbach of FBNMS and Peter Craig of NPAS). |
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