INTRODUCED MARINE SPECIES IN PAGO ... - Bishop Museum

Skelton, P. A., Algae survey report
The introduction of algae into a new place is either accidental, that is attached to ships hulls,
equipment used in the aquatic environment, shells of cultured animals and ship’s ballast, or
deliberate for animal feed or aquaculture purposes (agar and carrageenan extraction).
American Samoa’s algal flora was first assessed by William Albert Setchell in the early 1920s
(Setchell 1924), and 100 species were compiled. Setchell’s collections were limited to shallow
intertidal areas, with a few subtidal specimens obtained by dredging. No other major algal work is
known from American Samoa since Setchell, but the efforts of some sporadic and itinerant algal
collectors passing through the islands have yielded some new additions to the flora of the islands.
The recent publication of the South Pacific Reef Plants by Diane and Mark Littler (2003)
illustrates 33 algal species from American Samoa. The Littlers’ algal collections are housed at the
Smithsonian Institution, Washington. The last two phycologists that visited the islands are Drs
Paul Gabrielson and Peter Vroom, their collections are yet to be curated. American Samoan
algae are also noted from reef ecologists’ reports (Dahl 1971, Birkeland et al. 1987, Hunter et al.
1993, Wilkins in Birkeland et al. 1995). Moreover, American Samoa algae were included in the
algal checklist of the Samoan Archipelago by Skelton and South (1999), where 198 taxa were
listed. The checklist is currently being updated as past collections housed at the Bishop Museum
and the University of California at Berkley Herbarium are examined, together with continuing field
surveys, adding new records as well as new species to the flora. A total of 318 species have so
far been documented (Skelton unpubl. data) for the Archipelago.
None of the past studies address the issue of introduced algal species. However, they provide an
excellent foundation whereby determination of the status of algal introductions can begin. With
continuing monitoring of the coral reef ecosystem coupled with the knowledge gleaned and
accumulated from past studies, managers should be able to determine the best course of action
to safeguard the integrity of the marine environment of American Samoa. This report provides the
first assessment of introduced marine species for the Archipelago.
Materials and Methods
Surveys were carried out from 13-17 October 2002. Algae were collected by snorkeling or by
using Scuba gear, wading or shore-collecting, often with the assistance of a diving knife. Smaller
and fragile algae were collected together with the substratum they were growing on.
All specimens were treated with 4-percent formalin (10% formaldehyde) in seawater solution, and
soaked in plastic bags or plastic vials for two days, before draining and repacking them for
shipment.
Ten sites were surveyed (Table 1), although two smaller collections were made at Leone and
Amalau.
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