The Marine Environment of the Pitcairn Islands - Pew Environment ...

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Plate 27. The ‘Ocean Fish’ Pitcairn Islands stamp issue
from 2007 depicting six species of open-water fish
regularly caught off Pitcairn. Top row, from left to
right: dogtooth tuna Gymnosarda unicolor; wahoo
Acanthocybium solandri; mahi-mahi Coryphaena
hippurus; bottom row, from left to right: yellowfin tuna
Thunnus albacares; giant trevally Caranx ignobilis; bonito
Sarda chiliensis lineolata.
array of gastrointestinal, neurological and cardiological
symptoms with treatment options being ineffective or
very limited (Dickey and Plakas, 2009). In particular, the
coral reefs of Mangareva in the Gambier Islands hold
large amounts of the dinoflagellate Gambierdiscus
toxicus, a ciguatoxin precursor which attaches itself to
algae and traverses the food chain bioaccumulating in
carnivorous fin fish. High subsequent and ongoing rates
of intoxications by ciguatera recorded in the Gambier
Islands have been associated with French nuclear testing
in the area around Moruroa Atoll and associated military
infrastructure development on Mangareva conducted
during the period 1968 to the mid-1970s, although the
environmental pathways to the outbreak have not been
established. While the existing presence of ciguatera
is a potential barrier to the development of small-scale
commercial fisheries in the Pacific Islands more generally,
the Secretariat of the Pacific Community has proposed
that the Pitcairn community may be in a good position to
develop their inshore reef fisheries commercially for export
to Mangareva (Michel Blanc, pers. comm., Nov. 2011),
although the purchase and installation of a blast freezer
will be necessary to ensure production meets food safety
regulation standards. However, as yet no assessment of
stocks has been undertaken and the economics of such a
venture have to be studied in detail.
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17. ‘Nearshore waters’ here are defined as extending to
approximately 2 km from low water mark or shallower
than the 100 m depth contour.
18. Note that Sargassum odontocarpum was originally
recorded as Sargassum coriifolium by Tsuda (1976).
The taxonomy of the genus Sargassum in French
Polynesia was revised in 2008 (Mattio et al., 2008).
19. The Foraminifera (“hole bearers”), or forams for short,
are a large group of amoeboid protists which are
among the commonest plankton species. They have
reticulating pseudopods, fine strands of cytoplasm
that branch and merge to form a dynamic net. They
typically produce a test, or shell, which can have
either one or multiple chambers, some becoming
quite elaborate in structure. These shells are made of
calcium carbonate (CaCO3) or agglutinated sediment
particles. About 275,000 species are recognised,
both living and fossil. They are usually less than 1 mm
in size, but some are much larger, with the largest
species reaching up to 20 cm. [Wikipedia entry,
24Nov11. URL: en.wikipedia.org/wiki/Foraminifera].
20. Note that only eight species of Foraminifera were listed
from all four Pitcairn Islands by Palomares et al., 2011.
21. Ostracoda is a class of the Crustacea, whose members
are sometimes known as seed shrimps because of their
appearance. Some 65,000 species (13,000 of which are
extant taxa) have been identified, grouped into several
orders. Ostracods are small crustaceans, typically around
1 millimetre in size. Their bodies are flattened from
side to side and protected by a bivalve-like, chitinous
or calcareous carapace or ‘shell’. Ecologically, marine
ostracods can be part of the zooplankton or (most
commonly) they are part of the benthos, living on or
inside the upper layer of the seafloor.
22. The figure of 47 species consists of 28 named species, three
new genera and 16 new species (Whatley et al. 2004).
23. (http://library.puc.edu/pitcairn/studycenter/
cruiseship.shtml, last accessed 7/12/2011).
3.2 Henderson
KEY FACTS
Name HENDERSON Island type Elevated coral atoll
Location 24°21’S, 128°19’W Distance/bearing from
nearest island(s)
The Marine Environment of the Pitcairn Islands: Pitcairn The Marine Environment of the Pitcairn Islands: Henderson
Approx. 200 km ENE of Pitcairn; and
approx. 360 km W of Ducie
Dimensions 9.6 km long x 5.1 km wide Land area 43 km 2 (4,310 ha)*
Altitude Sea level to approx. 33 m Length of coastline 26.4 km
Origin of name European discovery by Pedro Fernandez de Quiros, who passed without landing in 1606 and
named it San João Baptista. Received current name in 1831 after it was visited by the British ship
Hercules in 1819 under Capt. Henderson. From 1819–1831, however, it was known as Elizabeth
Island.
Population/visitors Uninhabited. Occasional 2–3 day visits by Pitcairners to harvest miro wood for carving. A stopoff
for a few cruise ships (e.g. World Discoverer), whose passengers land for 2–3 hours on North
Beach.
Status World Heritage Site (1988); Endemic Bird Area; Important Bird Area; Alliance for Zero Extinction
site (Brooke, 2010). Proposed Ramsar site (2005).
Overview One of the least disturbed raised coral atolls in the world, with its terrestrial ecosystems largely
intact. The island supports a large breeding population of seabirds, including the endemic
Henderson petrel Pterodroma atrata and also has four endemic landbirds, one of which is a
flightless rail. The beaches and reef flats are important for wintering bristle-thighed curlews
Numenius tahitiensis. An attempt was made to eradicate rats from the island in 2011 but this
was unsuccessful.
(Information extracted from various sources including the RSPB’s A Directory of Wetlands in Oceania:
http://www.wetlands.org/RSIS/WKBASE/OceaniaDir/Pitcairn.htm)
* Updated figure for land area obtained in 2011 using GPS. Previously, the figure was 37 km2 (3,700 ha)
(RSPB, Henderson Island Restoration Project).
Figure 8. Henderson Island (after Irving, 1995).
Plate 29. (right) East Beach, Henderson.
(Photo: R.A. Irving)
Plate 28. Aerial view of the north end of the East Beach,
Henderson. (Photo: SPSCEPI)
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