Ciguatera in the Gilbert Islands— Cooper 
431 
miles, the population in 1958 was 1,142, and 
the average annual rainfall is 48 inches. There is 
a poor anchorage on the western side of the 
island, opposite the only village. Toxic fish have 
never been reported from Tamana. 
Arorae 
Arorae is a small reef island and the most 
southerly of the Gilbert Islands. There was a 
population in 1958 of 1,551 and a land area of 
5 square miles. There are three anchorages, all 
described as poor. Toxic fish have never been 
reported from Arorae, and both the Tamana and 
Arorae people are most indignant at the idea 
that either island could ever produce a toxic fish. 
The fringing reefs on Arorae are wide, espe- 
cially in the north and south. A ship is reputed 
to have been wrecked on the southernmost tip 
of Arorae, but there is no sign of any remains. 
Ocean Island 
Ocean Island, lying 160 miles west-southwest 
of Tarawa, is not in the Gilbert Archipelago 
although it is a part of the Gilbert and Ellice 
Islands Colony. Ocean Island is a higher island 
than the low atolls of the Gilberts, and has an 
annual average rainfall of 68 inches. It rises to 
265 ft, and beyond the fringing reefs drops 
abruptly to great depths. The fringing reef is 
rather different from those of the atolls, being 
composed in places of much rougher rocks; there 
are steep cliffs of very sharp weathered rock and 
few sandy beaches. There are, as on the atolls, 
deep surge channels in the edges of the reefs. 
There are deep pools on the reef flat, joined by 
tunnels in the reef, and living corals grow lux- 
uriantly in these more protected waters. There 
is a very large fish population, composed not 
only of reef dwellers, but also of oceanic and 
deepwater species. 
Ocean Island has large deposits of phosphates 
which have been worked since the early 1900s. 
Phosphate-loading vessels tie to moorings laid 
in very deep water. There is an old boat harbor 
with a wide deep passage through the reef on 
the western side which was blasted out of the 
reef in 1904. Since then a large new harbor has 
been built on the southeastern side, entailing 
extensive blasting of the reef. There is much 
cement and iron work on the reef, both in use 
and in the process of disintegrating from the old 
and new cantilever piers. 
All rubbish is thrown over a chute on these 
cliffs, to fall on the reef beneath; from there it 
is slowly washed away by high tides. Sewage is 
pumped out over the reef. The "Ocean Trader” 
was wrecked sometime ago on the southeast side, 
and was followed in 1952 by the "Kelvinbank,” 
which went on the reef on top of the remains 
of the previous vessel. The wrecks are still 
there, slowly disintegrating. During normal trade 
winds, blowing from the northeast through 
southeast, there is heavy surf on the eastern side 
of the island, but westerly weather is apt to 
cause heavy seas to beat all round the coast. 
In spite of all this reef damage extending back 
over 60 years, no poisonous fish have ever been 
reported from Ocean Island. 
Discussion 
Of the 16 islands in the Gilbert Island archi- 
pelago, 10 have toxic reefs where certain species 
of fish have been poisonous for varying lengths 
of time. These "toxic” islands are Tarawa, Abe- 
mama, Arunuka, Tabiteuea, Beru, Nonouti, and 
Onotoa, lagoon islands, and Nikunau, a reef 
island, on all of which some fish have been toxic 
for many years; on Butaritari and Marakei, toxic 
Fig. 11 . Map of Onotoa. 
