they're harmless!

Another report on the starfish — they're harmless!

The academic argument over the crown of thorns starfish, which has been blamed with

everything from destroying reefs

to endangering the fishing sup

plies of the Pacific, continues,

from one extreme to another.

We started our reports with a paper by Dr. Endean that the crown of thorns was present in the Pacific in plague proportions and that it was a destroyer of vital reef structure.

Then came reports from geological authorities that the starfish was a cyclic menace and that it would go away when Mother Nature said so.

Then starfish researcher, Theo Brown, supported Dr. Endean and went even further. Now the Pennsylvania State University in the US has bought out its report.

The team came to the conclusion that the “abundance of this animal has been understimated in the past” because it was difficult to recognise, and moved only at night.

Isolated plagues

Recent plagues were “isolated, apparently unrelated, local, popula tion explosions, the timing of which may have been coincidental. . . .

The publicity given to the current outbreaks has raised considerable concern in the Pacific, but the fear that coral reefs face imminent ex tinction is not justified”.

The university, with members of the Marine Sciences Laboratory, Memorial University, Canada, carried out observations in 13 areas of the Pacific over a period of 500 man

days exploration, stretched over three years up to 1969.

They found on the Great Barrier Reef, infestation was restricted to only 40 of the 1,000 reefs. On the south-east coast of Vitu Levu it was conspicuous among dead coral, and this was interpreted as a response by the starfish to a drastic reduction of its food supply following mass killing of the reefs during the 1964-65 fresh water flooding. It appeared that the prevalence of starfish had been underestimated in the past because of their preference to lagoon slopes.

Where they were seen

From Papua-New Guinea to the Solomon Islands, very few starfish were sighted. In the northern Gilberts there were both starfish and dead coral—but the team came to the conclusion that the two were not con nected. In French Polynesia, the team found that the few starfish encountered, tended to move about and select coral heads rather than devour indiscriminantly any coral lying in their path.

A full report on the survey is shortly to appear in Marine Biology.

The paper is by J. N. Weber and P.

M. J. Woodhead, entitled “Ecological studies of the coral predator Acan thaster planci in the South Pacific”.

Jon Weber is Associate Professor, Department of Geology and Geo physics, Pennsylvania State University.

Meanwhile it’s reported German scientists have discovered a prawn which attacks and destroys the star fish. Sample starfish are being flown from Australia as “guinea-pigs” for the prawns.

• How serious really is the threat to Pacific coral reefs by the crown of thorns starfish? We've been told that reefs like this one, protecting Aitutaki atoll, in the Cook Islands, and its important airstrip, can disappear under the starfish attack. But another recent report, discussed on this page, now says that the starfish problem has been exaggerated.