The Acanthaster phenomenon /

Abstract

on the basis of it findings, that A. planci did not "constitute a threat to the Great Barrier Reef as a whole" (Walsh et al., 1971: p. 6). The conclusions of that committee, particularly the one just mentioned, were challenged and debated (e.g. Dwyer, 1971; Endean, 1971b; Talbot, 1971; O'Gower et al., 1972; James, 1976). During 1971 an advisory committee was established to implement the policies of the second committee of inquiry and to coordinate future research. Over the ensuing years many aspects of the biology of A. planci were studied. The progress of these studies was reported in a document prepared by the advisory committee (Walsh, Harvey, Maxwell & Thomson, 1976) and in it further research was recommended particularly on the ecology and population dynamics of the starfish and its coral prey. With the decline of starfish outbreaks during the latter half of the 1970s research on A. planci waned. A further committee was established (by the Great Barrier Reef Marine Park Authority) not long P. J. MORAN after a second outbreak was reported at Green Island at the end of 1979. Once again the results of previous research were reviewed and the significance of those outbreaks was assessed to determine whether further research was warranted. That committee considered the situation serious enough to recommend that several types of research be undertaken, addressing a number of broad aspects of the phenomenon (Advisory Committee on the Crown of Thorns Starfish, 1980). Some of this research was implemented although field studies on the ecology of the starfish were largely neglected. In view of the seriousness of the current series of outbreaks on the Great Barrier Reef another committee was formed with similar aims to those preceding it (Crown of Thorns Starfish Advisory Committee, 1985). In constrast to the findings of the second committee of inquiry this committee concluded that "the destruction of hard coral by aggregations of A. planci poses a serious threat to the organisation and functional relationships within some reef communities within the Great Barrier Reef, at least in the short term" (loc. at., p. 1). It also recognized that outbreaks of starfish posed a "major management problem in some areas of the Great Barrier Reef" (loc. cit., p. 1). On the basis of its findings the committee recommended that a coordinated programme of research be conducted over five years at an estimated cost of $A 3 million. Despite the reviews of these committees and the impetus that they gave to research they have not managed to quell the questions and debates, in Australia at least, concerning the phenomenon. Frequently the debate surrounding the occurrence of outbreaks has been reduced to whether they are seen to be a problem, or threat to the reef and, ultimately, whether they are natural or man-induced events. Logic would have it that if they are natural then nothing is required except to adopt sensible management in areas of commercial interest. If unnatural then action may be required. Reducing the debate to this simplistic ...

Contrasting ecological implications of food limitation in sea urchins and herbivorous gastropods

“…Asteroids are commonly found at high densities and can have a great impact on their environment (Paine 1969, Sloan 1980. For example, the large asteroid Acanthaster planci is often found in dense aggregations and can increase in density to populations of sufficient magnitude to earn the appellation 'outbreaks' (see Potts 1981, Moran 1986 for reviews). The devastating effect this species can, and does, have on coral communities throughout the tropical Indo-Pacific region has resulted in a continuing controversy concerning the processes that regulate the abundance of A. planci (see Potts 1981, Moran 1986.…”

Use of Oil and Gas Platforms as Habitat in Louisiana's Artificial Reef Program

“…It is well documented that oil and gas platforms function well as artificial reefs by providing habitat for a variety of species that are otherwise associated only with coral reefs, since many of these species are habitat-limited (Moran, 1986;Parrish, 1987;Sale, 1991). This is further emphasized by the fact that over 70% of all recreational angler trips in the Exclusive Economic Zone in Louisiana are destined for one or more of these structures (Reggio, 1987).…”

Pedicellariae of the crown-of-thorns sea star Acanthaster planci are not an effective defence against fouling

“…Nevertheless, the pedicellariae of A. planci may still have a limited protective role against small predators. Several species have been observed to feed on juvenile and adult A. planci, including the giant triton shell Charonia tritonis, the white-spotted pufferfish Arothron hispidus, 2 species of triggerfish Balistoides viridescens and Pseudobalistes flavimarginatus, 2 species of shrimp Hymenocera picta and Neaxius glyptocerus and the fire worm Pherecardia striata (reviewed by Moran 1986). Some predators may be smaller than A. planci and be able to move between the venomous spines without being affected by them.…”