POPULATION EXPLOSIONS OF Acanthaster planci AND ASSOCIATED DESTRUCTION OF HERMATYPIC CORALS IN THE INDO-WEST PACIFIC REGION

Coral communities on many reefs of the central third of Australia's Great Barrier Reef have been subject to major damage by population outbreaks of the crown-of-thorns starfish Acanthaster planci twice since the 1960's. The interval between outbreaks on individual reefs was approximately 15 yr. This study compares size and damage frequency distributions of major taxa of scleractinian reef corals of massive morphology on 2 sets of 6 reefs of this region. One set of reefs had experienced major populahon outbreaks of A. planci, one set had not. All major reef types found in the area were represented in the sets which spanned 3 degrees of latitude. On both reef sets, representatives of the families Faviidae, Pontidae and Mussidae comprised ca 90 % of the massive corals present. However, the relative proportions of these taxa differed markedly between the 2 reef sets, with members of the Faviidae predominant on non-outbreak reefs and members of the Poritidae predominant on outbreakaffected reefs. Massive coral assemblages on outbreak reefs possessed only % the colonies on unaffected reefs and approximately half the surviving corals on the outbreak reefs exhibited damage of > 1/3 their colony surface areas. Few large (old) colonies occurred on the outbreak reefs, whereas such large corals were common on unaffected reefs. As most massive corals are slow-growing, long-lived and have lower rates of recruitment than corals of other morphology, continuing starfish reinfestation coincident with reestablishment of a coral cover by the faster-growing, more opportunistic corals will not allow sufficient time for recovery of the massive coral assemblages. They wlll be replaced by algae and non-masslve coral assemblages in the intervals between outbreaks. The recent devastating outbreaks appear to be abnormal perturbahons colncldent with large-scale human activities on the Great Barrier Reef, rather than integral features of reef ecology.

Section: -L0mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Predation on massive corals: are devastating population outbreaks of Acanthaster planci novel events9

Cameron¹,

Endean²,

DeVantier³

1991

“…The biological and physical environments of the infested reefs changed strikingly after predation by the starfish (e.g., Endean 1973, Hutchings 1986. Such widespread and intense reef degradation had significant effects on the structure of reef fish assemblages in some locations (Sano et al 1984a.…”

Section: Introductionmentioning

confidence: 99%

Stability of reef fish assemblages:responses to coral recovery after catastrophic predation by Acanthaster planci

Sano¹

2000

ABSTRACT. A long-term monitonng study was conducted at Inomote Island (Ryukyu Islands, Japan) to explore the responses of a disturbed adult fish assernblage to the recovery of coral on a large reef degraded by an outbreak of the coral-feeding starfish Acanthaster planci. In 1987, 5 yr after the outbreak, I censused a reef in which aii of the arborescent corals had been broken apart and the reef formation changed into a flat plain of unstructured rubble. Species nchness and numencal density of fishes on the dead reef had decreased severely. Natural recovery of the dead reef was mitiated mainly by larval recruitment of branching Acropora corals in 1989. Since that time, fish species nchness and density on the recovering reef have increased steadily with the increasing percentage cover of live corals. In 1995 to 1997, when the reef had almost 100% live coral cover, most fish assemblage properties (e.g., species numbers and abundances of the collective assemblage and component ecological groups) on the reef did not differ significantly from those on a nearby reef consisting mostly of arborescent Acropora. which had not suffered A. planci predation. The sirnilanty index indicated about 90% resemblance in species composition of the fish assernblages on the recovered and undisturbed reefs. These results demonstrate that the structure of the disturbed fish assemblage had returned to its preperturbation state on the near-completion of coral recovery.

“…Hermatypic corals of many reefs have been killed extensively by the starfish, and the biological and physical environment of infested reefs has changed drastically (e.g. Endean 1973, Nishlhira & Yamazato 1974. After attack by A. planci, the skeletons of corals become coated with tufts of various filamentous algae, and after a few years the exposed skeletons of branching corals collapse due to biological and physical erosion (review by Hutchings 1986).…”

Section: Introductionmentioning

confidence: 99%

Long-term effects of destruction of hermatypic corals by Acanthaster plana infestation on reef fish communities at Iriomote Island, Japan

Sano¹,

Shimizu²,

Nose³

1987

174

128

Long-term changes in structure of fish communities on coral reefs infested by the coralfeeding starfish Acanthasterplanci were determined using 20 mZ visual transects. We censused a living coral reef consisting mainly of staghorn Acropora spp. at Saluyama Bay and a dead coral reef with low structural complexlty of coral branches (about 2 yr after A. planci infestation) at Amitori Bay, Iriomote Island (Ryukyu Islands, Japan) in September 1984. Two yr later, we recensused the dead coral reef, which had changed into a flat plain of unstructured coral rubble ('rubble reef'). Mean numbers of species and individuals per transect severely decreased in the following order of reef types: (1) living reef (1984). (2) dead reef (1984), and (3) rubble reef (1986). Correlated with these decreases in numbers were several patterns: (1) coral-polyp feeders completely &sappeared on both dead and rubble reefs, probably due to absence of food; (2) numbers of resident species and individuals decreased on the dead reef, perhaps due to decrease in living space or shelter associated with the reduction in structural complexity of coral branches; and (3) numbers of species and individuals of both resident and visitor fishes declined on the unstructured rubble reef, likely due to shortage of living space and food.