Are increased nutrient inputs responsible for more outbreaks of crown-of-thorns starfish? An appraisal of the evidence.
The cause(s) of primary outbreaks of the coral-eating crown-of-thorns starfish (Acanthaster planci) are still subject to scientific controversy. The possibility of primary outbreaks being linked to terrestrial runoff has been postulated a number of times, suggesting that enhanced nutrient supply is critical for enhanced A. planci larval development. This paper examines the evidence for such a cause, focussing particularly on the Great Barrier Reef (GBR). Nutrient discharges from rivers have increased at least four-fold in the central GBR over the last century, and concentrations of large phyto-plankton (>2 microm) of the inshore central GBR shelf in the wet season when A. planci larvae develop, is double that of other places and times. Larval development, growth and survival increase almost ten-fold with doubled concentrations of large phyto-plankton. This and other lines of evidence suggest that frequent A. planci outbreaks on the GBR may indeed be a result of increased nutrient delivery from the land.
Brodie
Jon
J
Australian Centre for Tropical Freshwater Research, James Cook University, Townsville 4811, Australia. jon.brodie@jcu.edu.au
Fabricius
Katharina
K
De'ath
Glenn
G
Okaji
Ken
K
D000818:Animals; D037421:Anthozoa; D003247:Conservation of Natural Resources; D017753:Ecosystem; D007814:Larva / Q000254:growth & development; D018977:Micronutrients / Q000032:analysis / Q000378:metabolism*; D010839:Phytoplankton / Q000254:growth & development; D011157:Population Dynamics; D011793:Queensland; D013215:Starfish / Q000254:growth & development*
D018977:Micronutrients