Wolfe Kennedy, Graba-Landry Alexia, Dworjanyn Symon A, Byrne Maria
School of Medical Sciences, The University of Sydney, NSW 2006, Australia.
ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4811, Australia.
Mar Pollut Bull. 2017 Mar 15;116(1-2):307-314. doi: 10.1016/j.marpolbul.2016.12.079. Epub 2017 Jan 14.
Crown-of-thorns starfish, Acanthaster planci (COTS), predation is a major cause of coral reef decline, but the factors behind their population outbreaks remain unclear. Increased phytoplankton food resulting from eutrophication is suggested to enhance larval survival. We addressed the hypothesis that larval success is associated with particular chl-a levels in tightly controlled larval:algal conditions. We used chl-a conditions found on coral reefs (0.1-5.0μgchl-aL), including nominal threshold levels for disproportionate larval success (≥1.0μgchl-aL). High success to the juvenile occurred across an order of magnitude of chl-a concentrations (0.5-5.0μgchl-aL), suggesting there may not be a narrow value for optimal success. Oligotrophic conditions (0.1μgchl-aL) appeared to be a critical limit. With a review of the evidence, we suggest that opportunistic COTS larvae may be more resilient to low food levels than previously appreciated. Initiation of outbreak populations need not require eutrophic conditions.
棘冠海星（Acanthaster planci，COTS）的捕食是珊瑚礁衰退的主要原因，但其种群爆发背后的因素仍不清楚。有人认为，富营养化导致浮游植物食物增加会提高幼体存活率。我们探讨了这样一种假设，即在严格控制的幼体与藻类条件下，幼体的成功与特定的叶绿素a水平有关。我们采用了在珊瑚礁上发现的叶绿素a条件（0.1 - 5.0μg叶绿素a/升），包括幼体成功比例失调的名义阈值水平（≥1.0μg叶绿素a/升）。在一个数量级的叶绿素a浓度（0.5 - 5.0μg叶绿素a/升）范围内，幼体发育为幼鱼的成功率都很高，这表明可能不存在一个狭窄的最佳成功值。贫营养条件（0.1μg叶绿素a/升）似乎是一个关键限制。通过对证据的回顾，我们认为机会主义的棘冠海星幼体可能比之前认为的更能适应低食物水平。爆发种群的出现不一定需要富营养条件。
