Citric Acid Injections: An Accessible and Efficient Method for Controlling Outbreaks of the Crown-of-Thorns Starfish Acanthaster cf. solaris

Abstract

Outbreaks of the crown-of-thorns starfish (Acanthaster cf. solaris, COTS) are one of the primary causes of coral decline in the Indo-Pacific region. Effective methods to control COTS outbreaks may therefore be one of the most direct and immediate ways to reduce coral loss. However, the cost and logistical challenges associated with current control methods have undermined the effectiveness of many control efforts. In this study, we tested the feasibility of using powdered citric acid, which is widely available and low-cost, as an injection chemical for COTS control. We tested what combination of concentration, number of injections, volume, and water type were most efficient at killing COTS. All COTS injected in two or four sites died, irrespectively of the concentration of citric acid used, while single injections failed at reaching 100% mortality. The fastest combination was the injection of 150 g·L −1 citric acid solution in four injection sites (5 mL per site), which killed the starfish in 26.4 ± 4 h. These results suggest that injections of powdered citric acid are an effective, economical, and widely available alternative to current COTS control methods.

Thirty Years of Research on Crown-of-Thorns Starfish (1986–2016): Scientific Advances and Emerging Opportunities

“…solaris each year. Currently, the most efficient and accepted method for culling is to individually inject starfish with specific chemicals [37,179,245] that cause immediate and comprehensive mortality. Manual controls are very labor intensive, though the recent development of a single-injection method [246] has increased the efficiency of in-water culling programs by at least 250%.…”

“…This special issue (Biology, Ecology and Management of Crown-of-Thorns Starfish) reflects the latest resurgence in scientific interest and research on Acanthaster spp., unequivocally focused on better understanding the initiation and spread of outbreaks, as well as refining the capability and capacity for effective management. The papers presented in this special issue address: (i) environmental drivers of fertilization and early development [23,24]; (ii) larval nutrition, larval development and implications for the 'nutrient enrichment hypothesis' [25][26][27][28][29]; (iii) predation and implications for the 'predator removal hypothesis' [30][31][32]; (iv) factors influencing settlement [27,30]; (v) dispersal and genetics [33]; (vi) longevity, growth, and size-and-age relationship [34,35]; (vii) movement [36]; and (viii) control and management [16,37].…”

Persistent Gaps of Knowledge for Naming and Distinguishing Multiple Species of Crown-of-Thorns-Seastar in the Acanthaster planci Species Complex

“…However, the most recent publications on COTSs increasingly reflect the reception of the species complex and its implications (e.g., [18][19][20][21][22][23]). …”

30 Years of Research on Crown-of-thorns Starfish (1986-2016): Scientific Advances and Emerging Opportunities

“…This special issue (Biology, Ecology and Management of Crown-of-Thorns Starfish) reflects the latest resurgence in scientific interest and research on Acanthaster spp., unequivocally focused on better understanding the initiation and spread of outbreaks, as well as refining the capability and capacity for effective management. In all, the papers presented in this special issue address: i) environmental drivers of fertilization and early development (Allen et al 2017;Caballes et al 2017b); ii) larval nutrition, larval development and implications for the 'nutrient enrichment hypothesis ' (Nakajima et al 2016;Brodie et al 2017;Caballes et al 2017a;Mellin et al 2017;Pratchett et al 2017b); iii) predation and implications for the 'predator removal hypothesis ' (Cowan et al 2016a' (Cowan et al , 2017Messmer et al 2017); iv) factors influencing settlement (Cowan et al 2016a;Pratchett et al 2017b); v) dispersal and genetics ; vi) longevity, growth, and size-and-age relationship (Wilmes et al 2016;MacNeil et al 2017); vii) movement (Sigl and Laforsch 2016); and viii) control and management (Buck et al 2016;Nakamura et al 2016).Aside from ongoing research to address critical issues related to the effective management of CoTS outbreaks, there have also been some fundamentally new directions for CoTS research in the last decade, enabled by advances in research methods and analytical capabilities. Therefore, this review also considers some of the foremost new directions for CoTS research, related to i) systematics and biogeography, ii) genetic and genomic sampling, iii) ecological modelling and iv) projected effects of environmental change.…”

“…solaris each year. Currently, the most efficient and accepted method for culling is to individually inject starfish with specific chemicals (Rivera-Posada et al 2014b;Boström-Einarsson and Rivera-Posada 2015;Buck et al 2016) that cause immediate and comprehensive mortality. Manual controls are very labour intensive, though the recent development of a single-injection method (Rivera-Posada et al 2013) has increased the efficiency of in-water culling programs by at least 250%.…”