Acanthaster Planci Research Articles

Genomic Single Nucleotide Polymorphism (SNP) markers and mitochondrial haplotypes illuminate the origins of Crown-of-Thorns Starfish (Acanthaster solaris) outbreaks in the South China Sea.

Outbreaks of the coral predator Crown-of-Thorns Starfish (CoTS) pose a severe threat to coral reefs in the Indo-Pacific Ocean. In 2018, the South China Sea (SCS) experienced significant CoTS outbreaks, leading to extensive coral mortality across the Xisha, Zhongsha, Dongsha, and Nansha Islands, severely impacting the coral reef ecosystem. To explore the origins of these outbreaks, we conducted a comprehensive genomic analysis using data from genomic single nucleotide polymorphism sites (SNPs) and mitochondrial haplotypes. Our analysis reveals that CoTS populations in the SCS, which exhibit moderate genetic diversity and may have undergone positive selection or population expansion. There was limited genetic differentiation among CoTS populations from XS, ZS, and NS groups. Especially between the XS and ZS groups, there was almost no genetic differentiation. The populations from XS, ZS, and NS groups have strong genetic connections with populations in Vietnam and the Philippines. There was high gene flow from Vietnam to the Xisha Islands and from the Philippines to the Nansha Islands, suggesting that the CoTS populations in these regions primarily originate from these neighboring countries. The comprehensive analyses of SNP and mitochondrial genomes have provided valuable insights into the population genetics of CoTS. This research has generated significant genomic resources and facilitated important studies on the genetics of the CoTS species. By identifying potential source populations and understanding the genetic basis of their spread, managers can develop more effective conservation strategies to protect vulnerable coral reef ecosystems in the SCS.

Quantifying public support for culling crown‐of‐thorns starfish (Acanthaster spp.) on the Great Barrier Reef

AbstractPopulation surges of crown‐of‐thorns starfish (COTS) (Acanthaster spp.) are a leading cause of coral cover loss on Australia's Great Barrier Reef (GBR). While COTS culling has been undertaken since 2012 little is known about how the public perceive COTS culling or how perceptions vary among social groups. Drawing on survey data collected in 2018 and 2022 we test the relative influence of demographic variables, social and institutional variables, and beliefs concerning the risks and benefits of culling, on public acceptance for the culling of COTS on the GBR. In contrast with previous research suggesting a polarization of views, we found limited opposition to culling (12% in 2018 and 8% in 2022). Remaining respondents, however, were almost equally divided between those who agreed or strongly agreed with culling and those who were neutral or only slightly in agreement. The strongest predictors of support, in terms of standardized mean odds ratios, were the perceived social, environmental, and ethical responsibility of culling (1.57), the manageability of culling risks (1.46), the personal importance of the GBR to the respondent (1.33), trust in science to deliver solutions (1.30), confidence in management of the GBR (1.26), and how much of a threat respondents believed COTS posed to the Reef (1.25). These findings suggest public communications about COTS culling might usefully focus on how scientific understanding, ongoing research, ecosystem monitoring, and partnerships with Reef Traditional Owners and stakeholders guide operations.

Vinegar injections can be used safely to control outbreaks of crown-of-thorns starfish Acanthaster cf. solaris during the peak spawning season

Concerns are mounting over the effects of crown-of-thorns starfish (COTS) (Acanthasteridae) outbreaks, prompting the need for integrated management strategies. Although direct control methods are short-term and localized, they remain one of the few operational tools that can be easily implemented by locals. Vinegar injections have recently emerged as a highly effective method; however, their impact on reproductive behavior remains untested. Here, we investigated the short-term spawning response of mature COTS to double injections of household vinegar. First, COTS abundances and reproductive status were monitored during a massive outbreak affecting New Caledonia’s reefs. In situ and laboratory experiments were then conducted to determine whether injected COTS would trigger synchronized spawning among mature individuals in close proximity. Our results indicated that injections had no significant effect on spawning behavior, even in densely populated aggregations (>4000 COTS ha-1). In the field, starfish exhibited ripe gonads with high gamete content (up to 35% of body weight) 3 d after conspecifics were injected. In the laboratory, mature COTS that were held with injected, decaying individuals in a confined volume did not expel their gametes after 2 d. This suggests that vinegar injections could be used at any time, even during peak spawning, without risking synchronized spawning in the affected areas.

Crown-of-thorns starfish complete their larval phase eating only nitrogen-fixing Trichodesmium cyanobacteria.

Cyanobacteria of the genus Trichodesmium form extensive blooms that supply new N to nutrient-poor marine ecosystems. Yet little is known about what eats Trichodesmium. In this laboratory study, we show that one of the greatest threats to coral reefs, predatory crown-of-thorns starfish (CoTS), Acanthaster sp., completes their larval phase feeding solely on Trichodesmium. We observed Trichodesmium erythraeum CMP1985 in the stomachs of larvae using florescence microscopy and traced the assimilation of nitrogen from labeled trichomes into larval tissues using stable isotopes. Some larvae fed T. erythraeum were morphologically ready to become benthic juveniles after 19 days. Given that Trichodesmium can be food for CoTS, reported increases in Trichodesmium could be a driving factor in the heightened frequency of CoTS population irruptions that have devastated coral reefs in past decades. Future studies could test this through investigating the diets of wild larvae and incorporating Trichodesmium abundance into models of CoTS population dynamics.

Beyond texture: unveiling spiny crown-of-thorns starfish with multiresolution analysis

Coral reefs are essential ecosystems in the vast expanses of oceans, nurturing various forms of marine life within their vibrant and expansive structures. However, these underwater paradises suffer considerable threat from the population explosions of crown-of-thorns starfish (COTS), which detrimentally affect scleractinian corals across the Indo-Pacific region. This study addresses the early drawback of solely relying on texture analysis for COTS detection, recognizing the associated insufficiency due to variability in reef substrates. By integrating multiresolution analysis employing wavelet transform, edge information, and texture analysis using gray-level co-occurrence probability, this approach employs crucial Haralick features refined for pattern recognition. This enables a more detailed understanding of COTS traits, including the detection of the numerous sharp spines that cover their upper bodies. This approach considerably enhances classification reliability, making notable progress with an impressive accuracy of 95.00% using the eXtreme Gradient Boosting (XGBoost) Classifier. Moreover, this model streamlines processing requirements by increasing computational and memory efficiencies, making it more resource-efficient than the current models. This advancement enhances detection and opens avenues for early intervention and future research. Furthermore, integrating the model with underwater imagery could enable citizen science initiatives and autonomous underwater vehicle (AUV) surveys. Empowering trained volunteers and equipping AUVs with this technology could considerably expand coral reef monitoring efforts. Early COTS outbreak detection allows for shorter response times, potentially mitigating the damage and facilitating targeted conservation strategies.

Seasonal tissue-specific gene expression in wild crown-of-thorns starfish reveals reproductive and stress-related transcriptional systems.

Animals are influenced by the season, yet we know little about the changes that occur in most species throughout the year. This is particularly true in tropical marine animals that experience relatively small annual temperature and daylight changes. Like many coral reef inhabitants, the crown-of-thorns starfish (COTS), well known as a notorious consumer of corals and destroyer of coral reefs, reproduces exclusively in the summer. By comparing gene expression in 7 somatic tissues procured from wild COTS sampled on the Great Barrier Reef, we identified more than 2,000 protein-coding genes that change significantly between summer and winter. COTS genes that appear to mediate conspecific communication, including both signalling factors released into the surrounding sea water and cell surface receptors, are up-regulated in external secretory and sensory tissues in the summer, often in a sex-specific manner. Sexually dimorphic gene expression appears to be underpinned by sex- and season-specific transcription factors (TFs) and gene regulatory programs. There are over 100 TFs that are seasonally expressed, 87% of which are significantly up-regulated in the summer. Six nuclear receptors are up-regulated in all tissues in the summer, suggesting that systemic seasonal changes are hormonally controlled, as in vertebrates. Unexpectedly, there is a suite of stress-related chaperone proteins and TFs, including HIFa, ATF3, C/EBP, CREB, and NF-κB, that are uniquely and widely co-expressed in gravid females. The up-regulation of these stress proteins in the summer suggests the demands of oogenesis in this highly fecund starfish affects protein stability and turnover in somatic cells. Together, these circannual changes in gene expression provide novel insights into seasonal changes in this coral reef pest and have the potential to identify vulnerabilities for targeted biocontrol.

DNA metabarcoding as a tool for characterising the spatio-temporal distribution of planktonic larvae in the phylum Echinodermata

AbstractMetabarcoding is revolutionising the analysis of biodiversity in marine ecosystems, especially as it provides a means of detecting and identifying cryptic life stages in field samples. The planktonic larval stage of many species underpins the abundance and distribution of adult populations but is challenging to characterise given the small size of larvae and diffuse distributions in pelagic waters. Yet, planktonic larval dynamics are key to understanding phenomena observed in adult populations, such as the boom-and-bust dynamics exhibited by some echinoderms. Rapid changes in echinoderm population density can have significant effects on local benthic ecosystems. For example, outbreaks of the crown-of-thorns sea star (CoTS) on the Great Barrier Reef (GBR) have led to considerable declines in coral cover. Here, we used a DNA metabarcoding approach to investigate the spatio-temporal distribution and diversity of echinoderm larvae on the GBR, including CoTS. Generalised linear mixed models revealed that echinoderm larval richness, was significantly correlated with temporal variables (i.e. season and year) which is consistent with expected fluctuations in larval output based on adult spawning periodicity. However, neither site-specific differences in echinoderm larval richness, nor correlations between larval composition and environmental, temporal, or spatial variables were found. This study validates the utility of metabarcoding approaches for detecting and characterising echinoderm larvae, including CoTS, which could prove useful to future monitoring efforts. Our findings suggest that metabarcoding can be used to better understand the life history of planktonic larvae, and analyses combining environmental (e.g., temperature, nutrients) and oceanographic (e.g., currents) data could deliver valuable information on the factors influencing their spatio-temporal distributions.

Action of Ergost-7-en-3- ol from (Acanthaster planci) stimulation of activity peritoneal macrophages

An is a compound capable of influencing the human immune system because it can maintain and restore the balance of the immune system by stimulating the immune system through phagocytosis, the complement system, IgA antibody secretion, the release of interferon α and γ, T and B lymphocytes, specific antibody systems, and cytokines. Immunomodulators can be obtained from natural sources, one of which is Acanthaster planci, which is one of the marine organisms that has important bioactive substances that can act as immunomodulators. The purpose of this research is to determine the immunomodulatory activity of chloroform fractions FrKl3.1.3.1 and FrKl3.1.3.2 and to identify the immunomodulatory compounds from the chloroform fraction FrKl3.1.3.1 of A. planci. The results of the study showed that the macrophage test of the FrKl3.1.3.1 fraction had higher activity compared to FrKl3.1.3.2, while the spectroscopic data analysis results showed that UV-VIS had a maximum absorption at a wavelength (λmax) of 240 nm, FTIR data (cm-1) showed the presence of hydroxyl (-OH) groups, alkene groups (double bonds (C=C)), and aliphatic C-H groups. The 1H-NMR data (CDCl3, 500 MHz) showed six methane groups, ten aliphatic methylene groups (-CH2-), nine geminal methylene groups, one methylene group with a double bond, and 13C-NMR and DEPT 135 data (CDCl3, 125 MHz) indicated that the A. planci FrKl3.1.3.1 fraction had 28 carbon atoms consisting of six methyl (-CH3) carbon atoms, ten methylene (-CH2) carbon atoms, and nine methine (-CH-) carbon atoms. From the spectroscopic analysis data, it is known that the chloroform fraction of A. planci FrKl3.1.3.1 is ergost-7-en-3-ol compound.

A new strategy based on a cascade amplification strategy biosensor for on-site eDNA detection and outbreak warning of crown-of-thorns starfish

Population outbreaks of the crown-of-thorns starfish (COTS) seriously threaten the sustainability of coral reef ecosystems. However, traditional ecological monitoring techniques cannot provide early warning before the outbreaks, thus preventing timely intervention. Therefore, there is an urgent need for a more accurate and faster technology to predict the outbreaks of COTS. In this work, we developed an electrochemical biosensor based on a programmed catalytic hairpin assembly (CHA) and hybridization chain reaction (HCR) cyclic amplification strategy for sensitive and selective detection of COTS environmental DNA (eDNA) in water bodies. This biosensor exhibited excellent electrochemical characteristics, including a low limit of detection (LOD = 18.4 fM), low limit of quantification (LOQ = 41.1 fM), and wide linear range (50 fM – 10 nM). The biosensing technology successfully allowed the detection of COTS eDNA in the aquarium environment, and the results also demonstrated a significant correlation between eDNA concentration and COTS number (r = 0.990; P < 0.001). The reliability and accuracy of the biosensor results have been further validated through comparison with digital droplet PCR (ddPCR). Moreover, the applicability and accuracy of the biosensor were reconfirmed in field tests at the COTS outbreak site in the South China Sea, which has shown potential application in dynamically monitoring the larvae before the COTS outbreak. Therefore, this efficient electrochemical biosensing technology offers a new solution for on-site monitoring and early warning of the COTS outbreak.

THREE-DECADE changes of reef cover in Pulau Layang-Layang, Malaysia using multitemporal Landsat images

Over the years, coral reefs in the South China Sea have degraded and faced severe threats from rapid development, coral bleaching, and Crown-of-Thorns Starfish (COTS) outbreak. There is limited knowledge relating to the effects of anthropogenic disturbances and natural events on the coral reefs of Pulau Layang-Layang. This study aims to assess reef cover changes by utilizing Landsat satellite images spanning from 1989 to 2022. Using the object-based image analysis method, this study classified the reef cover into three categories: coral, rock and rubble, and sand. The supervised classification had an overall accuracy of 86.41–87.38 % and Tau's coefficients of 0.80–0.81. The results showed island development and construction of artificial bird sanctuary have led to an increase in coral cover. Furthermore, it was illustrated that the impact of COTS outbreaks in 2010 and 2020 differed significantly, with the latter showing no signs of recovery. Our study underscores the importance of timely intervention to mitigate the spread of COTS. This study provides insights into the resilience and vulnerability of these ecosystems in the face of various stressors.

Stochastic dynamics of coral reef system with stage-structure for crown-of-thorns starfish

The outbreak of crown-of-thorns starfish (CoTS) is one of the most critical biological disturbances in coral reef systems and contributes greatly to the degradation of coral. Although many studies have focused on coral-CoTS interactions, there is no effective method for suppressing CoTS outbreaks in the long term, in part because of incomplete knowledge of their life cycle. In this paper, a stochastic system is formulated to characterize the interactions among coral, immature CoTS, and mature CoTS, where environmental noise is introduced into the growth of coral. The existence and uniqueness of a global positive solution with any given initial value are investigated, sufficient conditions are established for the extinction of CoTS, and the existence and uniqueness of a stable stationary distribution are explored by applying the Markov semigroup theory. In particular, by solving the Fokker–Planck equation, the approximate expression of the probability density function of the distribution around its quasi positive equilibrium is expounded under certain parametric restrictions. By employing Milstein’s higher-order method, numerical simulations are presented to validate the theoretical results. This study reveals that coral are more vulnerable and are more likely to go extinct in the presence of strong noise, while weak noise is more conducive to the existence of a stable stationary distribution, which implies the long-term persistence of coral and CoTS.

The crown-of-thorns starfish Acanthaster planci as a predator of black coral Antipathes galapagensis in the Gulf of California

We report observations of the crown-of-thorns starfish Acanthaster planci feeding on the black coral Antipathes galapagensis in the Gulf of California. Starfish individuals had diameters from 10 to 15 cm, showing two methods for feeding. Predation on black coral appears to be a response to the lack of alternative prey types.

Abundance Megabentos in Coral Reef Ecosystems in the Waters of Gelasa Island, Central Bangka Regency.

Megabenthos is a group of fauna that inhabits the benthic zone, which is the bottom or substrate of aquatic environments (both infauna and epifauna), with a body size exceeding 10 mm (1 cm). This study aims to analyze the abundance of megabenthos in the coral reef ecosystem, examine the relationship between megabenthos abundance and the physical and chemical parameters of the aquatic environment in the coral reef ecosystem, and analyze the relationship between megabenthos abundance and coral life forms in the waters of Gelasa Island. This research was conducted in September 2022 in the waters of Gelasa Island. Megabenthos data were collected using the Bentos Belt Transect (BBT) method, while coral data were collected using the Underwater Photo Transect (UPT) method. The study identified 10 species of megabenthos in the coral reef ecosystem of Gelasa Island. The species found at the research site include Diadema setosum, Diadema antillarium, Echinothrix calamaris, Drupella cornus, Drupella rugosa, Trochus conus, Tectus pyramis, Tridacna squamosa, Tridacna crocea, and Acanthaster planci. The percentage of live coral cover at the research site ranged from 26.60% to 71.00%. Megabenthos abundance was analyzed using Principal Component Analysis (PCA) to examine the relationship between megabenthos and the physical and chemical parameters of the aquatic environment and the relationship between megabenthos and coral life forms.

The Effects of Climate Change on Hawaii’s Coral Reef Ecosystem Over the Past 20 Years

The Hawaiian islands are known for their rich marine biodiversity in coral reef ecosystems. However, in the last 20 years, changes in sea surface temperatures, sea levels, carbon dioxide levels, and ocean pH have severely impacted these reef ecosystems. Hawaiian corals can experience heat stress with temperatures as little as 1-2 °C above the average and thermal stress events were prevalent from 2014-2017, causing bleaching and increasing mortality. The increase in sea level in Hawaiian marine ecosystems has caused reefs to “drown” from the lack of sufficient sunlight and thus suffer from bleaching. Coral disease is linked with high temperatures, seen through the common reef-building coral disease white syndrome. Invasive species outbreaks, with Acanthaster planci as an example, are also correlated with changes in the climate and reef communities. With the loss of coral, there have been consequences on marine biodiversity in Hawaiian reef ecosystems. Specifically, the three most native coral genera, porites, montipora, and pocillopora, which are the most important species to the reefs, have been declining in population. As a result, higher threat statuses have been observed among turtles, reef fish, and marine mammals that are reliant on their coral reef ecosystems for protection and food sources.

Distributed task allocation and mission planning of AUVs for persistent underwater ecological monitoring and preservation

This paper presents a robust cooperative distributed task allocation and mission planning system that enables a fleet of a certain class of autonomous underwater vehicles (AUVs) for persistent underwater ecological monitoring and preservation. The proposed system is developed based on a distributed algorithm that optimizes task allocation and mission planning in real-time while considering environmental constraints, sensor capabilities, communication limitations, as well as system failures. A realistic case study of monitoring and control of Crown-Of-Thorns Starfish (COTS) in Australia's Great Barrier is utilized to investigate how the proposed system can contribute to the inspection and eradication of the maximum possible COTS in a limited mission time in the exposure of uncertainty of mission failure caused by internal/external faults. The effectiveness and robustness of our approach are validated through extensive qualitative and quantitative simulations.

Cloning and functional characterization of the oxidative squalene cyclase gene in the deep-sea holothurian Chiridota sp.

Saponins derived from holothurians have high potential medicinal value. However, the de novo synthesis of the derivatization of triterpenes is still unclear. Oxidative squalene cyclase (OSC) can catalyze 2,3-Oxidosqualene into diverse products that serve as important precursors for triterpene synthesis. However, the function of theOSCgene in Chiridotasp. hasnot been elucidated. In this study, an OSCgenederived from the deep-sea holothurianChiridota sp. was cloned and characterized functionally in a yeast system. The open reading frame of the OSC gene was 2086 bp, which encoded 695 amino acids. The Chiridota sp. OSC gene has a similarity of 66.89 % to the OSC of other holothurian species and 63.51 % to that of Acanthaster planci. The phylogenetic tree showed that the echinozoan OSCsclustered together, and then they formeda sister group to fungi and plant homologs. Chiridota sp. OSC catalyzed 2,3-Oxidosqualene into parkeol.Under high pressure, the relative enzymatic activity and stability of cyclase inChiridota sp. was higher than that in the shallow-sea holothurianStichopus horrens. The newly cloned OSC of Chiridota sp.provideskey information for the interpretation of the saponin synthesis pathway in deep-sea holothurians.

Improving coral cover using an integrated pest management framework.

Integrated pest management (IPM) leverages our understanding of ecological interactions to mitigate the impact of pest species on economically and/or ecologically important assets. It has primarily been applied in terrestrial settings (e.g., agriculture), but has rarely been attempted for marine ecosystems. The crown-of-thorns starfish (CoTS), Acanthaster spp., is a voracious coral predator throughout the Indo-Pacific where it undergoes large population increases (irruptions), termed outbreaks. During outbreaks CoTS act as a pest species and can result in substantial coral loss. Contemporary management of CoTS on the Great Barrier Reef (GBR) adopts facets of the IPM paradigm to manage these outbreaks through strategic use of direct manual control (culling) of individuals in response to ecologically based target thresholds. There has, however, been limited quantitative analysis of how to optimize the implementation of such thresholds. Here we use a multispecies modeling approach to assess the performance of alternative CoTS management scenarios for improving coral cover trajectories. The scenarios examined varied in terms of their ecological threshold target, the sensitivity of the threshold, and the level of management resourcing. Our approach illustrates how to quantify multidimensional trade-offs in resourcing constraints, concurrent CoTS and coral population dynamics, the stringency of target thresholds, and the geographical scale of management outcomes (number of sites). We found strategies with low target density thresholds for CoTS (≤0.03 CoTS min-1 ) could act as "Effort Sinks" and limit the number of sites that could be effectively controlled, particularly under CoTS population outbreaks. This was because a handful of sites took longer to control, which meant other sites were not controlled. Higher density thresholds (e.g., 0.04-0.08 CoTS min-1 ), tuned to levels of coral cover, diluted resources among sites but were more robust to resourcing constraints and pest population dynamics. Our study highlights trade-off decisions when using an IPM framework and informs the implementation of threshold-based strategies on the GBR.

The effect of catchment load reductions on water quality in the crown-of-thorn starfish outbreak initiation zone

Crown-of-Thorns Starfish (CoTS) population outbreaks contribute to coral cover decline on Indo-Pacific reefs. On the Great Barrier Reef (GBR), enhanced catchment nutrient loads are hypothesised to increase phytoplankton food for CoTS larvae in the outbreak initiation zone. This study examines whether catchment load reductions will improve water quality in this zone during the larval period. We defined the i) initiation zone's spatial extent; ii) larval stage's temporal extent; and iii) water quality thresholds related to larval food, from published information. We applied these to model simulations, developed to quantify the effect of catchment load reductions on GBR water quality (Baird et al., 2021), and found a consistently weak response of chlorophyll-a, total organic nitrogen and large zooplankton concentrations in the initiation zone. Model results indicate marine and atmospheric forcing are more likely to control the planktonic biomass in this zone, even during major flooding events purported to precede CoTS outbreaks.

Branching coral growth and visual health during bleaching and recovery on the central Great Barrier Reef

Coral reefs are under threat from cumulative impacts such as cyclones, crown-of-thorns starfish (COTS) outbreaks and climate-driven coral bleaching events. Branching corals are more severely impacted by these events than other coral morphologies due to their sensitivity to heat stress and weaker skeletons and COTS preferred prey. The central Great Barrier Reef experienced unprecedented back-to-back bleaching events in 2016 and 2017. This study commenced in 2017 at the peak of heat stress and examined the impact of the heatwave on the survival and recovery of corals by assessing the growth, health (based on the visual health index) and physiological parameters (chlorophyll a, zooxanthellae density, lipid and protein content) of two species, Acropora millepora and Pocillopora acuta (N = 60 colonies for each species). It was conducted across a gradient of turbidity at three reefs, Pandora, Orpheus and Rib, that experienced in April 2017, degree heating weeks (DHW) of 9, 8 and 7, respectively. Orpheus experienced the worst bleaching, based on visual health score, followed by Rib and Pandora. Rib experienced the greatest mortality (78% by Nov 2017); however, this was attributed to the presence of actively feeding crown-of-thorns starfish. Growth rates of A. millepora were almost twice the rate of P. acuta. Both species showed significant seasonal variation with growth of A. millepora and P. acuta 35–40% and 23–33% significantly greater in the summer, respectively. Differences in growth rates were best explained by indicators of energy acquisition. For example, the most important predictor variable in determining higher growth rates and visual health score in A. millepora was chlorophyll a content. For P. acuta, visual health score was the best predictor variable for higher growth rates. This study highlights the important role that chlorophyll a and associated symbionts play in growth and survival in these corals during and after a heat stress event.

A FRAMEWORK FOR COOPERATIVE DYNAMIC TASK ASSESSMENT FOR COTSBOT AUVs

ABSTRACT-This project presents a proposed framework aimed at collaborative and dynamic allocation of tasks for a specific group of self- governing underwater vehicles known as autonomous underwater vehicles (AUVs). These AUVs are utilized to manage the proliferation of Crown-Of-Thorns starfish (COTS) on the Great Barrier Reef situated in Australia. The concept of constrained task allocation is employed to reframe the supervision and regulation of COTS into a challenge where a central task involves eradicating clusters of COTS using the injection mechanism integrated into the COTSbot AUVs. The operational setting, encompassing underwater topography, COTS clusters, and shorelines, is mapped probabilistically. The COTSbot AUVs are then collaboratively deployed to target as many COTS clusters as possible within a designated mission timeframe, utilizing an inventive heuristic technique termed Heuristic Fleet Cooperation (HFC). To substantiate the efficiency and dependability of the proposed collaborative task allocation algorithm for COTS eradication in the Great Barrier Reef, comprehensive simulations and quantitative performance evaluations are conducted.