A reagent and method for efficiently killing long-spined sea stars in situ

Abstract

This invention discloses a highly efficient reagent and method for in-situ eradication of crown-of-thorns starfish. It involves injecting a soluble calcium salt solution into the crown-of-thorns starfish to kill it. This invention uses underwater injection of calcium chloride solution to kill crown-of-thorns starfish, achieving a 100% eradication efficiency within 48 hours. Compared to traditional injectable agents such as copper sulfate, sodium cholate, and sodium bisulfate, calcium chloride requires a lower dosage, is easier to prepare, and has lower environmental impact. Furthermore, compared to the currently promoted acetic acid, calcium chloride is more convenient to carry and safer to operate, making it suitable for field control of crown-of-thorns starfish.

Description

Technical Field

[0001] This invention belongs to the field of reef-building coral protection, specifically relating to a reagent and method for killing crown-of-thorns starfish. Background Technology

[0002] Crown-of-Thorns Starfish (CoTS, Acanthaster spp.) belongs to the phylum Echinodermata, class Asteroidea, and genus Acanthaster. It is commonly found in tropical coral reefs of the Indo-Pacific region, primarily feeding on reef-building corals. When populations experience large-scale outbreaks, predation significantly reduces the cover of living corals, causing the collapse of coral reef ecosystems (Kayal et al., 2012; Pratchett, 2010). It has been reported that the Great Barrier Reef in Australia, the world's largest and longest coral reef system, experienced a 50% decline in coral cover between 1985 and 2012, with 42% of the loss attributed to crown-of-thorns starfish outbreaks. Since the beginning of this century, two recorded outbreaks of crown-of-thorns starfish have caused severe damage to coral reefs in the South my country Sea. The first outbreak, which began in 2004, caused the coral reef coverage in the Xisha Islands to plummet from 60% to less than 10%, while the second outbreak, which began in 2018, inflicted fatal damage on recovering stony corals. Therefore, carrying out crown-of-thorns starfish control work is of great significance for the sustainable development of coral reef ecosystems.

[0003] Currently, the mainstream control measure for crown-of-thorns starfish outbreaks is manual underwater harvesting to remove individual starfish from the coral reef area for eradication. While this method can reduce the density of the outbreak population to a certain extent, it is time-consuming, labor-intensive, costly, and inefficient, and carries the risk of personnel being stung by the starfish's venomous spines. Therefore, researchers have developed underwater eradication methods, primarily through direct underwater injection of chemicals to kill the starfish in situ. Compared to manual harvesting, this significantly improves eradication efficiency and reduces operational risks. However, currently available chemicals, including copper sulfate, sodium cholate, sodium bisulfate, and acetic acid, all have negative impacts on the aquatic environment and coral reef organisms, and require large quantities, necessitating caution in practical application. Therefore, the development of environmentally friendly and highly effective eradication agents remains crucial. Based on this need, after numerous experiments, we have invented a highly effective and environmentally friendly reagent and method for eradicating crown-of-thorns starfish, which is expected to be applied to the control of adult crown-of-thorns starfish. Summary of the Invention

[0004] The purpose of this invention is to provide a reagent and method for efficiently killing crown-of-thorns starfish in situ, solving the problems of low control efficiency and environmentally unfriendly killing agents for crown-of-thorns starfish.

[0005] The first objective of this invention is to provide the application of soluble calcium salts in the killing of crown-of-thorns starfish.

[0006] The preferred application is that of calcium chloride in the preparation of agents for killing crown-of-thorns starfish.

[0007] The second objective of this invention is to provide a method for killing crown-of-thorns starfish, comprising the following steps:

[0008] A soluble calcium salt solution was injected into the body of the crown-of-thorns starfish to kill it.

[0009] The soluble calcium salt is preferably calcium chloride, calcium hydroxide, calcium sulfate, or calcium oxide, and more preferably calcium chloride;

[0010] The calcium chloride is preferably a calcium chloride solution with a concentration from 0.1 mol / L to saturation, and more preferably a calcium chloride solution with a concentration of 1.8 mol / L.

[0011] The dosage of the injected star anise is 0.1-10 ml per animal.

[0012] This invention utilizes underwater injection of calcium chloride solution to kill crown-of-thorns starfish. Within 1 hour, it causes swelling and reduced vitality on the dorsal side of the starfish; within 12 hours, its dorsal spines collapse and its tentacles lose vitality; within 24 hours, the dorsal spines fall off, tissue ulcerates, and the individual loses vitality; and within 48 hours, all tissues rot and the individual dies. Compared to traditional injectable agents such as copper sulfate, sodium cholate, and sodium bisulfate, calcium chloride requires a lower dosage, is easier to prepare, and has lower environmental impact. Furthermore, compared to the currently promoted acetic acid, calcium chloride is more convenient to carry and safer to operate, making it suitable for fieldwork. Attached Figure Description

[0013] Figure 1 The survival rate of starfish after injection with five different reagents;

[0014] Figure 2 This describes the survival status of crown-of-thorns starfish after injection with calcium chloride solution and aged vinegar. Detailed Implementation

[0015] The present invention will be described in detail below with reference to specific embodiments, but this is not intended to limit the present invention.

[0016] Example 1:

[0017] In early May 2024, adult crown-of-thorns starfish were harvested from the Qionghai sea area and temporarily held in 1m×1m×1m pools at a depth of 0.8m with flowing water and aeration for two weeks. Seven healthy crown-of-thorns starfish, weighing 105±14g, with a radial diameter of 20±0.53cm and 15±0.75 arms, were randomly selected. Based on the availability and price of reagents, five reagents were selected for underwater injection testing to kill crown-of-thorns starfish: white vinegar, aged vinegar, cooking wine, 0.82mol / L ferric citrate solution, and 1.8mol / L calcium chloride solution. Using disposable syringes, six starfish were injected with the five different reagents and natural seawater (as control group 2), with an injection dose of 10ml for each. Starfish that were not injected with any solution served as control group 1. Figure 1 As shown, at 10 minutes, starfish injected with calcium chloride solution exhibited epidermal swelling and decreased vitality; at 12 hours, they showed dorsal spine loss, broken wrists, epidermal ulceration, and spontaneous splitting; at 24 hours, the individual split into two parts, with most of the tissue ulcerated; and after 48 hours, the tissue was completely ulcerated, and the individual died. Starfish injected with aged vinegar showed epidermal swelling at 50 minutes; at 12 hours, they showed dorsal spine loss, broken wrists, and epidermal ulceration; at 24 hours, they showed spontaneous splitting and tissue ulceration; and after 48 hours, the tissue was completely ulcerated, and the individual died. Starfish injected with white vinegar showed dorsal spine loss, epidermal ulceration, and broken wrists at 24 hours, and a small number of tentacles remained viable at 48 hours. Starfish in other injection groups showed normal behavior throughout the experiment. Figure 1 ).

[0018] Example 2:

[0019] In mid-May 2024, adult crown-of-thorns starfish were harvested from the Qionghai sea area and temporarily held in 1m×1m×1m pools at a depth of 0.8m with flowing water and aeration for two weeks. Sixteen healthy crown-of-thorns starfish were randomly selected, with a weight of 92±17g, a radial diameter of 19±1.65cm, and 14±1.15 arms. Based on the results of Example 1, calcium chloride and aged vinegar were used for further underwater injection to test the effectiveness of killing crown-of-thorns starfish. The concentration of calcium chloride solution used was 1.8mol / L, dissolved and mixed at room temperature. The naturally filtered seawater injection group served as control group 2, and the starfish without any injection served as control group 1. This experiment consisted of 4 groups, with 4 replicates per group, using a total of 16 starfish. Sixteen starfish were injected with calcium chloride solution, aged vinegar, and naturally filtered seawater using disposable syringes, with an injection volume of 10 ml for each. Four starfish served as a control group, receiving no injections. At 20 minutes, the four starfish injected with calcium chloride solution showed epidermal swelling and decreased activity. After 12 hours, their dorsal spines fell off, and their epidermis began to ulcerate. After 24 hours, most of their tissue ulcerated, and they lost activity. After 48 hours, their tissue completely ulcerated, and the starfish died. The four starfish injected with aged vinegar showed decreased activity 20 minutes after injection, followed by dorsal spine loss and epidermal ulceration after 12 hours. After 24 hours, their tissue ulcerated, and after 48 hours, their tissue completely ulcerated, and the starfish died. The starfish in the seawater injection and non-injection groups remained normal, healthy, and active throughout the experiment. Figure 2 ).

Claims

1. A method for killing crown-of-thorns starfish, characterized in that, Includes the following steps: A calcium chloride solution is injected into the body of the crown-of-thorns starfish to kill it. The calcium chloride is a 1.8 mol / L calcium chloride solution. The dosage injected into the body of the crown-of-thorns starfish is 0.1-10 ml per starfish.

Images