Method for removing filamentous algae infecting hydranth

Abstract

The invention discloses a method for removing filamentous algae infecting hydranths. The method comprises the following steps: (1) preparing copper ion-containing seawater with the concentration of 100-250 [mu] g / L by using artificial seawater as a solvent; (2) preparing bait to culture hydranths; (3) culturing the hydranth infected by the filamentous algae by using the prepared seawater containing the copper ions to remove the filamentous algae, replacing the seawater containing the copper ions once every 2-3 days in the period to maintain the concentration of the copper ions, and at the moment, degenerating the hydranth to form hydranth dormant bodies; (4) after the filamentous algae are completely removed, replacing the filamentous algae with normal seawater, and enabling the hydranth population to enter a recovery period; in the recovery period, the filamentous algae do not appear again, new hydranths grow out of the hydranth dormant bodies after 1-16 days, and then the hydranths return to normal. By utilizing the method provided by the invention, the filamentous algae infecting the hydranth can be effectively removed, the hydranth can be quickly recovered into a healthy hydranth group in normal seawater after being treated by the copper ions, and healthy jellyfish bodies can be continuously formed and released.

Description

Technical Field

[0001] The invention belongs to the technical field of germplasm resource preservation, and in particular relates to a method for removing filamentous algae infecting polyps. Background Art

[0002] Cnidaria only have endoderm and ectoderm, and their bodies are radially symmetrical. They mainly include jellyfish, corals and other groups, and occupy a unique position in the process of life evolution. Among them, jellyfish are the cnidarians with the highest biodiversity and the richest life history types, and their research value is very high.

[0003] Cladonema, Clytia and Cassiopea all belong to the phylum Cnidaria, and all have two typical stages: polyp and medusa, with alternation of generations in their life history. Among them, Cladonema pacificum and Cladonema radiatum have become model organisms in the fields of development, regeneration and other biological and physiological research, and are mainly used in the study of development, regeneration, branching of organism structure, eye spot formation, and the cellular and molecular mechanisms of starvation. Clytia hemisphaerica has been used as a model organism in the study of neural development, cell differentiation, evolution and other aspects. Cassiopea is a common species of jellyfish exhibited in aquariums and has high ornamental and research value. Among them, Cassiopea andromeda and Cassiopea xamachana have been used as model organisms for research on symbiosis, regeneration, and neural development.

[0004] Species such as the finger-shaped branch-hand jellyfish, the flying white branch-hand jellyfish, the Xiamen beautiful jellyfish, and the Andros jellyfish are easy to raise and have strong regeneration capabilities, making them good experimental organisms. However, in a laboratory environment, the polyp colonies of the branch-hand jellyfish are easily squeezed out of their living space by the invading filamentous algae, which eventually leads to death. Filamentous algae adhere to the polyps, and it is necessary to manually pick out uninfected polyps regularly and re-expand them to obtain healthy and clean polyp colonies, which is a lot of work. In addition, filamentous algae can also infect the polyp colonies of various jellyfish such as the Xiamen beautiful jellyfish and the Andros jellyfish, causing certain damage. Therefore, there is an urgent need for a simple and effective algae removal method to maintain the normal growth of the polyps.

[0005] Copper is a cost-effective algaecide. Copper sulfate and copper-containing algaecides are broad-spectrum fungicides and algaecides. Due to their high efficiency and low cost, they have been commonly used to control phytoplankton blooms in ponds, aquaculture waters, reservoirs and other areas for decades. In addition to phytoplankton, copper sulfate affects the growth of filamentous algae of Spirogyra, Algae and Tribonella. The 72h-EC 50 The copper-containing algaecide has a good inhibitory effect on large algae such as Nitellopsis obtusa. Among the many copper-containing algaecides, copper sulfate (copper ion) has a low cost and obvious algae removal effect. Copper is an essential trace element for life, but excessive copper can cause harm to organisms. At present, the research on the effect of copper ions on cnidarians is mainly focused on corals, anemones and other organisms of the class Anthozoa, and there is less research on jellyfish groups such as Hydrozoa and Scyphozoa. Summary of the invention

[0006] In order to solve the problems existing in the prior art, the present invention provides a method for removing filamentous algae infecting polyps, which is suitable for polyps that can tolerate the stress of a certain concentration of copper ions. It can not only effectively remove the filamentous algae infecting the polyps, but also the polyps can quickly recover into healthy hydra groups in normal seawater after being treated with copper ions, and continue to form and release healthy jellyfish.

[0007] The technical solution of the present invention is as follows:

[0008] The present invention provides a method for removing filamentous algae infecting polyps, comprising the following steps:

[0009] (1) using seawater as a solvent to prepare seawater containing copper ions, wherein the copper ion concentration is 100 to 250 μg / L;

[0010] (2) preparing food for feeding polyps;

[0011] (3) using the copper ion-containing seawater with a concentration of 100 to 250 μg / L prepared in step (1) to cultivate polyps infected by filamentous algae to remove the filamentous algae, and replacing the copper ion-containing seawater every 2 to 3 days to maintain the copper ion concentration;

[0012] (4) After the filamentous algae are completely removed and replaced with normal seawater, the hydra colony enters a recovery period; during the recovery period, the filamentous algae do not reappear, and the dormant hydra grows new hydras after 1 to 16 days.

[0013] Furthermore, in step (1), seawater with a salinity of 30 to 35 ppt is prepared using seawater element and pure water, and CuSO4·5H2O is added after filtering through a filter membrane to prepare seawater containing copper ions.

[0014] Furthermore, the preparation method of the bait in step (2) is as follows: the brine shrimp eggs are mixed with seawater and poured into a brine shrimp incubator, and aerated and cultured for 24 to 48 hours at room temperature and natural light; after the hatching is completed, aeration is stopped, and the brine shrimp nauplii are taken out after standing, and the nauplii are washed and removed, and then placed in seawater to culture the polyps as bait.

[0015] Furthermore, during the period of removing the filamentous algae in step (3), the polyps are fed with the bait prepared in step (2) every day, and the feeding is stopped after the polyps degenerate into dormant roots.

[0016] Furthermore, after the filamentous algae are completely removed in step (4), the original copper ion concentration is maintained for 0 to 15 days and then replaced with normal seawater, thereby ensuring that the filamentous algae are completely removed.

[0017] Furthermore, after the filamentous algae are completely removed in step (4), the revived hydra colony is fed with the bait prepared in step (2) every day, thereby ensuring that the hydra colony further expands and jellyfish are formed and released.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The method of the present invention uses seawater containing copper ions at a concentration of 100 to 250 μg / L to treat filamentous algae infecting polyps, which can not only effectively remove the filamentous algae infecting the polyps, but also the polyps participating in the experiment can quickly recover into healthy hydra groups in normal seawater after being treated with seawater containing copper ions, and continuously form and release healthy jellyfish, which greatly saves the investment of manpower and material resources for long-term maintenance of polyps, improves the efficiency of long-term preservation and maintenance of polyp germplasm, and can also provide support for research on the toxic mechanism of copper ions to cnidarians, the tolerance of cnidarians to heavy metals, and the like.

[0020] 2. The hydra colonies treated by the method of the present invention are clean and free of impurities after the later recovery, meeting the needs of experiments and production. In addition, compared with the hydra cultured in the laboratory for a long time, the hydra treated by the present invention have no obvious difference in growth, jellyfish formation and development, and jellyfish release. The present invention does not have an adverse effect on the growth and development of several hydra and jellyfish. Therefore, this method can be used for algae removal applications of various jellyfish hydra. For different species, the concentration of copper ions used and the treatment time need to be adjusted according to the sensitivity and tolerance of the specific species to copper ions. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1-1 The removal effect of the finger-like branched jellyfish and copper ions on filamentous algae in Example 1 of the present invention;

[0022] Figure 1-2 The effect of copper ions on the polyp and algae area of ​​the finger-like branched jellyfish in Example 1 of the present invention;

[0023] Figure 1-3 This is the situation in which the finger-shaped branch-hand jellyfish produces jellyfish during the recovery period in Example 1 of the present invention;

[0024] Figure 2-1 The effect of different copper ion treatment concentrations and time on the area of ​​filamentous algae in Example 2 of the present invention;

[0025] Figure 2-2 The conditions of the filamentous algae at the 10th and 30th days under different copper ion treatments in Example 2 of the present invention;

[0026] Figure 2-3 The number change of the finger-like branched jellyfish polyp in Example 2 of the present invention during the copper ion treatment period and the recovery period;

[0027] Figure 3 The polyp of the finger-like branched jellyfish in Example 3 of the present invention has been restored to its original state after being treated with copper ions (250 μg / L) twice;

[0028] Figure 4 This is a study on the tolerance of the white-branched jellyfish to copper ions in Example 4 of the present invention;

[0029] Figure 5 This is a study on the tolerance of Xiamen jellyfish to copper ions in Example 5 of the present invention;

[0030] Figure 6 This is a study on the tolerance of the Androsa jellyfish to copper ions in Example 6 of the present invention. DETAILED DESCRIPTION

[0031] The present invention is described in detail below in conjunction with the embodiments and drawings, and the following embodiments should not be construed as limiting the scope of the present invention.

[0032] In the following examples, finger-shaped jellyfish, white-flying jellyfish, Xiamen jellyfish and Androsten jellyfish infected by filamentous algae were used as research objects;

[0033] The daily maintenance method of the polyps of the finger-shaped branched jellyfish, the flying white branched jellyfish, the Xiamen beautiful jellyfish and the Andros jellyfish is as follows: they can be cultured for a long time under the conditions of a salinity of 30-35ppt, a temperature of 20-25℃, natural light, and feeding once a day, and the jellyfish can be released in stages; the culture container is a crystallization dish with a diameter of 12.5cm, with a polyethylene culture dish with a diameter of 10cm built in for the polyps to attach and grow, the culture water is about 300mL, and a culture dish with a diameter of 15cm is added as a lid to prevent the salinity from rising due to water evaporation.

[0034] Example 1

[0035] This embodiment provides a method for removing filamentous algae from the polyp of the finger-like branched jellyfish, comprising the following steps:

[0036] (1) Preparation of seawater and seawater containing copper ions: 30-35 ppt of seawater was prepared using seawater and pure water, and measured using an optical salinity meter. After continuous aeration, the seawater was filtered through a 0.22 μm filter membrane and placed at room temperature for use. CuSO4·5H2O was added to the prepared artificial seawater to prepare seawater containing copper ions. In this embodiment, six concentration gradients of copper ions were set, namely, the copper ion concentrations were 0 (control group), 25, 50, 75, 100, 250, and 500 μg / L, respectively, and were numbered Cu0 (control group), Cu25, Cu50, Cu75, Cu100, Cu250, and Cu500. Each treatment group was repeated three times, and 70 polyps infected with filamentous algae were set in each repeat.

[0037] (2) mixing the brine shrimp eggs with the prepared artificial seawater and pouring them into a brine shrimp incubator, and aerating and culturing them for 24 to 48 hours at room temperature and under natural light; after the hatching is completed, aeration is stopped, and the brine shrimp nauplii are taken out after standing, and the nauplii are washed and removed, and then placed in artificial seawater as bait to cultivate polyps, and diluted as needed for standby use;

[0038] (3) using the copper ion-containing seawater of different concentrations prepared in step (1) to cultivate polyps infected by filamentous algae to remove the filamentous algae, and regularly observing the changes in the polyps and the filamentous algae; during the removal of the filamentous algae, replacing the copper ion-containing artificial seawater every 3 days to maintain the copper ion concentration, and feeding the polyps once a day;

[0039] in, Figure 1-1 a is the polyp of the finger-like branched jellyfish that was not infected by filamentous algae; the green filamentous algae in the control group Cu0 expanded rapidly, covering the entire bottom of the culture dish within 9 days, and quickly squeezed out the living space of the polyp until the polyp died ( Figure 1-1 b); Cu25 group can slow down the growth rate of filamentous algae, and Cu50 group can effectively inhibit the growth of filamentous algae; when the copper ion concentration is less than or equal to 50μg / L, the asexual reproduction of the polyp is inhibited to a certain extent by copper ions, and the overall growth is slow; when the copper ion concentration is 75-250μg / L, the polyp can degenerate to dormant roots ( Figure 1-1 c), the time it takes to enter a dormant state shortens with the increase in copper ion treatment concentration. At this time, filamentous algae can be effectively eliminated, and the filamentous algae in the Cu250 group were completely eliminated within 2 days. When the copper ion treatment concentration was 500μg / L, the polyps died completely within 1 day, and could not be revived even after replacing normal seawater. During the copper treatment period, no jellyfish were produced in all experimental groups.

[0040] (4) After the filamentous algae are completely removed, the original copper ion concentration is maintained for 10 days and then replaced with normal seawater; if the filamentous algae have not been completely removed, normal seawater is replaced 30 days after the copper ion treatment, and the hydra colony enters a recovery period; during the recovery period, the hydra are fed once a day and the water is changed every 3 days;

[0041] Among them, the changes in polyps and filamentous algae are as follows Figure 1-2 As shown; the lines indicate the average value, green represents the algae area (SA: surface area of ​​algae), and purple represents the number of polyps (P: Polyp); Cu0 / 25 / 50 / 75 / 100 / 250 correspond to copper ion concentrations of 0 (control), 25, 50, 75, 100, and 250 μg / L, respectively; the red straight line indicates the time of replacement with normal seawater; it can be seen from the figure that after entering the recovery period, the filamentous algae in the Cu25 and Cu50 groups grew rapidly, covering the entire bottom of the culture dish within 3 to 24 days, and the number of polyps showed a trend of first increasing and then decreasing, and the number of polyps in some groups was close to zero in the later period; the filamentous algae in the Cu75-250 group did not appear again, while the dormant roots of the hydra grew polyps from the 1st to the 16th day, and the hydra population recovered ( Figure 1-1 d), the time required for recovery was prolonged with the increase of the concentration of copper ion treatment in the early stage, and the number of polyps still showed an upward trend at the end of the experiment. The number of polyps in the Cu100 group was the largest, which was 659.0±263.5 at the end of the experiment; during the recovery period, within 37 days from the production of the first jellyfish, the cumulative number of jellyfish released in the Cu75, Cu100, and Cu250 groups was 1597.7±725.1, 849.7±500.0, and 1205.7±1067.0, respectively, and there was no significant difference; after the jellyfish of the three groups matured during the recovery period, they were semi-ellipsoidal, and there was no significant difference in morphology and size from the normal jellyfish of this species.

[0042] In summary, based on a comprehensive analysis of the population size of the polyps of the finger-like branch-hand jellyfish during the copper ion treatment period and the recovery period, the development and release of the jellyfish, and the changes in the algae area, it is recommended that the copper ion concentration for removing the filamentous algae infecting the finger-like branch-hand jellyfish be 75-250 μg / L.

[0043] Example 2

[0044] This example studies the effects of different copper ion treatment concentrations and times on hydra and filamentous algae; the difference from Example 1 is that:

[0045] Steps (1), (3) and (4), in this embodiment, five copper ion concentration gradients are set, namely 0 (control group), 25, 50, 75, 100, and 250 μg / L, which are represented by the numbers Cu0 (control group), Cu25, Cu50, Cu75, Cu100, and Cu250, respectively; the prepared copper ion-containing seawater with different copper ion concentrations is used to culture the polyps infected by filamentous algae to remove the filamentous algae, and the changes of the polyps and the filamentous algae are regularly observed. During the copper ion treatment period, the copper ion-containing seawater is replaced every 2 days to maintain the copper ion concentration, and the polyps are fed with feed once a day; at the same time, the control of the time factor of maintaining the original copper ion concentration and replacing normal seawater after the filamentous algae are completely removed is added; the time control for maintaining the original copper ion concentration is four treatments, namely T0, T5, T10, and T15; T0 is the time when the filamentous algae are completely removed or when the corresponding Cu 2+ After 30 days of treatment, the water was immediately replaced with normal seawater; T5 was when the filamentous algae were completely removed or at the corresponding Cu 2+ After 30 days of treatment, the original treatment was maintained for 5 days and then replaced with normal seawater; T10 was when the filamentous algae were completely removed or at the corresponding Cu 2+ After 30 days of treatment, the original treatment was maintained for 10 days and then replaced with normal seawater; T15 was when the filamentous algae were completely removed or at the corresponding Cu 2+ After 30 days of treatment, continue the original treatment for 15 days and then replace it with normal seawater;

[0046] Among them, during the copper ion treatment period, when the copper ion concentration was 50-250 μg / L, except for the T0 group of Cu50, which always had filamentous algae, the filamentous algae in the other groups could be completely eliminated and no longer appeared in the recovery period; while the Cu25 group could only slow down the growth rate of filamentous algae. Figure 2-1 , Figure 2-2 As shown in the figure, the number of polyps increases when the copper ion concentration is less than 50 μg / L. When the copper ion concentration is 75 μg / L, the number of polyps increases slightly. When the copper ion concentration is 100-250 μg / L, the number of polyps decreases. Figure 2-3 shown.

[0047] The polyps of finger-like branched jellyfish and filamentous algae entered the recovery period. According to the above-mentioned different original copper ion treatment times, normal seawater was replaced, feed was fed once a day, and water was changed every 2 days to keep the water clean; when the copper ion concentration was less than 50μg / L in the early stage, the number of polyps showed a downward trend in the recovery period, and the Cu0 and Cu25 treatment groups were close to 0 at the end of the recovery period; when the copper ion concentration was 75μg / L in the early stage, the number of polyps first increased and then decreased, and the polyp population declined as a whole at the end of the recovery period; when the copper treatment concentration was 100-250μg / L in the early stage, the number of polyps showed an upward trend in the recovery period, among which the number of polyps in the T5 treatment group of Cu100 was the largest at the end of the recovery period, with an average of 149.7±41.3. During the recovery period, maintaining the original copper ion concentration for a treatment time had no significant effect on the removal of filamentous algae, the recovery of polyps, and the jellyfish production. The initial treatment concentration and time had no interactive effect on the cumulative number of jellyfish released during the recovery period.

[0048] In summary, based on a comprehensive analysis of the population of polyps, the development and release of jellyfish, and the changes in algae area during the treatment and recovery periods of different copper ion concentrations, it is recommended that the copper ion concentration for removing filamentous algae be 100-250 μg / L, and normal seawater be replaced after the filamentous algae are completely removed. After the filamentous algae are completely removed, the original copper ion concentration can be maintained for 0-15 days.

[0049] Example 3

[0050] In this embodiment, seawater containing 250 μg / L copper ions was used to treat the filamentous algae infecting the polyps of the finger-like jellyfish for many times;

[0051] The difference between Example 3 and Example 1 is that:

[0052] In step (3), when using seawater containing copper ions to treat the filamentous algae infecting the polyps of the finger-like branched jellyfish, seawater containing 250 μg / L copper ions was used twice; after the first use and successful removal of the filamentous algae, the thriving polyp population was again infected by the filamentous algae due to water pollution on the 66th day, so the filamentous algae were successfully removed by seawater containing 250 μg / L copper ions again, and the polyps recovered within one week of the recovery period and entered a rapid growth period.

[0053] The filamentous algae were removed within one week, and then they were immersed in seawater containing 250 μg / L copper ions for another week before being replaced with normal seawater. The polyps that recovered after the 250 μg / L copper ion treatment had no significant differences in morphology, size, population, formation and development of jellyfish, and size of jellyfish compared with the polyps that were not treated with copper ions. Figure 3As shown, there are 20 independent samples of polyps that have undergone two copper ion treatments (250 μg / L) in this example, and the recovery rate in the recovery period is as high as 95%, of which 1 sample did not recover in the later period because the polyp was in a poor state in the early stage.

[0054] Example 4

[0055] The difference between Example 4 and Example 1 is that: in this embodiment, the flying white branch jellyfish is used as the research object, and the flying white branch jellyfish is treated with seawater containing 100 μg / L copper ions, and the remaining steps are the same as in Example 1;

[0056] like Figure 4 As shown, Figure 4 a is a healthy polyp of the jellyfish; Figure 4 b: Under the treatment of 100 μg / L copper ions, the hydroid roots of the white-branched jellyfish degenerated into a dormant root state; Figure 4 c: After replacing the normal seawater, the dormant roots of the hydra began to recover; Figure 4 d is the dormant root of the hydra regrows the polyp during the recovery period; as can be seen from the figure, under the treatment of 100μg / L copper ions, the filamentous algae are completely removed, the polyp degenerates to the dormant root, and is kept in the seawater with the original copper ion concentration for 5 days before being replaced with normal seawater. After entering the recovery period, the dormant polyp of the flying white branch hand jellyfish regrows the polyp on the second day, and there is no morphological difference with the normal polyp.

[0057] Example 5

[0058] The difference between Example 5 and Example 4 is that: in this example, Xiamen jellyfish is used as the research object, and the remaining processing steps are the same as those in Example 4;

[0059] like Figure 5 As shown, Figure 5 a is a healthy polyp of Xiamen jellyfish; Figure 5 b: Under the treatment of 100 μg / L copper ions, the hydroid roots of Xiamen jellyfish degenerated to the dormant root state; Figure 5 c: After replacing the normal seawater, the dormant roots of the hydra began to recover; Figure 5 d shows the dormant roots of hydra regrow the polyp during the recovery period; as can be seen from the figure, after being treated with 100 μg / L of copper ions, the polyp of Xiamen jellyfish degenerates into polyp roots, and the filamentous algae are completely removed. After being kept in seawater with the original copper ion concentration for 5 days and then replaced with normal seawater, the dormant hydra revived on the second day of the recovery period.

[0060] Example 6

[0061] The difference between Example 6 and Example 4 is that: in this example, the Androsa jellyfish is used as the research object, and the remaining processing steps are the same as those in Example 4;

[0062] like Figure 6 As shown, Figure 6 a is a healthy polyp of Androsa jellyfish; Figure 6 b, 6c: Under the treatment of 100 μg / L copper ions, the tentacles of the polyp of the Androsa jellyfish retracted; Figure 6 d shows the tentacles of the Androsa jellyfish polyp re-extending after changing to normal seawater; as can be seen from the figure, the tentacles of the Androsa jellyfish polyp contracted and the filamentous algae were completely removed when treated with 100 μg / L copper ions. After being kept in the seawater with the original copper ion concentration for 5 days and then replaced with normal seawater, the tentacles of the Androsa jellyfish polyp re-extended within 5 hours of the recovery period.

[0063] In addition to the finger-shaped branched jellyfish, flying white branched jellyfish, and Xiamen beautiful jellyfish listed in the above embodiments, the present invention can also be used for other polyps that can tolerate the stress of a certain concentration of copper ions. Therefore, the method provided by the present invention can be used for algae removal applications for removing polyps infected with various jellyfish.

[0064] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for removing filamentous algae infecting polyps, characterized in that: The following steps are involved: (1) using seawater as a solvent to prepare seawater containing copper ions, wherein the copper ion concentration is 100 to 250 μg / L; (2) preparing food for feeding polyps; (3) using the copper ion-containing seawater with a concentration of 100 to 250 μg / L prepared in step (1) to cultivate polyps infected by filamentous algae to remove the filamentous algae, and replacing the copper ion-containing seawater every 2 to 3 days to maintain the copper ion concentration; (4) After the filamentous algae are completely removed and replaced with normal seawater, the hydra colony enters a recovery period; during the recovery period, the filamentous algae do not reappear, and the dormant hydra grows new hydras after 1 to 16 days.

2. A method for removing filamentous algae infecting polyps according to claim 1, characterized in that: In step (1), seawater with a salinity of 30 to 35 ppt is prepared by using seawater element and pure water, and CuSO4·5H2O is added after filtering through a filter membrane to prepare seawater containing copper ions, wherein the copper ion concentration is 100 to 250 μg / L.

3. The method for removing filamentous algae infecting polyps according to claim 1, characterized in that: The preparation method of the bait in step (2) is as follows: the brine shrimp eggs are mixed with seawater and poured into a brine shrimp incubator, and aerated and cultured for 24 to 48 hours at room temperature and natural light; after the hatching is completed, aeration is stopped, and the brine shrimp nauplii are taken out after standing, and the nauplii are washed and removed, and then placed in seawater to culture the polyps as bait.

4. The method for removing filamentous algae infecting polyps according to claim 1, characterized in that: During the period of removing the filamentous algae in step (3), the polyps are fed with the bait prepared in step (2) every day, and the feeding is stopped after the polyps degenerate into dormant roots.

5. The method for removing filamentous algae infecting polyps according to claim 1, characterized in that: After the filamentous algae are completely removed in step (4), the original copper ion concentration is maintained for 0 to 15 days and then replaced with normal seawater to ensure that the filamentous algae are completely removed.

6. A method for removing filamentous algae infecting polyps according to claim 5, characterized in that: After the filamentous algae are completely removed in step (4), the revived hydra colony is fed with the bait prepared in step (2) every day, thereby ensuring that the hydra colony further expands and jellyfish are formed and released.

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