Method for inducing coral larva discharge and high-adhesion-rate larva culture method

Abstract

The invention discloses a method for inducing coral larva discharge and a high-adhesion-rate larva culture method. And slowly adding the high-salinity seawater into the seawater containing the coral cervi, and inducing the coral cervi to discharge the plantlet larvae. According to the method, high-salinity seawater is used for inducing the coral antler to discharge the planula larvae, so that the damage of a long-time high-temperature induction method to the coral parent and symbiotic zooxanthellae is remarkably reduced, the risks of whitening and death of the coral are avoided, and the survival rate and the recovery speed of the coral parent are increased.

Description

Technical Field

[0001] The invention belongs to the technical field of coral larvae culture, and particularly relates to a method for inducing coral larvae to spawn and a method for culturing larvae with a high attachment rate. Background Art

[0002] The coral reef ecosystem is known as one of the most complex and precious marine ecosystems on Earth, carrying rich biodiversity, profound scientific and educational value, and huge economic contributions. However, in recent decades, the dual pressures of intensified human activities and climate change have led to serious degradation of the global coral reef ecosystem, causing immeasurable losses to the economy and the environment. In order to protect corals, a rare marine resource, artificial ecological restoration of coral reefs is particularly urgent.

[0003] In the restoration of coral reef ecosystems, the most direct and effective method is to cultivate reef-building corals through artificial breeding and transplant them to the restoration area to increase the number and diversity of corals. It is particularly worth mentioning that the sexual reproduction of reef-building corals has become a key link in the restoration of coral reef ecosystems because it can significantly enhance genetic diversity and improve the stress resistance of corals. Compared with asexual reproduction technology, sexual reproduction can not only effectively expand the distribution range of corals, but also significantly enhance the ability of corals to adapt to the changing marine environment in the future through genetic recombination.

[0004] Pocillopora damicornis is a coral that can reproduce by expelling juveniles. Its ability to directly expel floating juveniles enables it to quickly emerge and begin ecological succession and the reconstruction of biological communities when the ecosystem is damaged or disturbed. Its excellent reproductive ability and high adaptability make it a "pioneer species" for coral reef ecological restoration.

[0005] However, current methods of artificially inducing the larvae of Acropora hornbeams, such as high temperature, chemicals and microbial stimulation, will cause varying degrees of damage to the coral mother. In particular, the high-temperature induction method usually needs to last for 3-5 days, and long-term high-temperature treatment often leads to the detachment of the coral's symbiotic zooxanthellae, which in turn causes coral bleaching or even death. Even the surviving mother body needs a long period of recovery in a suitable environment. Therefore, how to induce the larvae of Acropora hornbeams to spawn quickly and with low damage, so as to prepare for the next induced larvae, has become one of the key technical issues that need to be solved urgently.

[0006] In addition, the attachment of coral larvae is an important process for reproduction and growth, and its success or failure is directly related to the reproduction of the population and the health of the coral reef ecosystem. However, the larvae are extremely sensitive to changes in external environmental factors during the attachment and metamorphosis stage. At present, there are still problems such as low attachment and metamorphosis rate, long time consumption, and high mortality rate in the cultivation process of coral larvae. Therefore, how to increase the attachment and metamorphosis rate of larvae, shorten the attachment and metamorphosis time, and reduce the mortality rate has become an important issue that needs to be solved urgently in the cultivation of coral larvae. Similarly, how to increase the attachment and metamorphosis rate of coral larvae and shorten the attachment and metamorphosis time in the artificial breeding process has also become a bottleneck that urgently needs to be broken through. Summary of the invention

[0007] In view of this, the present invention is committed to developing a rapid and low-damage method for inducing larvae of Acropora hornbeam and cultivating them with a high attachment and metamorphosis rate. By improving the efficiency of larval induction and attachment and metamorphosis, it can not only provide important experimental method support for coral larval cultivation research, but also provide key technologies for coral reef ecological restoration to promote the comprehensive recovery of coral reef ecosystems.

[0008] The rapid and low-damage coral larvae induction method of the present invention comprises the following steps:

[0009] High-salinity seawater was slowly added to the seawater containing Acropora spp. to induce Acropora spp. to expel planula larvae.

[0010] The high-salinity seawater is 65‰ high-salinity seawater.

[0011] Preferably, a peristaltic pump is used to titrate 65‰ high-salinity seawater into a 35‰ seawater culture tank containing Acropora hornensis for 18 hours. After completion, the salinity is 45‰, inducing Acropora hornensis to expel planula larvae, absorb the larvae into a culture dish, and gradually replace them with 35‰ seawater to reduce the salinity to 35‰ for subsequent culture.

[0012] The stepwise replacement of 35‰ seawater means stepwise replacement of 35‰ seawater within 10 minutes.

[0013] The present invention utilizes high-salinity seawater to induce Acropora hornba corals to expel planktonic larvae, significantly reducing the damage to the coral mother and symbiotic zooxanthellae caused by a long-term high-temperature induction method, avoiding the risk of coral bleaching and death, and improving the survival rate and recovery speed of the coral mother.

[0014] The present invention also provides a method for cultivating coral larvae with a high attachment and metamorphosis rate, which uses artificial seawater with a salinity of 35‰ as a larval culture medium to induce the attachment of Acropora cup coral larvae, and cultivates them in a light incubator to allow the larvae to attach.

[0015] The present invention utilizes filtered artificial seawater with a salinity of 35‰ as a larval culture medium and cultures the larvae in a light culture box, so that the larvae attach to the bottom of the culture dish in a short time (20 hours), significantly improving the attachment metamorphosis rate (up to 96%), shortening the culture cycle, reducing the mortality rate of the larvae, and improving the survival rate and reproductive efficiency of the larvae. DETAILED DESCRIPTION

[0016] The following examples are provided to further illustrate the present invention, rather than to limit the present invention.

[0017] Embodiment 1:

[0018] 1. Implementation plan for coral larvae induction:

[0019] a. Add artificial sea salt for coral cultivation to pure water to prepare 2L of high-salinity seawater with a salinity of 65‰ and 3L of normal seawater with a salinity of 35‰;

[0020] b. Select 10cm 2 Healthy-sized Acropora pocillopora were placed in a 6-L culture tank containing 3 L of artificial seawater with a salinity of 35‰;

[0021] c. Use an air pump to oxygenate the water in the aquarium and provide water flow; maintain the water temperature at 25°C; use a fill light to provide light, the light intensity is about 12000lx, and the light / dark cycle is 12:12h;

[0022] d. Use a peristaltic pump to titrate 65‰ high-salinity seawater into the aquaculture tank at a rate of 83.3mL / h for 18 hours. After completion, the salinity is about 45‰;

[0023] e. 12 hours after the start of induction, continuous observation of the discharge of planula larvae began;

[0024] f. Use a rubber-tipped glass dropper to draw the larvae into a 90 mm plastic culture dish and gradually replace the 35‰ seawater within 10 minutes to reduce the salinity to 35‰ for subsequent culture. After 20 hours, the survival rate of planula larvae was 100%.

[0025] g. At this time, the mother polyp shrinks, and no bleaching or escape occurs. The mother is placed in a marine aquarium with a salinity of 35‰ for recovery. After 1 day, the polyp begins to stretch out, and after 3-5 days, the polyp is fully stretched and restored to health.

[0026] 2. Implementation plan for cultivating coral larvae with high attachment and metamorphosis rate:

[0027] a. Prepare artificial seawater with a salinity of 35‰ and filter it using a 0.22μm microporous filter membrane as a culture medium for coral larvae;

[0028] b. Pipette the induced larvae into a 90 mm plastic culture dish and add filtered artificial seawater;

[0029] c. Place the culture dish in a light incubator with a light intensity of about 6000 lx and a light / dark cycle of 12:12h;

[0030] d. After 20 hours of culture, the planula larvae gradually attached to the bottom of the culture dish, and the attachment metamorphosis rate was 73% at this time;

[0031] e. The unattached larvae were transferred to a new culture dish and placed in the incubator to continue attaching. After 18 hours, the attachment and metamorphosis rate was 100%.

[0032] f. The culture dish with attached larvae is placed in a 6L culture tank, and an air pump is used to oxygenate the water in the culture tank and provide water flow; the water temperature is maintained at 25°C; a fill light is used to provide light, and the light / dark cycle is 12:12h;

[0033] g. Observe the growth of the larvae every day. After 7 days, the larvae gradually metamorphose into complete polyps, with a survival rate of 100%. After 12 days, new polyps can be seen sprouting and gradually growing, with a survival rate of 97%.

Claims

1. A method for inducing coral larvae to spawn, characterized in that: The following steps are involved: High-salinity seawater was slowly added to the seawater containing Acropora spp. to induce Acropora spp. to expel planula larvae.

2. The method for inducing coral larvae to spawn according to claim 1, characterized in that: The high-salinity seawater is 65‰ high-salinity seawater.

3. The method for inducing coral larvae to spawn according to claim 1 or 2, characterized in that: A peristaltic pump is used to titrate 65‰ high-salinity seawater into a 35‰ seawater aquaculture tank containing Acropora hornense corals for 18 hours. After completion, the salinity is 45‰, which induces Acropora hornense corals to expel floating larvae, absorb the larvae into the culture dish, and gradually replace them with 35‰ seawater to reduce the salinity to 35‰ for subsequent culture.

4. The method for inducing coral larvae to spawn according to claim 3, characterized in that: The stepwise replacement of 35‰ seawater means stepwise replacement of 35‰ seawater within 10 minutes.

5. A method for cultivating coral larvae with a high attachment and metamorphosis rate, characterized in that: The method uses artificial seawater with a salinity of 35‰ as a larval culture medium to induce the attachment of Acropora hornba larvae, and cultivates them in a light incubator to allow the larvae to attach.