A method for promoting larval release of Pocillopora damicornis in winter

Abstract

The present invention discloses a method for promoting the larval release of Pocillopora damicornis in winter. a. After the previous larval release of Pocillopora damicornis ends, select healthy Pocillopora damicornis mother colonies and place them in the seawater of a coral culture pond to temporarily adapt to the environment of the culture pond; b. Transfer the coral mother colonies to the seawater, raise the water temperature to 29.0 - 31.0 °C, start recording the water temperature and calculating the effective accumulated temperature when the coral mother colonies are transferred to the seawater. When the effective accumulated temperature is greater than or equal to 240 day·°C, the coral begins to release larvae; when the effective accumulated temperature exceeds 260 day·°C, the coral will have a full-scale larval release. The present invention can break through the limitation of low temperature on the sexual reproduction of corals and meet the demand for corals in the artificial restoration of coral reef ecosystems.

Description

Technical Field:

[0001] The present invention belongs to the field of coral restoration, and particularly relates to a method for promoting the larval release of Pocillopora damicornis in winter. Background Art:

[0002] Due to the rapid degradation of coral reef ecosystems globally, more than half of the coral reefs are currently under severe stress. The most prominent manifestation of coral reef degradation is the reduction in the number of reef-building corals, resulting in a lack of basic functional organisms in the entire ecosystem and an imbalance in the structure and function of the ecosystem. Cultivating reef-building corals through artificial breeding to increase the number of reef-building corals in coral reefs is the most direct way to restore coral reef ecosystems. Currently, there are mainly two methods for artificially breeding reef-building corals: sexual reproduction and asexual fragmentation culture. Compared with asexual fragmentation culture, sexual reproduction can obtain a large number of new coral individuals through artificial incubation of collected planulae (fertilized eggs), meeting the needs of transplantation and restoration while retaining the characteristics of genetic diversity.

[0003] Numerous studies have shown that Pocillopora damicornis has a certain tolerance to seawater warming and acidification. Therefore, it is a common and widespread species in coral reef areas in China and also a dominant species in many reef areas. The reproductive mode of Pocillopora damicornis is larval release type, and it releases planulae every month. Combined with its good environmental adaptability, it is often regarded as a pioneer species for coral reef ecological restoration.

[0004] Currently, the method for obtaining planulae of Pocillopora damicornis is mainly semi-artificial culture with low efficiency. Especially in winter when the temperature is lower (below 25.0°C), problems often occur in the normal collection of larvae. How to improve the collection efficiency of Pocillopora damicornis larvae (especially in winter) has become one of the key technical problems urgently to be solved in coral reef restoration. Summary of the Invention:

[0005] The purpose of the present invention is to provide a method for promoting the larval release of Pocillopora damicornis in winter, which can improve the collection efficiency of Pocillopora damicornis larvae (especially in winter).

[0006] The method for promoting the larval release of Pocillopora damicornis in winter according to the present invention includes the following steps:

[0007] a. After the previous larval release of Pocillopora damicornis ends, select healthy Pocillopora damicornis mother colonies and place them in the seawater of a coral breeding pond to temporarily raise and adapt to the environment of the breeding pond;

[0008] b. Transfer the coral parent to seawater, raise the water temperature to 29.0 - 31.0 °C, start recording the water temperature and calculating the effective accumulated temperature when the coral parent is transferred to the seawater. When the effective accumulated temperature is greater than or equal to 240 day·°C, the coral starts to release larvae; when the effective accumulated temperature exceeds 260 day·°C, the coral will have a full release of larvae.

[0009] Formula for effective accumulated temperature:

[0010] C = N(T - K)

[0011] In the formula, C is the effective accumulated temperature; N is the development duration; T is the temperature during the development duration; K is the growth zero temperature.

[0012] Preferably, the healthy parent is a healthy, relatively large individual (about 15 cm in diameter), disease - free and without partial tissue death.

[0013] Preferably, transferring the coral parent to seawater means transferring the coral parent to the seawater in the larva collection system. If larva release is found, the larvae can be recovered in time the next day.

[0014] Preferably, raising the water temperature to 29.0 - 31.0 °C is carried out in a gradient heating manner, with a heating rate of 0.5 °C / day, to raise the water temperature to 29.0 - 31.0 °C.

[0015] Preferably, after the water temperature is raised to 29.0 - 31.0 °C, keep the water temperature and the water temperature fluctuation does not exceed 0.5 °C.

[0016] The advantages of the present invention are that the collection of planula larvae of Pocillopora damicornis is carried out under semi - artificial cultivation conditions. In winter when the water temperature is relatively low (below 25.0 °C), the normal larva release of Pocillopora damicornis can be promoted by controlling the water temperature, and the time for the start and full release of larvae of Pocillopora damicornis can be calculated using the principle of effective accumulated temperature. The operation is simple, fast, easy to start, and the required equipment is common and easy to obtain. The present invention can break through the limitation of low temperature on the sexual reproduction of corals and meet the demand for corals in the artificial restoration of coral reef ecosystems. Specific embodiments:

[0017] The following embodiments are further descriptions of the present invention, rather than limitations on the present invention.

[0018] Example 1:

[0019] 1. In 2020, a Pocillopora damicornis larva collection experiment was carried out at the Hainan Tropical Marine Biological Experiment Station (Sanya) of the South China Sea Institute of Oceanology, Chinese Academy of Sciences. After the previous larva release of Pocillopora damicornis ended (the eighth day of the lunar calendar in 2020), select healthy, relatively large, disease - free and without partial tissue death parents and put them into the coral breeding pool, and keep them in seawater for 3 - 5 days to adapt to the breeding pool environment.

[0020] 2. Transfer the coral parent to the seawater in the larva collection system. Using the method of gradient heating, raise the water temperature to 29.0 - 31.0 °C at a heating rate of 0.5 °C / day. Observe the state of the coral parent every day, maintain the water temperature, and ensure that the water temperature fluctuation does not exceed 0.5 °C.

[0021] 3. Start recording the water temperature and calculating the effective accumulated temperature when the coral parent is placed in the larva collection system.

[0022] Effective accumulated temperature formula:

[0023] C = N(T - K)

[0024] In the formula, C is the effective accumulated temperature; N is the development duration; T is the temperature during the development duration; K is the growth zero temperature.

[0025] Among them, 5 temperature gradients are set in the experiment: 29.5 °C, 30.9 °C, constant flowing water (average water temperature is 25.2 °C), 28.1 °C, 31.8 °C.

[0026] The results are shown in the following table:

[0027]

[0028]

[0029] As can be seen from the above table, when the effective accumulated temperature exceeds 240 day·°C, the coral starts to release larvae. It is necessary to observe whether the coral releases larvae every night; when the effective accumulated temperature exceeds 260 day·°C, the coral may have a full release of larvae. If it is found that the larvae are released, the larvae should be recovered in time the next day.

[0030] The above is only a preferred example of the present invention and is not used to limit the present invention. The protection scope of the present invention is not limited to this. Any obvious modification, equivalent replacement, improvement, etc. within the technical principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for promoting the larval release of Pocillopora damicornis in winter, characterized in that, It includes the following steps: a. After the previous larval release of Acropora cervicornis, select healthy Acropora cervicornis parent colonies and place them in the seawater of the coral culture pond to temporarily adapt to the environment of the culture pond. b. Transfer the coral parent colonies to seawater, raise the water temperature to 29.0 - 31.0 °C. Start recording the water temperature and calculating the effective accumulated temperature when the coral parent colonies are transferred to seawater. When the effective accumulated temperature is greater than or equal to 240 day∙°C, the coral begins to release larvae; when the effective accumulated temperature exceeds 260 day∙°C, the coral will have a full larval release. Effective accumulated temperature formula: C = N(T - K) In the formula, C is the effective accumulated temperature in day∙°C; N is the development duration in day; T is the temperature in °C during the development duration; K is the growth zero temperature in °C.

2. The method according to claim 1, characterized in that, The transfer of the coral parent colonies to seawater means transferring the coral parent colonies to the seawater of the larval collection system.

3. The method according to claim 1, wherein The raising of the water temperature to 29.0 - 31.0 °C is carried out in a gradient heating manner, with a heating rate of 0.5 °C / day to raise the water temperature to 29.0 - 31.0 °C.

4. The method according to claim 1, characterized in that After the water temperature is raised to 29.0 - 31.0 °C, keep the water temperature and the water temperature fluctuation does not exceed 0.5 °C / day.

Images