Method for removing hooked shrimps on kelp seedling ropes

Abstract

The invention discloses a method for removing hooked shrimps on kelp seedling ropes, and belongs to the technical field of large seaweed cultivation. The kelp seedling ropes polluted by the hooked shrimps are soaked in an ammonia water preparation which is blended with fresh water and has the ammonia content of 0.2-0.3% for 5-10 seconds after being subjected to water control for 5-8 seconds, so that not only can the adult hooked shrimps be removed, but also the adult hooked shrimps can be removed; and larvae of the penaeus undatus in the nest can be removed, and the removal effect on the fouling organisms is optimal. In addition, the method does not affect normal growth of kelp seedlings, is short in operation time, high in operation efficiency and simple in operation method, and has practical application value for kelp cultivation work.

Description

Technical Field

[0001] The present invention belongs to the technical field of large seaweed cultivation, and particularly relates to a method for removing gammarids on the seedling ropes of kelp. Background Art

[0002] Kelp (Laminaria japonica) has high comprehensive value and is widely used in the fields of food, medicine, chemical industry, etc. In the food field, kelp is a nutritious edible brown alga containing more than 60 kinds of nutrients. In the medical field, kelp has high health care value, and alginate extracted from kelp has the effects of reducing serum cholesterol, triglycerides in blood and blood sugar. In the industrial field, kelp is the main raw material for extracting iodine, alginate and mannitol. Among them, iodine is used to make disinfectants such as iodine tincture and iodoform in medicine; alginate is the best sizing agent, food additive, stabilizer and thickener in modern printing and dyeing industry; mannitol has wide applications in medicine, synthetic chemical industry and microbiology.

[0003] Kelp is one of the main economic algae in China's aquaculture industry. China ranks first in the world in terms of kelp production and aquaculture scale. In 2022, China's kelp production reached 143.1×10 4 t. Kelp production includes the processes of indoor seedling cultivation, sea area temporary cultivation of seedlings, seedling separation, cultivation and harvesting. Among them, the indoor seedling cultivation stage is carried out in the seedling cultivation workshop on land. When the kelp seedlings grow to 1-2 cm on the seedling ropes in the indoor seedling cultivation pool, the seedling ropes need to be transferred to the sea for temporary cultivation. When the kelp seedlings on the seedling ropes grow to about (20±2) cm, the kelp seedlings are removed from the seedling ropes and clamped onto the seedling ropes for cultivation.

[0004] During the transfer of the seedling ropes to the sea for temporary cultivation, a large number of gammarids will parasitize on the roots of the seedling ropes and kelp seedlings. Gammarids use attached mud as the substrate and build nursery field nests with holes on the kelp seedling ropes. Sometimes they will cover the small kelp seedlings, and a large number of gammarids will also attach to the large seedlings, making the large seedlings bend and not strong, which harms the kelp seedlings. In recent years, due to the influence of factors such as global warming and environmental changes, the seawater temperature has risen, and the harm of gammarids to the temporarily cultivated kelp seedlings has become more serious. It is urgent to solve the problem of the harm of gammarids to the temporarily cultivated kelp seedlings in kelp aquaculture production. Summary of the Invention

[0005] In view of the above-mentioned prior art, the present invention proposes a method for removing the pollution of gammarids on the seedling ropes of kelp in the sea area without affecting the normal growth of kelp seedlings.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for dealing with gammarids on the kelp seedling ropes, including the following steps:

[0008] Take the kelp seedling ropes contaminated by amphipods, control the water for 5 - 8 seconds, then put them into an ammonia water preparation made with fresh water and having an ammonia content of 0.2 - 0.3% and soak for 5 - 10 seconds. Then take out the kelp seedling ropes from the ammonia water preparation, transfer them to seawater, rinse and dilute the ammonia preparation in the seawater, and then continue the hanging cultivation.

[0009] The ammonia water preparation with an ammonia content of 0.2 - 0.3% means that the mass percentage of NH3 in the ammonia water preparation is 0.2 - 0.3%.

[0010] The salinity of the fresh water is 0.5‰.

[0011] The exposure time from when the kelp seedling ropes leave the ammonia water preparation made with fresh water to when they are immersed in seawater is ≤5s.

[0012] The kelp seedling ropes are vinylon ropes with attached kelp seedlings, each hanging rope being 9m long and 3mm in diameter. The ratio of the seedling ropes to the ammonia water preparation made with fresh water is 100 - 120 hangs / 100L.

[0013] The beneficial effects of the present invention:

[0014] 1. Comprehensively utilize fresh water and ammonia water to treat amphipods, achieving a combined effect that cannot be achieved by using only fresh water or only ammonia water preparation made with seawater alone. Ammonia water has a certain killing effect on amphipods, which are common fouling animals in seawater aquaculture. However, when using only low - concentration ammonia water (usually prepared with seawater) to treat kelp seedling ropes fouled by amphipods, without harming the kelp seedlings, the killing effect on amphipods is not ideal, and the treatment time required is too long (more than 30 seconds), which is not operable in production. Fresh water also has a certain killing effect on amphipods, but when using only fresh water to treat kelp seedling ropes fouled by amphipods, within the time of not harming the kelp seedlings, the killing effect on amphipods is not ideal; within the treatment time that can effectively kill amphipods, the kelp seedlings are damaged and turn green and fester. Based on repeated experiments, the present invention uses fresh water to prepare an ammonia water preparation with a specific concentration to treat kelp seedling ropes fouled by amphipods. The synergistic effect of ammonia water and fresh water can improve the killing effect on amphipod larvae in the nests, and at the same time, there is no harm to the kelp seedlings.

[0015] 2. The method provided by the present invention is operable in production. The present invention uses ammonia water plus fresh water (ammonia content 0.2 - 0.3%) to soak the kelp seedling ropes. Soaking for 5 seconds and 10 seconds both have an effect on removing amphipods, and it is harmless to the kelp seedlings. The kelp seedling ropes temporarily cultured in the sea area (generally 9 meters long) are taken down from the floating raft and transferred to the ammonia water preparation formulated with fresh water. The operation process takes between 5 - 10 seconds, which is just used for water control and avoids serious dilution of the ammonia water preparation; soaking in the ammonia water preparation for 5 - 10 seconds, the time is not long and can be accepted in production operation; taking it out from the ammonia water preparation and putting it into seawater can be completed within 5 seconds. The rectification process is easy to operate and feasible in production, avoiding errors caused by hasty time and actual operation time and bringing adverse effects.

[0016] 3. The method provided by the present invention has a promoting effect on the growth of kelp seedlings. Ammonia water is harmful to the fouling organism amphipods, while low - concentration ammonia can be utilized by kelp seedlings as a nutrient element, which is beneficial to the growth of kelp seedlings. In the method of this invention, the combination of fresh water and ammonia water is used to achieve the effect of removing the fouling organism amphipods on the kelp seedling ropes without affecting the subsequent growth and development of the kelp seedlings. Description of the Drawings

[0017] Figure 1 Kelp seedlings suspended in the sea area for 5 days after being treated with fresh water ammonia water preparation (ammonia concentration 0.25%) for 10 seconds.

[0018] Figure 2 Kelp seedlings suspended in the sea area for 1 day after being treated with fresh water ammonia water preparation (ammonia concentration 1%) for 10 seconds turn green and rot. Detailed Embodiments

[0019] It should be noted that the following detailed description is illustrative and aims to provide further explanation for the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0020] The following combines examples to further describe in detail the specific embodiments of the present invention. The following detailed description is illustrative and aims to provide further explanation for the present application rather than limiting the scope of the present invention.

[0021] As mentioned above, amphipods will cause harm to the temporarily cultured kelp seedlings in kelp aquaculture production. In actual production, the indoor seedlings are transferred to the sea area for temporary culture around October every year, and the seedlings reaching the seeding - clip specification are clipped onto the aquaculture seedling ropes in November and cultured on floating rafts in the sea area. The main harvest period is from May to June of the following year. In October 2024, a large number of amphipods attached to the kelp seedling ropes temporarily cultured in the Bairanzi Sea area of Lushunkou District, Dalian, and built a nursery ground in the nests between the seedling ropes and the roots of the kelp seedlings, having a negative impact on the growth of the kelp seedlings. It is urgent to explore a suitable solution.

[0022] Based on this, the present invention provides a method for removing the harm of hooked shrimps on the kelp seedling ropes to kelp seedlings during the temporary cultivation period. By using fresh water to prepare an ammonia water preparation with a specific concentration to treat the kelp seedling ropes fouled by hooked shrimps, the synergistic effect of ammonia water and fresh water not only improves the killing effect on the juvenile hooked shrimps in the nests, but also causes no harm to the kelp seedlings, promoting the development of kelp cultivation technology.

[0023] The test materials not specifically described used in the embodiments of the present invention are all conventional test materials in the art and can be obtained through commercial channels.

[0024] The salt content of the fresh water used in the embodiments of the present invention is 0.5‰. The seawater is sand-filtered seawater with a salt content of 34.1‰.

[0025] The ammonia water preparations with different ammonia concentrations are obtained by adding fresh water to dilute the high-concentration ammonia water solution.

[0026] Example 1: Immersion of kelp seedling ropes with ammonia water in different preparation methods

[0027] Cut the kelp seedling ropes temporarily cultivated at sea, each section is 20 cm long, and use fresh water to prepare an ammonia water preparation (ammonia concentration 0.25%) and seawater to prepare an ammonia water preparation (ammonia concentration 0.25%) to immerse the cut kelp seedling ropes respectively. The seawater used in the experiment comes from the kelp temporary cultivation area in Bailanzi Sea Area. The specific situation is as follows:

[0028] After draining the water from the cut kelp seedling ropes for 5 seconds respectively, treat them according to the immersion treatment methods shown in Table 1. After the immersion treatment, take out the kelp seedling ropes and transfer them to seawater. The exposure time from when the kelp seedling ropes leave the treatment liquid to when they are put into seawater does not exceed 5 seconds. After rinsing in seawater, continue to hang and cultivate. Starting from the next day after the treatment, count the clearance effect of different treatments on the hooked shrimp nests. Calculate the clearance rate of hooked shrimp nests according to (the initial number of hooked shrimp nests - the number of hooked shrimp nests after 3 days of treatment) / the initial number of hooked shrimp nests × 100%. The statistical results are shown in Table 2.

[0029] Table 1: Immersion treatment methods of each group of kelp seedling ropes

[0030] Serial number Treatment method Concentration Soaking time Treatment group 1 Fresh water diluted ammonia preparation 0.25％ 5s Treatment group 2 Fresh water diluted ammonia preparation 0.25％ 10s Treatment group 3 Seawater diluted ammonia preparation 0.25％ 10s Treatment group 4 Seawater diluted ammonia preparation 0.25％ 20s

[0031] Table 2: Statistical results of the clearance effect of different treatments on the hooked shrimp nests

[0032]

[0033] Furthermore, observe the growth of kelp seedlings on the kelp seedling ropes of all treatment methods and find that no abnormal greening and rotting phenomena are found in the kelp seedlings of all treatment methods, and all are Figure 1The state of normal growth shown. The kelp seedling ropes that have not been operated on and are not damaged by gammarids are used as the control group (treatment group 5). 5 cm of the kelp seedling ropes soaked by the above 4 treatment methods and the kelp seedling ropes of the control group are taken, and the growth of the kelp seedlings is statistically analyzed in detail. The statistical results are shown in Table 3.

[0034] Table 3: Growth of kelp seedlings

[0035]

[0036] It can be seen from Table 3 that the density, maximum value, minimum value and average value of the kelp seedlings soaked by all treatment methods are relatively similar, with little difference. Under the same conditions, the combined treatment time of fresh water and ammonia water is shorter (5 - 10 seconds), which meets the requirements of actual production. Therefore, the treatment method of using a fresh water ammonia preparation (ammonia concentration 0.25%) and soaking for 5 - 10 seconds is the best method to remove fouling organisms on the kelp seedling ropes.

[0037] Comparative Example 1: Soaking kelp seedling ropes with a fresh water ammonia preparation (ammonia concentration 1%)

[0038] After intercepting 20 cm of the kelp seedling ropes in the sea for temporary cultivation and controlling water for 5 seconds, transfer them to a fresh water - prepared ammonia preparation (ammonia concentration 1%) and soak for 10 s. After the soaking treatment, take out the kelp seedling ropes and transfer them to seawater for continued hanging cultivation. The exposure time from when the kelp seedling ropes leave the fresh water - prepared ammonia preparation (ammonia concentration 1%) to when they are put into seawater does not exceed 5 seconds.

[0039] On the next day of the treatment, it was found that the kelp seedlings turned green and rotted ( Figure 2 ), indicating that too high ammonia content in the fresh water - prepared ammonia preparation will affect the normal growth of kelp seedlings.

[0040] The method of the present invention rationally designs a method for removing gammarids that harm kelp seedlings on kelp seedling ropes: soaking in a fresh water ammonia preparation (ammonia concentration 0.25%) for 5 - 10 seconds. This removal method can not only remove adult gammarids, but also remove gammarid larvae in the nests, and has the best effect on removing fouling organisms. In addition, this method does not affect the normal growth of kelp seedlings, and the density and length are similar to the results in actual production. The operation time is short, the operation efficiency is high, and the operation method is simple, which has practical application value for kelp farming work.

[0041] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for dealing with shrimp hooked on the seedling ropes of kelp, characterized in that, It includes the following steps: Take the kelp seedling ropes contaminated by hooked shrimps hanging in the sea area. After controlling the water for 5 - 8 seconds, put them into an ammonia water preparation with an ammonia content of 0.2 - 0.3% prepared with fresh water and soak for 5 - 10 seconds. Then take out the kelp seedling ropes from the ammonia water preparation, transfer them to seawater, rinse and dilute the ammonia preparation in the seawater, and then continue the hanging cultivation.

2. The method according to claim 1, wherein The kelp seedling ropes are vinylon ropes with attached kelp seedlings, each rope being 9 meters long and 3 mm in diameter.

3. The method according to claim 1, wherein The salinity of the fresh water is 0.5‰.

4. The method according to claim 1, characterized in that, The exposure time from when the kelp seedling ropes leave the ammonia water preparation prepared with fresh water to when they are immersed in seawater is ≤5 s.

5. The method according to claim 1, wherein The ratio of the kelp seedling ropes to the ammonia water preparation prepared with fresh water is 100 - 120 ropes / 100 L.

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