A method for co-culturing Undaria pinnatifida and Laminaria angustata on aquaculture ropes

Abstract

The present invention discloses a method for co-culturing Undaria pinnatifida and juvenile Laminaria japonica on a culture rope for seedlings, belonging to the technical field of large seaweed cultivation. In the present invention, Laminaria japonica seedlings are first collected onto the culture rope for Undaria pinnatifida seedlings, and then Undaria pinnatifida seedlings are clipped onto the culture rope. On the same culture rope and in the same water body, Undaria pinnatifida and Laminaria japonica grow simultaneously. Undaria pinnatifida is harvested in the early stage, and juvenile Laminaria japonica is harvested in the later stage. It is realized that both Undaria pinnatifida and juvenile Laminaria japonica are harvested on the same water body and the same seedling rope. This not only changes the practice in the prior art of collecting Laminaria japonica seedlings and Undaria pinnatifida seedlings onto different culture ropes, but also improves the prior art methods of polyculture and intercropping of Laminaria japonica and Undaria pinnatifida in the same water area. This research improves the cultivation efficiency and benefits of Laminaria japonica and Undaria pinnatifida per unit water body, increases the utilization rate of sea areas, makes contributions to the cultivation of Undaria pinnatifida and Laminaria japonica, and has practical application value for marine fishery production.

Description

Technical Field

[0001] The present invention relates to the technical field of large seaweed cultivation, and particularly relates to a method for co-cultivating Undaria pinnatifida and Laminaria japonica on a cultivation seedling rope. Background Art

[0002] Undaria pinnatifida is not only an edible economic brown alga but also can be used as a raw material to extract alginic acid. Undaria pinnatifida is a natural treasure house of trace elements and minerals, containing more than a dozen essential amino acids, calcium, iodine, zinc, selenium, folic acid and various vitamins for the human body.

[0003] Laminaria japonica is a brown alga rich in nutrients, containing more than 60 kinds of nutrients, which can be directly eaten or used as industrial raw materials. Laminaria japonica is rich in laminaran polysaccharides, including alginate, fucoidan and laminarin, and also contains various active ingredients such as acidic polysaccharide substances, fucogalactan sulfate, zosterin, galacturonic acid, laminine, taurine, bifidogenic factor, etc.

[0004] Most of the existing cultivation methods for Undaria pinnatifida and Laminaria japonica are single cultivation. In order to make full use of sea area resources and improve efficiency, researchers have tried to inter-culture and co-culture Laminaria japonica and Undaria pinnatifida. The paper "Experiment on Cultivating Undaria pinnatifida between Rafts of Laminaria japonica" (Li Hongji, Acta Hydrobiologica Sinica) introduced the method of inter-cultivating Laminaria japonica and Undaria pinnatifida on different cultivation ropes; the paper "Research on the Co-cultivation Technology of Laminaria japonica and Undaria pinnatifida" (Jiang Xiaohui, Proceedings of the Fisheries Academic Forum of 16 Provinces (Municipalities and Autonomous Regions) in the South) introduced the co-cultivation technology of Laminaria japonica and Undaria pinnatifida. These technologies are to separately clamp Laminaria japonica or Undaria pinnatifida onto different cultivation seedling ropes, temporarily vertically cultivate one variety, and then horizontally hang it at a specific time; or first densely cultivate one variety and then separate it at an appropriate time. A large amount of manpower is consumed in daily production operations such as routine inspections, and Laminaria japonica and Undaria pinnatifida are in a competitive relationship during the cultivation process, resulting in unsatisfactory efficiency and limited application. Therefore, since the co-cultivation and inter-cultivation technology of Laminaria japonica and Undaria pinnatifida was created, it has not been widely applied. Currently, in aquaculture production, the cultivation of Undaria pinnatifida and Laminaria japonica still mostly adopts the single cultivation method. The market demand for Undaria pinnatifida and Laminaria japonica is increasing, but the area of suitable sea areas for cultivation is limited. Therefore, in order to improve the utilization rate of sea areas, there is an urgent need for methods to improve the aquaculture efficiency and benefit per unit water body in marine fishery production. Summary of the Invention

[0005] In view of the above-mentioned prior art, the present invention provides a method for co-culturing Undaria pinnatifida and juvenile Laminaria japonica on a cultivation rope. In the method of the present invention, the cultivation rope for Undaria pinnatifida is first used for Laminaria japonica spore seeding. After the cultivation rope has collected the zoospores of Laminaria japonica, Undaria pinnatifida seedlings are then clipped onto it. The Undaria pinnatifida seedlings and Laminaria japonica seedlings are on the same cultivation rope, and Laminaria japonica and Undaria pinnatifida grow simultaneously in the same water body. Undaria pinnatifida is harvested in the early stage, and juvenile Laminaria japonica is harvested in the later stage, achieving the harvest of both Laminaria japonica and Undaria pinnatifida on the same water body and the same seedling rope. This research improves the efficiency and benefits of seaweed cultivation per unit water body, increases the utilization rate of sea areas, contributes to the cultivation work of Laminaria japonica and Undaria pinnatifida, and has practical application value for marine fishery production.

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

[0007] In the first aspect of the present invention, there is provided a method for co-culturing Undaria pinnatifida and juvenile Laminaria japonica on a cultivation rope, including the following steps:

[0008] (1) In October, the air-dried Laminaria japonica reproductive thalli are placed in a container filled with seawater; when the number of zoospores released by the Laminaria japonica in the seawater reaches 2000 - 3000 per milliliter, the reproductive thalli are taken out, and the cultivation rope is placed in the container containing the Laminaria japonica zoospores for spore seeding; after spore seeding, the cultivation rope is taken out and temporarily cultured in seawater.

[0009] (2) When the Undaria pinnatifida seedlings on the seedling rope reach the clipping specification, the seedling rope temporarily cultured in the sea area is taken out and cut into seedling segments of 2 - 5 cm; the temporarily cultured cultivation rope is taken out, and the Undaria pinnatifida seedling segments are clipped onto the cultivation rope at intervals of 30 - 50 cm.

[0010] (3) Immediately after clipping the Undaria pinnatifida seedlings, the cultivation rope is transferred to a floating raft for cultivation in the sea area.

[0011] (4) In February - April of the following year, when the width of the Undaria pinnatifida stem reaches 2.5 cm, the Undaria pinnatifida is harvested; the Laminaria japonica seedlings are continuously cultured until juvenile Laminaria japonica is harvested.

[0012] Further, in step (1), the Laminaria japonica reproductive thalli are air-dried in the air at 15 - 20 °C for 1 - 3 hours.

[0013] Further, in step (1), the air-dried Laminaria japonica reproductive thalli are placed in a container filled with seawater at 7 - 11 °C, and the water temperature is maintained at 7 - 11 °C during storage.

[0014] Further, in step (1), the cultivation rope is soaked in seawater at 7 - 11 °C before spore seeding.

[0015] Further, in step (1), 5 - 15 hours after spore seeding, the cultivation rope is taken out and temporarily cultured in flowing seawater at 7 - 11 °C.

[0016] Furthermore, the temporary cultivation lasts for 2 - 4 days, during which the illumination is ≤ 2000 lx.

[0017] Furthermore, in step (3), the distance between floating rafts is 6 - 10 m, the distance between seedling ropes is 120 - 160 cm, and 50 - 70 cultivation seedling ropes are set per mu of sea area.

[0018] Advantages of the present invention:

[0019] In the present invention, the cultivation seedling ropes of Undaria pinnatifida are first used for sporeling collection of Laminaria japonica. After the cultivation seedling ropes collect the zoospores of Laminaria japonica, Undaria pinnatifida seedlings are then clipped. The Undaria pinnatifida seedlings and Laminaria japonica seedlings are on the same cultivation seedling rope, and Laminaria japonica and Undaria pinnatifida grow simultaneously in the same water body. Undaria pinnatifida is harvested in the early stage, and Laminaria japonica young plants are harvested in the later stage. It realizes the harvest of both Laminaria japonica and Undaria pinnatifida on the same water body and the same seedling rope, changing the traditional method of growing Laminaria japonica seedlings and Undaria pinnatifida seedlings on different seedling ropes. And compared with the prior art methods of co - cultivating and inter - cultivating Laminaria japonica and Undaria pinnatifida in the same water area, the method of the present invention reasonably arranges the growth cycles of Undaria pinnatifida seedlings and Laminaria japonica seedlings. In the same water body, Laminaria japonica and Undaria pinnatifida are co - cultivated starting from October, but the development and growth of Laminaria japonica seedlings lag behind that of Undaria pinnatifida, which does not affect the growth of Undaria pinnatifida. After harvesting Undaria pinnatifida from February to April, Laminaria japonica continues to grow on the seedling rope. When Laminaria japonica grows to an appropriate stage for harvesting, small Laminaria japonica is harvested. Before harvesting Undaria pinnatifida, the cultivation management is completely the same as that of single - cultivating Undaria pinnatifida, reducing the complexity of daily management operations, reducing the workload, and saving labor costs. This research improves the efficiency and benefits of seaweed cultivation per unit water body, increases the utilization rate of sea areas, makes contributions to the cultivation of Laminaria japonica and Undaria pinnatifida, and has practical application value for marine fishery production. Description of the drawings

[0020] Figure 1 Drying the Laminaria japonica reproductive thalli in the shade.

[0021] Figure 2 The reproductive thalli are just put into the cold water in the large white bucket, and the reproductive thalli have not released zoospores yet.

[0022] Figure 3 The reproductive thalli release zoospores, and the seawater becomes turbid.

[0023] Figure 4 Putting the cultivation seedling rope into the zoospore solution for sporeling collection.

[0024] Figure 5 The cultivation seedling rope with Undaria pinnatifida seedlings clipped on it.

[0025] Figure 6 Checking the cultivation seedling rope for co - cultivating Laminaria japonica and Undaria pinnatifida on February 15, 2023. The Laminaria japonica seedlings are in the red circle.

[0026] Figure 7Checked on March 16, 2023, the wakame is growing normally, and the kelp seedlings on the breeding ropes have grown to 20 cm.

[0027] Figure 8 The wakame on the breeding ropes at the time of harvest.

[0028] Figure 9 The kelp seedlings remaining on the ropes after the wakame is harvested.

[0029] Figure 10 The small kelp on the breeding ropes at the time of harvest. Detailed implementation manners

[0030] It should be noted that the following detailed descriptions are all illustrative and are intended to provide further explanations for the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0031] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the technical solution of the present application will be described in detail below in conjunction with specific embodiments.

[0032] 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. The experiments in the present invention were carried out in the Baitanzi Sea area of Lushunkou District, Dalian City. The seedling ropes used are vinylon ropes with a diameter of 2 mm containing a small amount of polyethylene filaments, and the breeding ropes are polyethylene ropes with a diameter of 1.8 cm.

[0033] The existing cultivation methods for wakame and kelp are separate cultivation, that is, the sea water area is divided into sections, floating rafts are set up, and both ends of the floating rafts are connected by stem ropes, which is equivalent to enclosing a square area with stem ropes. Inside the square area, floating rafts are set at an 8-meter interval, and both ends of the floating rafts are connected to the floating rafts by weights (or stakes) to stabilize the floating rafts. A square floating raft area is formed on the water surface to cultivate kelp or wakame separately.

[0034] The main production areas of wakame are mainly in Dalian, Liaoning and Rongcheng, Shandong. Seedlings are raised starting from June every year. The indoor seedlings are transferred to the sea area for temporary cultivation around September. In October, the seedlings that reach the seeding specification are clipped onto the breeding ropes and cultured on floating rafts in the sea area. The main harvest period is from February to April of the following year.

[0035] The main production areas of kelp are in Fujian, Shandong and Dalian, Liaoning. The main method for kelp seedling cultivation is to collect zoospores with a seedling rope, cultivate them into seedlings over 1.0 cm indoors, and generally, farmers in Shandong and Dalian transfer the seedlings to the sea area for temporary cultivation in October. In November, when the kelp seedlings on the seedling rope reach about 20 cm, the kelp seedlings are removed and clipped onto the cultivation rope for farming. They are harvested in May-June of the following year. The kelp cultivated in this way is large kelp, with a specification of 3-5 meters in length and weighing several kilograms per plant, which is used for scalding and drying.

[0036] There is also a kind of harvested kelp which is small kelp. When the kelp seedlings are planted in the sea area for temporary cultivation in October, let the kelp seedlings on the seedling rope grow until they reach 50-60 cm in length and then harvest. In recent years, small kelp has been selling well in the market and is mainly used as hot pot ingredients. Large kelp grows on the cultivation rope, with a small density. On an 8-meter-long cultivation rope, about 80 seedlings are clipped. Small kelp is generally directly cultivated with the seedling rope, with a large cultivation density. The number of kelp seedlings per centimeter of the seedling rope can reach 50-100 plants.

[0037] In actual production, farmers conduct kelp seeding on the seedling rope in August. After about 50 days of indoor cultivation in low-temperature seawater, the seedlings grow to more than 1 cm and are transferred to the sea area for temporary cultivation. However, in the present invention, kelp seeding is carried out on the kelp cultivation rope for Undaria pinnatifida a few days before the Undaria pinnatifida seedlings are clipped in October. The cultivation rope is thicker than the seedling rope, but the seeding density of kelp on the cultivation rope is smaller than that on the seedling rope. The number of kelp seedlings finally growing on the cultivation rope in the sea area is 20-50 plants / cm. If it is too small, it will affect the yield; if the seeding density is too large, the small kelp on the later kelp cultivation rope will rot, which will also affect the growth rate and size of the kelp seedlings, and a thinning or thinning method by scraping the seedlings needs to be adopted. Therefore, when conducting kelp seeding, the seeding time is 11-13 h, which is about half of the traditional seeding time. After the cultivation rope collects kelp zoospores, it is fed with flowing water in refrigerated seawater indoors for 1-3 days to enable the kelp zoospores to complete the early development, improve the quality of the kelp seedlings, and then clip the Undaria pinnatifida seedlings and transfer them to the sea area for cultivation.

[0038] If the conventional kelp seedling cultivation mode is adopted, the specifications of the kelp seedlings are not much different from those of the Undaria pinnatifida seedlings when the Undaria pinnatifida seedlings are clipped. The kelp seedlings and the Undaria pinnatifida seedlings grow simultaneously on the cultivation rope. When harvesting the Undaria pinnatifida, the kelp has already grown up, competing with each other, and the growth of kelp and Undaria pinnatifida affects each other. In this seeding mode, the development and growth of kelp are late and do not affect the growth of Undaria pinnatifida. When the Undaria pinnatifida reaches the harvest specification, the kelp seedlings are still very small and do not affect the yield of Undaria pinnatifida.

[0039] Example 1:

[0040] (1) Kelp seeding

[0041] On October 15th, 20 aquaculture seed ropes, each 8 meters long, were immersed in seawater at 9°C. Twenty-seven "Fengbao No. 3" kelp seedlings temporarily raised indoors were air-dried in the air at 19°C for 1.5 hours (see Figure 1 ). If the air-drying temperature is too high, the viability of zoospores will decrease, affecting the effect of spore attachment. If the temperature is too low, it will take too long for air-drying, which is not conducive to production operations. Select 12 seedlings with better sporangia and put them into a 120L white plastic bucket, add 100L of refrigerated seawater at 9°C, and store them in a 9°C water bath (see Figure 2 ). The kelp releases zoospores (see Figure 3 ). Take 200 milliliters of the liquid containing released zoospores, kill the zoospores with iodine solution, shake well, and count with a hemocytometer to detect the density of kelp zoospores in seawater. When the zoospore density reaches 2,200 / ml, remove the seedlings. Put the 20 aquaculture seed ropes soaked in the refrigerated water into a large bucket containing kelp zoospores (see Figure 4 ). After 12 hours, take out the aquaculture seed ropes from the large bucket and put them into a seawater pool with a water temperature of 9°C for temporary cultivation for 3 days. During this period, running water is used to keep the water temperature stable, and the light is controlled at ≤2,000 lx. In this step, the seawater temperature is set at 9°C. At this water temperature, the release and attachment effects of kelp zoospores are good.

[0042] (2) Clamping seedlings of Undaria pinnatifida

[0043] Take 1 curtain of Undaria pinnatifida seedlings from the sea area, cut the seedling ropes into 3-cm small sections, and soak them in a stainless steel basin. Take out the aquaculture seed ropes for collecting kelp seedlings from the pool and clamp the Undaria pinnatifida seedling sections at intervals of about 40 cm (see Figure 5 ). The aquaculture seed ropes are 8 meters long, and each rope is clamped with 20 Undaria pinnatifida seedling sections (20 cm are left at both ends of each aquaculture seed rope for tying the suspension ropes).

[0044] (3) Releasing into the sea area

[0045] The flat cultivation method is adopted. After clamping the seedlings of Undaria pinnatifida, immediately transfer the seed ropes to the floating raft cultivation in the sea area. Hang the seed ropes horizontally between two adjacent floating rafts so that the seed ropes are horizontally suspended in the seawater. The horizontal suspension water layer is about 1.2 m. The distance between the seed ropes is 1.4 m, and the row spacing of the floating rafts is 8 m. For one aquaculture area, there are 31 floating rafts, and 1,800 aquaculture seed ropes are hung for cultivation. After completion, conduct conventional management methods for Undaria pinnatifida cultivation at sea until harvest. When the Undaria pinnatifida grows to 65 ± 5 cm, raise the water layer of the seed ropes from the initially hung 1.2 m to about 0.5 m. One week later, hang small plastic floats (with a diameter of 20 cm) in the middle of the seed ropes to make the water layer in the middle part of the seed ropes about 70 cm.

[0046] (4) Harvesting

[0047] On February 15 of the following year, the wakame was growing normally, and the kelp seedlings had grown to about 2 cm in size. The density of kelp seedlings on the cultivation ropes between the wakame was 33 - 40 plants / cm (see Figure 6 ). On March 16, the wakame was growing normally, and the kelp seedlings on the cultivation ropes had grown to 20 cm (see Figure 7 ).

[0048] On April 21, the wakame was harvested (see Figure 8 ). At this time, most of the wakame had a diameter of 4 - 6 cm and a length of 1.3 - 2 m. The wakame with a diameter of 2.5 cm was harvested, and the wakame below this standard had too low value and was abandoned. The average yield of wakame harvested from each cultivation rope was 178 kg. At this time, only the kelp seedlings remained on the ropes.

[0049] On June 18, the kelp seedlings had grown to 50 - 60 cm (see Figure 9 ), and the small kelp was harvested. The average yield of kelp harvested from each cultivation rope was 28 kg.

[0050] Comparative Example 1: Monoculture of wakame

[0051] On October 19, take the "Haibao No. 2" wakame seedling curtain with a length of 0.5 cm in the sea area for temporary cultivation, cut the seedling curtain rope into 3 - cm small sections, and clip them onto the cultivation rope with a spacing of 40 cm between the clips.

[0052] The flat - cultivation method is adopted. Hang the cultivation rope horizontally between two adjacent floating rafts so that the cultivation rope is horizontally suspended in the sea water. The horizontal suspension water layer is about 1.2 m. The hanging spacing of the cultivation ropes is 1.4 m. For one cultivation unit, there are 31 floating rafts and 1800 cultivation ropes are hung. After completion, carry out the conventional sea - based wakame cultivation management method until harvest.

[0053] When the wakame grows to 65 ± 5 cm, raise the water layer of the cultivation rope from the initial 1.2 m to about 0.5 m. One week later, hang small plastic floats (with a diameter of 20 cm) in the middle of the cultivation rope to make the water layer in the middle part of the cultivation rope about 70 cm.

[0054] On April 21, the wakame was harvested. The wakame with a diameter of 2.5 cm was harvested, and the average yield of wakame per cultivation rope was 181 kg.

[0055] The method of the present invention reasonably arranges the growth cycles of wakame seedlings and kelp seedlings. In the same water body, kelp and wakame are co-cultured starting from October. However, the development and growth of kelp seedlings lag behind that of wakame, which does not affect the growth of wakame. After harvesting wakame from February to April, the kelp continues to grow on the seed ropes. When the kelp grows to a suitable size for harvesting, small kelp is harvested. Before harvesting wakame, the aquaculture management is exactly the same as that of single-cultured wakame, reducing the complexity of daily management operations, reducing the workload, and saving labor costs. This study improves the efficiency and benefits of seaweed aquaculture per unit water body, increases the utilization rate of sea areas, contributes to the aquaculture of kelp and wakame, and has practical application value for marine fishery production.

[0056] The above are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A method for co-culturing Undaria pinnatifida and Laminaria angustata on a breeding seed rope, characterized in that, It includes the following steps: (1) In October, put the air-dried kelp seedlings into a container filled with seawater. When the number of zoospores released by the kelp seedlings in the seawater reaches 2000 - 3000 per milliliter, take out the seedlings, and put the cultivation ropes into the container containing the kelp zoospores for seeding. After seeding, take out the cultivation ropes and temporarily culture them in seawater; (2) When the wakame seedlings on the seedling ropes reach the seeding specification, take out the seedling ropes temporarily cultured in the sea area and cut them into seedling segments of 2 - 5 cm. Take out the temporarily cultured cultivation ropes and clamp the wakame seedling segments on the cultivation ropes at an interval of 30 - 50 cm; (3) Immediately after clamping the wakame seedlings, transfer the cultivation ropes to the sea area for floating raft cultivation; (4) From February to April of the following year, when the width of the wakame stem reaches 2.5 cm, harvest the wakame; continue to raise the kelp seedlings until small kelp is harvested.

2. The method for co-culturing Undaria pinnatifida and Laminaria angustata on a breeding seed rope according to claim 1, characterized in that, In step (1), the kelp seedlings are air-dried in the air at 15 - 20 °C for 1 - 3 hours.

3. The method for co-culturing Undaria pinnatifida and Laminaria angustata on a breeding seedling rope according to claim 1, characterized in that, In step (1), put the air-dried kelp seedlings into a container filled with seawater at 7 - 11 °C, and keep the water temperature at 7 - 11 °C during storage.

4. The method for co-culturing Undaria pinnatifida and Laminaria angustata on a breeding seed rope according to claim 1, characterized in that, In step (1), the cultivation ropes are soaked in seawater at 7 - 11 °C before seeding.

5. The method for co-culturing Undaria pinnatifida and Laminaria angustata on a breeding seed rope according to claim 1, characterized in that, In step (1), 5 - 15 hours after seeding, take out the cultivation ropes and temporarily culture them in flowing seawater at 7 - 11 °C.

6. The method for co-culturing Undaria pinnatifida and Saccharina japonica on a breeding seed rope according to claim 5, characterized in that, Temporarily culture for 2 - 4 days, during which the light intensity ≤ 2000 lx.

7. The method for co-culturing Undaria pinnatifida and Laminaria angustata on a breeding seed rope according to claim 1, wherein In step (3), the distance between floating rafts is 6 - 10 m, the distance between the ropes is 120 - 160 cm, and 50 - 70 cultivation ropes are set per mu of sea surface.

Images