A seawater fertilization method for increasing the yield of oyster culture

Abstract

The present application relates to a kind of sea water fertilization methods for increasing production of oyster culture, comprising the following steps: step S1: oyster is planted in culture area to culture area water transparency reaches 3 meters or more, first nutrient solution is applied to culture area until oyster grows to average shell length exceeds 6cm;Step S2: first nutrient solution or second nutrient solution is applied to culture area, until oyster grows to average shell length exceeds 9cm;Step S3: first nutrient solution or second nutrient solution or third nutrient solution is applied to culture area, until oyster stops fertilization 3-5 days before harvesting;First nutrient solution includes 3.7-5.9g / L basic nutrient and 0.52-1.55mg / L plant growth hormone;Second nutrient solution includes 6.0-8.0g / L basic nutrient and 0.53-1.55mg / L plant growth hormone;Third nutrient solution includes 2.4-2.9g / L basic nutrient and 0.22-0.42mg / L plant growth hormone.The present application can make oyster grow rapidly, improve plumpness, shorten culture period, promote the growth and weight gain of oyster.

Description

Technical Field

[0001] This invention relates to the field of aquaculture, and in particular to a method for fertilizing seawater to increase oyster farming yields. Background Technology

[0002] Oysters are a high-protein, low-fat food, rich in vitamins, minerals, and high-quality protein, making them highly nutritious. They play a significant role in many areas, including maintaining male reproductive health, children's development, preventing osteoporosis in middle-aged and elderly people, maternal and child health, preventing arteriosclerosis, anti-thrombosis, anti-aging, enhancing immune function, and cancer prevention. Oysters are a major aquaculture species, ranking first in global shellfish production and possessing significant economic value. Oyster farming is an important component of my country's fisheries economy. For many years, my country has consistently ranked first in oyster production globally, reaching a record high of over 6 million tons in 2023, accounting for 87% of global production. The oyster industry not only plays a crucial role in national food security and the economic stability of coastal areas but also provides numerous employment opportunities for fishermen and farmers, increasing their income sources.

[0003] Currently, there is no commercially available artificial food for oysters, so oysters still need to rely on natural food (single-celled algae) in seawater for growth. Current oyster farming methods generally employ longline culture. However, these methods involve high stocking densities, and as oysters grow, their filter-feeding capacity and intensity increase, leading to excessive consumption of single-celled algae in the seawater. The reproduction and growth rate of these algae cannot keep up with the oysters' feeding rate and quantity. Simultaneously, high-density farming and intensive filter-feeding result in localized seawater depletion (primarily determined by excessively low chlorophyll concentration in the farming area), a sharp decline in microalgae concentration, and reduced primary productivity. While some oyster farming methods add nutrients to the farming area to promote rapid growth of single-celled algae, the effect on their reproduction is limited and still insufficient to meet the oysters' high-volume filter-feeding needs. Therefore, oysters cultivated using current methods are prone to malnutrition, resulting in slow growth, low plumpness (meat yield), and long farming cycles. Longer farming cycles bring more risks, such as increased oyster seedling detachment rates, reduced yields, and low economic returns due to typhoons. Summary of the Invention

[0004] Based on this, the purpose of this invention is to provide a seawater fertilization method that can increase oyster farming production, promote oyster growth, shorten the oyster farming cycle, and increase the oyster meat yield, thereby producing more high-quality oysters.

[0005] A method for fertilizing seawater to increase oyster farming yields includes the following steps:

[0006] Step S1: When the oysters are stocked in the aquaculture area and cultured until the water transparency of the aquaculture area reaches more than 3 meters, the first nutrient solution is applied to the aquaculture area until the oysters grow to an average shell length of more than 6 cm.

[0007] Step S2: Apply the first nutrient solution or the second nutrient solution to the aquaculture area until the oysters grow to an average shell length of more than 9 cm;

[0008] Step S3: Apply the first nutrient solution, the second nutrient solution, or the third nutrient solution to the aquaculture area until 3-5 days before the oyster harvest, then stop fertilizing.

[0009] The first nutrient solution contains 3.7–5.9 g / L of basic nutrients and 0.52–1.55 mg / L of plant growth hormone; the second nutrient solution contains 6.0–8.0 g / L of basic nutrients and 0.53–1.55 mg / L of plant growth hormone; and the third nutrient solution contains 2.4–2.9 g / L of basic nutrients and 0.22–0.42 mg / L of plant growth hormone.

[0010] Because oysters can efficiently filter seawater and increase water transparency, this invention provides a seawater fertilization method for increasing oyster farming yields. The nutrient solution formula is adjusted based on the water transparency and oyster growth status in the farming area. The first, second, and third nutrient solutions of this invention, in addition to containing basic nutrients, all contain plant growth hormones. These not only better promote the growth rate of single-celled algae in the farming area but also increase their reproduction rate, meeting the oysters' feeding needs. This results in rapid oyster growth, increased plumpness, and a shortened farming cycle, promoting oyster growth and weight gain. Furthermore, the inventors' research has found that excessively low basic nutrient concentrations have limited effect on promoting single-celled algae growth, while excessively high basic nutrient concentrations can easily lead to the proliferation of other algae such as Ulva prolifera and Ulva lactuca, which compete with single-celled algae for nutrients and growth space, thus affecting the growth of single-celled algae in the farming area. Similarly, excessively low levels of plant growth hormones have limited effect on promoting the reproduction of single-celled algae, while excessively high levels inhibit their reproduction and growth. Therefore, limiting the concentration ranges of the aforementioned basic nutrients and plant growth hormones is most beneficial for oyster farming. Based on extensive practical experience and experimental data, the inventors have determined the concentration ranges of basic nutrients and plant growth hormones in the first, second, and third nutrient solutions, which all demonstrate good effects on promoting oyster growth and development.

[0011] Furthermore, the oyster is a diploid larva; the initial culture shell of the oyster in step S1 has a shell length of 1-3 cm and a shell width of 1-1.5 cm.

[0012] Furthermore, the basic nutrients include macroelements, microelements, vitamins, and urine; the macroelements include NaNO3, NaH2PO4, and Na2SiO3·9H2O; the microelements include ZnSO4·7H2O, Cl2Mn·4H2O, CuSO4·5H2O, Na2MoO4·2H2O, and FeC6H5O7·5H2O; the vitamins include VB. 12 The plant growth hormones include VB1 and VH; the plant growth hormones include GA3 gibberellin, 6-BA cytokinin and brassinosteroids.

[0013] Furthermore, the application frequency of the first nutrient solution is:

[0014] (1) When the average shell length of the oyster is <4cm: apply once every 7 to 8 days on average;

[0015] (2) When the average shell length of the oyster is ≥4cm or the chlorophyll a concentration in the culture area is less than 3.0μg / L: apply once every 4 to 5 days on average.

[0016] When the average shell length of oysters is less than 4cm, their individual size is small, and their filter feeding ability and intensity are weak. The fertilization frequency of the first nutrient solution is once every 7-8 days, which can well meet the growth and reproduction needs of single-celled algae. However, after a period of time, when the oysters grow to an average shell length of ≥4cm, their filter feeding ability becomes stronger, and the fertilization frequency of once every 7-8 days for the first nutrient solution is no longer sufficient (specifically manifested by the chlorophyll a value being consistently lower than 3.0μg / L), which cannot meet the oysters' feeding needs for single-celled algae. Therefore, it is necessary to increase the fertilization frequency of the first nutrient solution to once every 4-5 days.

[0017] Furthermore, the second nutrient solution is applied at an average frequency of once every 5 to 7 days.

[0018] Furthermore, the oyster farming method is longline farming.

[0019] Furthermore, the method for applying the first nutrient solution / second nutrient solution is as follows: the basic nutrients and the plant growth hormone are added to seawater and fully dissolved to prepare the first nutrient solution / second nutrient solution; several small bottles with 30 to 40 small holes are prepared, and the first nutrient solution / second nutrient solution is quickly dispensed into the small bottles and sealed; the small bottles are weighted and hung at even intervals under the aquaculture cable, with an average hanging density of one small bottle containing the first nutrient solution / second nutrient solution for every 6 strings of oysters.

[0020] Furthermore, the method for applying the third nutrient solution is as follows: the basic nutrients and the plant growth hormone are added to seawater and fully dissolved to prepare the third nutrient solution; several small bottles with 80-100 small holes are prepared, the third nutrient solution is quickly dispensed into the small bottles and sealed; the small bottles are weighted and hung at even intervals under the aquaculture cable, with an average density of one small bottle containing the third nutrient solution hanging for every two strings of oysters; the application frequency of the third nutrient solution is once every 2-3 days on average.

[0021] Further, in step S2: the second nutrient solution is applied to the aquaculture area. When oysters grow to an average shell length exceeding 6 cm, their filter-feeding ability is further enhanced. As a further improvement to the above scheme, using a second nutrient solution with a higher concentration of basic nutrients can effectively improve seawater fertility, further increasing the growth and reproduction rate of single-celled algae in the aquaculture area, satisfying the oysters' feeding needs, resulting in faster oyster growth, a shorter aquaculture cycle, and higher plumpness. Additionally, it can reduce the frequency of fertilization, thereby reducing labor costs. Based on extensive practical experience and experimental data, the inventors have determined that the concentration range of basic nutrients and plant growth hormones in the second nutrient solution is beneficial for oyster aquaculture. If the concentration and application rate of this second nutrient solution are too low, the oysters will be relatively weak, with limited growth-promoting effects. If the concentration is too high or the application rate is too large, it will cause resource waste and even the proliferation of unwanted algae and other adverse factors.

[0022] Further, in step S3: the third nutrient solution is applied to the aquaculture area. Oysters growing to over 9cm have a stronger filter-feeding ability. Oysters of this size require fattening before market entry, meaning they need richer feed to significantly increase their meat yield. Therefore, a sufficient amount of basic nutrients is needed to better stimulate the growth of single-celled algae. However, due to the larger size of the oysters, they cause greater agitation of the water during filter feeding, leading to more significant water exchange between the aquaculture and non-aquaculture areas. Therefore, fertilization is carried out using a low concentration (diluting the third basic nutrient and the third plant growth hormone into a larger volume of 30-32L of third nutrient solution), high density (the diluted liquid is 30-32L, which can be filled into more small bottles with closer spacing), and high frequency (the small bottles have more holes, allowing for faster exchange with the outside environment, and the fertilization frequency is 2-3 days) to ensure that the applied third nutrient solution acts more efficiently on the aquaculture area.

[0023] To better understand and implement this invention, the following detailed description is provided in conjunction with specific embodiments. Detailed Implementation

[0024] It should be understood that the described embodiments are merely some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of the embodiments of this application.

[0025] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the embodiments of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0026] In the description of this application, it should be understood that the terms "first," "second," "third," etc., are used only to distinguish similar objects and are not necessarily used to describe a specific order or sequence, nor should they be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0027] Furthermore, in the description of this application, unless otherwise stated, "multiple" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0028] A method for fertilizing seawater to increase oyster farming yields includes the following steps:

[0029] Step S1: After the oysters are stocked in the aquaculture area and cultured for 10 to 15 days, the oysters filter the seawater with high intensity so that the water transparency of the aquaculture area reaches more than 3 meters. The first nutrient solution is applied to the aquaculture area and the application frequency is gradually increased until the oysters grow to an average shell length of more than 6 cm.

[0030] Furthermore, the oysters are cultured using longline culture, with an average of 3 strings of oysters per meter; each string contains 30-50 oysters (i.e., 90-150 oysters per meter). The oysters are diploid larvae. The initial cultured shells of the oysters from step S1 have an average shell length of 1-3 cm and an average shell width of 1-1.5 cm. The culture area is a sea area with good water exchange.

[0031] Furthermore, the first nutrient solution contains 3.7–5.9 g / L of a first basic nutrient and 0.52–1.55 mg / L of a first plant growth hormone; the components and content of each component in the first nutrient solution applied to every 100–120 strings of oysters are shown in Table 1 below.

[0032] Further, the method for applying the first nutrient solution is as follows: the first basic nutrient and the first plant growth hormone from Table 1 are added to 10-12L of seawater and fully dissolved to prepare the first nutrient solution; several small plastic bottles with a capacity of more than 500ml are prepared, and 30-40 small holes are pierced in the small plastic bottles with a small needle; the first nutrient solution is quickly dispensed into the small plastic bottles and sealed; the small plastic bottles are weighted and hung at even intervals 20-30cm below the aquaculture cable, with an average hanging density of one small plastic bottle containing the first nutrient solution for every 6 strings of oysters.

[0033] Furthermore, the application frequency of the first nutrient solution is:

[0034] (1) When the average shell length of the oyster is <4cm: apply once every 7 to 8 days on average;

[0035] (2) When the average shell length of the oyster is ≥4cm or the chlorophyll a concentration in the culture area is less than 3.0μg / L: apply once every 4 to 5 days on average.

[0036] Table 1. Composition and content of each component in the first nutrient solution

[0037]

[0038] Step S2: Apply the first nutrient solution or the second nutrient solution to the aquaculture area until the oysters grow to an average shell length of more than 9 cm;

[0039] Furthermore, the second nutrient solution contains 6.0–8.0 g / L of a second basic nutrient and 0.53–1.55 mg / L of a second plant growth hormone; the components and content of each component in the second nutrient solution applied to every 100–120 strings of oysters are shown in Table 2 below.

[0040] Further, the method for applying the second nutrient solution is as follows: the second basic nutrient and the second plant growth hormone from Table 2 are added to 10-12L of seawater and fully dissolved to prepare the second nutrient solution; several small plastic bottles with a capacity of more than 500ml are prepared, and 30-40 small holes are pierced in the small plastic bottles with a small needle; the first nutrient solution is quickly dispensed into the small plastic bottles and sealed; the small plastic bottles are weighted and hung at even intervals 20-30cm below the aquaculture cable, with an average hanging density of one small plastic bottle containing the second nutrient solution for every 6 strings of oysters.

[0041] Furthermore, the second nutrient solution is applied at an average frequency of once every 5 to 7 days.

[0042] Table 2. Components and content of each component in the second nutrient solution

[0043]

[0044] Step S3: Apply the first nutrient solution, the second nutrient solution, or the third nutrient solution to the aquaculture area until 3-5 days before the oyster harvest, then stop fertilizing.

[0045] Furthermore, the third nutrient solution contains 2.4–2.9 g / L of third basic nutrient and 0.22–0.42 mg / L of third plant growth hormone; the components and content of each component in the third nutrient solution applied to every 100–120 strings of oysters are shown in Table 3 below.

[0046] The method for applying the third nutrient solution is as follows: Dissolve the third basic nutrient and the third plant growth hormone from Table 3 in 30-32L of seawater to prepare the third nutrient solution; prepare several small plastic bottles with a capacity exceeding 500ml, and prick 80-100 small holes in each bottle with a needle; quickly dispense the third nutrient solution into the small plastic bottles and seal them; use weights to counterweight the small plastic bottles and hang them evenly at intervals 20-30cm below the aquaculture cable, with an average density of one small plastic bottle containing the third nutrient solution for every 6 oyster strings. The third nutrient solution is applied on average once every 2-3 days.

[0047] Table 3. Components and content of each component in the third nutrient solution

[0048]

[0049]

[0050] Example 1

[0051] This embodiment of a seawater fertilization method for increasing oyster farming yield includes the following steps:

[0052] Step S1: After the oysters are stocked and cultured in the first oyster farming area of ​​Jiaowei Township, Xuwen County, Zhanjiang City for 15 days, when the seawater transparency of the farming area exceeds 3 meters, the first nutrient solution is applied to the farming area and the application frequency is gradually increased.

[0053] In this embodiment, the method for applying the first nutrient solution is as follows: The first basic nutrient and the first plant growth hormone from Table 1 are added to 10L of seawater and fully dissolved to prepare the first nutrient solution; 20 small plastic bottles with a capacity exceeding 500ml are prepared, and 40 small holes are pierced in each bottle using a small needle; the first nutrient solution is quickly dispensed into the small plastic bottles and sealed, with each small plastic bottle containing 500ml of the first nutrient solution; the small plastic bottles are weighted with small stones or other weights, and then hung at even intervals 25-30cm below the aquaculture cable; the hanging density is one small plastic bottle containing the first nutrient solution for every 6 oyster strings on average. The first nutrient solution in the small plastic bottles is replaced every 7 days.

[0054] After 30 days of cultivation, as the oysters grew, their filter feeding intensity increased, and the chlorophyll a concentration in the cultivation area was lower than 2.0 μg / L. The first nutrient solution in the plastic bottle was changed to be replaced every 5 days. After another month of cultivation, the average shell length of the oysters exceeded 6 cm.

[0055] Step S2: Apply the second nutrient solution to the aquaculture area. In this embodiment, the application method of the second nutrient solution is as follows: Add the basic nutrients and plant growth hormones in Table 2 to 10L of seawater and dissolve them thoroughly to prepare the second nutrient solution; prepare 20 small plastic bottles with a capacity of more than 500ml and prick 40 small holes in each small plastic bottle with a small needle; quickly dispense the second nutrient solution into the small plastic bottles and seal them, with each small plastic bottle containing 500ml of the second nutrient solution; use small stones or other weights to weigh the small plastic bottles and then hang them 25-30cm below the aquaculture cable; the hanging density is one small plastic bottle containing the first nutrient solution for every 6 strings of oysters on average; the second nutrient solution in the plastic bottles is changed on average every 6 days; after 2 months of aquaculture, the average shell length of the oysters exceeds 9cm.

[0056] Step S3: Apply the third nutrient solution to the aquaculture area. In this embodiment, the method for applying the third nutrient solution is as follows: Dissolve the third basic nutrient and the third plant growth hormone from Table 3 in 30L of seawater to prepare the third nutrient solution; prepare 60 small plastic bottles with a capacity of more than 500ml each, and prick 80 small holes in each bottle with a needle; quickly dispense the third nutrient solution into the small plastic bottles and seal them, with each small plastic bottle containing 500ml of the third nutrient solution; use small stones or other weights to weigh the small plastic bottles, and then hang them evenly at intervals 25-30cm below the aquaculture cable; the bottle density is one small plastic bottle containing the first nutrient solution for every two strings of oysters. The third nutrient solution in the small plastic bottles is changed every 3 days on average; fertilization is stopped after 6 months of aquaculture, at which time the average fresh weight of the oysters is 300g-350g / oyster, which can meet market demand.

[0057] Five days after fertilization was stopped, the oysters in the aquaculture area were harvested.

[0058] Example 2

[0059] This embodiment of a seawater fertilization method for increasing oyster farming yield includes the following steps:

[0060] Step S1: After the oysters are stocked and cultured in the oyster farming area of ​​Caotan Town, Suixi County, Zhanjiang City for 12 days, when the seawater transparency of the farming area exceeds 3 meters, the first nutrient solution is applied to the farming area and the application frequency is gradually increased.

[0061] In this embodiment, the method of applying the first nutrient solution and the frequency of replacing the first nutrient solution in the plastic bottle are the same as in Embodiment 1.

[0062] After 32 days of cultivation, as the oysters grew, their filter feeding intensity increased, and the chlorophyll a concentration in the cultivation area was lower than 2.0 μg / L. The first nutrient solution in the plastic bottle was changed to be replaced every 5 days. After 40 days of continued cultivation, the average shell length of the oysters exceeded 6 cm.

[0063] Step S2: Apply the second nutrient solution to the aquaculture area; in this embodiment, the second nutrient solution and its application method are the same as in Embodiment 1. The second nutrient solution in the plastic bottle is replaced on average every 5 days; after 2 months of aquaculture, the average shell length of the oysters exceeds 9 cm.

[0064] Step S3: Apply the third nutrient solution to the aquaculture area; the third nutrient solution is the same as in Example 1.

[0065] In this embodiment, the method for applying the third nutrient solution is as follows: The third basic nutrient and the third plant growth hormone from Table 3 are added to 30L of seawater and fully dissolved to prepare the third nutrient solution; 60 small plastic bottles with a capacity exceeding 500ml are prepared, and 90 small holes are pierced in each bottle with a small needle; the third nutrient solution is quickly dispensed into the small plastic bottles and sealed, with each small plastic bottle containing 500ml of the third nutrient solution; the small plastic bottles are weighted with small stones or other weights, and then hung at even intervals 25-30cm below the aquaculture cable; the hanging density is one small plastic bottle containing the first nutrient solution for every two oyster strings. The third nutrient solution in the small plastic bottles is changed on average every 3 days; fertilization is stopped after 6.5 months of aquaculture, at which point the average fresh weight of the oysters is 300g-350g / oyster, which meets market demand.

[0066] Five days after fertilization was stopped, the oysters in the aquaculture area were harvested.

[0067] Example 3

[0068] This embodiment of a seawater fertilization method for increasing oyster farming yield includes the following steps:

[0069] Step S1: After the oysters are stocked and cultured for 18 days in the second oyster farming area of ​​Jiaowei Township, Xuwen County, Zhanjiang City (3-5 km away from the farming area in Example 1), the seawater transparency in the farming area exceeds 3 meters. The first nutrient solution is then applied to the farming area and the application frequency is gradually increased.

[0070] In this embodiment, the method for applying the first nutrient solution is as follows: The first basic nutrient and the first plant growth hormone from Table 1 are added to 10L of seawater and fully dissolved to prepare the first nutrient solution; 20 small plastic bottles with a capacity exceeding 500ml are prepared, and 40 small holes are pierced in each bottle using a small needle; the first nutrient solution is quickly dispensed into the small plastic bottles and sealed, with each small plastic bottle containing 500ml of the first nutrient solution; the small plastic bottles are weighted with small stones or other weights, and then hung at even intervals 30cm below the aquaculture cable; the hanging density is one small plastic bottle containing the first nutrient solution for every 6 oyster strings on average. The first nutrient solution in the small plastic bottles is replaced every 7 days.

[0071] After 30 days of cultivation, as the oysters grow, their filter feeding intensity increases, and the chlorophyll a concentration in the cultivation area is lower than 2.0 μg / L. The first nutrient solution in the plastic bottle is changed to be replaced every 5 days, and cultivation continues until the average shell length of the oysters exceeds 6 cm.

[0072] Step S2: Apply the first nutrient solution to the aquaculture area. The method of applying the first nutrient solution is the same as above. At this time, the first nutrient solution in the plastic bottle is replaced every 4 days. Continue aquaculture until the average shell length of the oysters exceeds 9cm.

[0073] Step S3: Apply the first nutrient solution to the aquaculture area. The method of applying the first nutrient solution is the same as above. At this time, the first nutrient solution in the small plastic bottle is changed every 4 days. Fertilization is stopped when the oysters have been cultured for 8 months. At this time, the average fresh weight of the oysters is 300g to 350g / oyster, which can meet market demand.

[0074] Five days after fertilization was stopped, the oysters in the aquaculture area were harvested.

[0075] Example 4

[0076] This embodiment of a seawater fertilization method for increasing oyster farming yield includes the following steps:

[0077] Step S1: After stocking the oysters in the third oyster farming area of ​​Jiaowei Township, Xuwen County, Zhanjiang City (6-7 km away from the farming area in Example 1) for 17 days, when the seawater transparency of the farming area exceeds 3 meters, the first nutrient solution is applied to the farming area and the application frequency is gradually increased.

[0078] In this embodiment, the method for applying the first nutrient solution is as follows: The first basic nutrient and the first plant growth hormone from Table 1 are added to 10L of seawater and fully dissolved to prepare the first nutrient solution; 20 small plastic bottles with a capacity exceeding 500ml are prepared, and 40 small holes are pierced in each bottle using a small needle; the first nutrient solution is quickly dispensed into the small plastic bottles and sealed, with each small plastic bottle containing 500ml of the first nutrient solution; the small plastic bottles are weighted with small stones or other weights, and then hung at even intervals 30cm below the aquaculture cable; the hanging density is one small plastic bottle containing the first nutrient solution for every 6 oyster strings on average. The first nutrient solution in the small plastic bottles is replaced on average every 7 days.

[0079] After 30 days of cultivation, as the oysters grew, their filter feeding intensity increased, and the chlorophyll a concentration in the cultivation area was lower than 2.0 μg / L. The first nutrient solution in the plastic bottle was changed to be replaced every 5 days. After another month of cultivation, the average shell length of the oysters exceeded 6 cm.

[0080] Step S2: Apply the second nutrient solution to the aquaculture area. In this embodiment, the application method of the second nutrient solution is as follows: Dissolve the second basic nutrient and the second plant growth hormone from Table 2 in 10L of seawater to prepare the second nutrient solution; prepare 20 small plastic bottles with a capacity of more than 500ml, and prick 40 small holes in each bottle with a needle; quickly dispense the second nutrient solution into the small plastic bottles and seal them, with each small plastic bottle containing 500ml of the second nutrient solution; use small stones or other weights to weigh the small plastic bottles, and then hang them evenly at intervals 30cm below the aquaculture cable; the bottle density is one small plastic bottle containing the first nutrient solution for every 6 strings of oysters on average. The second nutrient solution in the plastic bottles is replaced on average every 6 days; continue aquaculture until the average shell length of the oysters exceeds 9cm.

[0081] Step S3: Apply the second nutrient solution to the aquaculture area. The method for applying the second nutrient solution is the same as above; the second nutrient solution in the small plastic bottle is replaced on average every 6 days; fertilization is stopped when the oysters have been cultured for 7 months. At this time, the average fresh weight of the oysters is 300g-350g / oyster, which can meet market demand.

[0082] Five days after fertilization was stopped, the oysters in the aquaculture area were harvested.

[0083] Comparative Example 1

[0084] An existing oyster farming method: oysters are released into a farming area and naturally cultured until the average fresh weight of the oysters reaches 300g to 350g / oyster.

[0085] Furthermore, the oysters are cultured using longline culture, with an average of 3 strings of oysters per meter; each string contains 30-50 oysters (i.e., 90-150 oysters per meter). The oysters are diploid larvae. The initial cultured shells of the oysters from step S1 have an average shell length of 1-3 cm and an average shell width of 1-1.5 cm. The culture area is a sea area with good water exchange.

[0086] Comparative Example 2

[0087] An existing oyster farming method involves releasing oyster seedlings into a farming area and allowing them to naturally grow for 8 months.

[0088] Furthermore, the oysters are cultured using longline culture, with an average of 3 strings of oysters per meter; each string contains 30-50 oysters (i.e., 90-150 oysters per meter). The oysters are diploid larvae. The initial cultured shells of the oysters from step S1 have an average shell length of 1-3 cm and an average shell width of 1-1.5 cm. The culture area is a sea area with good water exchange.

[0089] The oyster farming effects of Examples 1-4 and Comparative Examples 1-2 are shown in Table 4 below:

[0090] Table 4

[0091]

[0092] Meat yield = Fresh weight of oyster meat / Total fresh weight of oysters * 100%.

[0093] The oysters in Example 1 had an average fresh weight of 300-350g / oyster, which was 67% higher than the average weight of oysters that were not fertilized during the same period. The meat yield exceeded 25%, achieving excellent quality and meeting market demand. The oyster farming cycle in this example was 6 months, which shortened the farming cycle by 3 months compared to Comparative Example 1, which also used an average fresh weight of 300-350g / oyster as the farming standard. Compared to Comparative Example 2, which also used a farming period of 6 months as the farming standard, the average fresh weight and meat yield of the oysters were significantly improved. Furthermore, the average chlorophyll a content was 8.7μg / L throughout the farming period, indicating sufficient seawater fertility in the farming area.

[0094] The oysters in Example 2 had an average fresh weight of 300-350g / oyster, which was 66% higher than the average weight of oysters that were not fertilized during the same period. The meat yield exceeded 24%, achieving excellent quality and meeting market demand. The oyster farming cycle in this example was 6.5 months, which was 2.5 months shorter than that in Comparative Example 1, which also used an average fresh weight of 300-350g / oyster as the farming standard. Furthermore, the average chlorophyll a content was 8.8μg / L throughout the farming period, indicating sufficient seawater fertility in the farming area.

[0095] The oysters in Example 3 had an average fresh weight of 300-350g / oyster, which was 23% heavier than the oysters that were not fertilized during the same period. The meat yield was over 23%, which is of excellent quality and can meet market demand. The oyster farming cycle in this example was 8 months, which is 1 month shorter than that in Comparative Example 1, which also used an average fresh weight of 300-350g / oyster as the farming standard. However, the average chlorophyll a content during the farming week was less than 1μg / L, and the fertility was significantly insufficient in the later stage. The weight gain and the shortened farming cycle of the oysters farmed in Example 3 were not as good as those in Examples 1 and 2.

[0096] In Example 4, the average fresh weight of the oysters was 300-350g / oyster, representing a 33% increase compared to oysters grown without fertilizer during the same period. The meat yield exceeded 23%, achieving excellent quality and meeting market demand. The oyster cultivation cycle in this example was 7 months, which, compared to Comparative Example 1 (which also used an average fresh weight of 300-350g / oyster), shortened the cultivation cycle by 2 months and showed a significant weight gain. In Example 4, during step S2, the average chlorophyll a level in the cultivation area reached 3.6 μg / L, while during step S3, the average chlorophyll a level did not exceed 1.2 μg / L, indicating a significant improvement in fertility compared to Example 3. However, compared to Examples 1 and 2, the oyster fertility in Example 4 was significantly insufficient. Therefore, the weight gain and shortened cultivation cycle of this example were better than Example 3, but not as good as Examples 1 and 2.

[0097] Compared to existing oyster farming methods, this invention, based on long-term practical experience, proposes a seawater fertilization method to increase oyster production. The nutrient solution formula is adjusted according to the water transparency and oyster growth status in the farming area. By applying a nutrient solution containing basic nutrients and plant growth hormones to the seawater, the reproduction and growth of phytoplankton are effectively enhanced, thereby increasing primary productivity, meeting the oysters' feeding needs, promoting oyster growth, increasing oyster growth rate, shortening the farming cycle, and thus increasing the economic benefits for farmers. Furthermore, the filter feeding of oysters produces a large amount of feces and pseudofeces, increasing the rate and efficiency of organic carbon sequestration in the anaerobic environment of the seabed, forming a virtuous cycle. This promotes the absorption of carbon dioxide from the atmosphere by seawater, resulting in a significant negative carbon flux.

[0098] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and the present invention also intends to include these modifications and variations.

Claims

1. A method for fertilizing seawater to increase oyster farming yield, characterized in that: Includes the following steps: Step S1: When oysters are stocked and cultured in the aquaculture area until the water transparency of the aquaculture area reaches more than 3 meters, the first nutrient solution is applied to the aquaculture area and the application frequency is gradually increased until the oysters grow to an average shell length of more than 6 cm; the aquaculture area is a sea area with smooth water exchange. Step S2: Apply a second nutrient solution to the aquaculture area until the oysters grow to an average shell length of more than 9 cm; Step S3: Apply the third nutrient solution to the aquaculture area until 3-5 days before the oyster harvest, then stop fertilizing. The first nutrient solution contains 3.7–5.9 g / L of basic nutrients and 0.52–1.55 mg / L of plant growth hormone; the second nutrient solution contains 6.0–8.0 g / L of basic nutrients and 0.53–1.55 mg / L of plant growth hormone; the third nutrient solution contains 2.4–2.9 g / L of basic nutrients and 0.22–0.42 mg / L of plant growth hormone; the basic nutrients include macronutrients, micronutrients, vitamins, and urine; the macronutrients include NaNO3, NaH2PO4, and Na2SiO3·9H2O; the micronutrients include ZnSO4·7H2O, Cl2Mn·4H2O, CuSO4·5H2O, Na2MoO4·2H2O, and FeC6H5O7·5H2O; the vitamins include VB. 12 VB1 and VH; the plant growth hormones include GA3 gibberellin, 6-BA cytokinin and brassinosteroids; The components and content of each component in the first nutrient solution The application frequency of the first nutrient solution is: (1) When the average shell length of the oyster is <4cm: apply once every 7 to 8 days on average; (2) When the average shell length of the oyster is ≥4cm or the chlorophyll a concentration in the culture area is less than 3.0μg / L: apply once every 4 to 5 days on average; Composition and content of each component in the second nutrient solution The second nutrient solution is applied once every 5 to 7 days on average. The components and content of each component in the third nutrient solution The third nutrient solution is applied once every 2 to 3 days on average.

2. The seawater fertilization method for increasing oyster farming yield according to claim 1, characterized in that: The oysters are diploid larvae; the initial culture shells of the oysters in step S1 have a shell length of 1-3 cm and a shell width of 1-1.5 cm.

3. The seawater fertilization method for increasing oyster farming yield according to claim 1, characterized in that: The oyster farming method described is longline farming.

4. The seawater fertilization method for increasing oyster farming yield according to claim 1, characterized in that: The method for applying the first nutrient solution / second nutrient solution is as follows: the basic nutrients and the plant growth hormone are added to seawater and fully dissolved to prepare the first nutrient solution / second nutrient solution; several small bottles with 30 to 40 small holes are prepared, and the first nutrient solution / second nutrient solution is quickly dispensed into the small bottles and sealed; the small bottles are weighted and hung at even intervals under the aquaculture cable, with an average hanging density of one small bottle containing the first nutrient solution / second nutrient solution for every 6 strings of oysters.

5. The seawater fertilization method for increasing oyster farming yield according to claim 1, characterized in that: The method for applying the third nutrient solution is as follows: the basic nutrients and the plant growth hormone are added to seawater and fully dissolved to prepare the third nutrient solution; several small bottles with 80 to 100 small holes are prepared, the third nutrient solution is quickly dispensed into the small bottles and sealed; the small bottles are weighted and hung at even intervals under the aquaculture cable, with an average hanging density of one small bottle containing the third nutrient solution for every two strings of oysters.

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