A method for polyculture of Australian blue swamp crayfish and red swamp crayfish in rice paddies

Abstract

This invention discloses a method for polyculture of Australian blue swamp crayfish and red claw crayfish in rice paddies. The method includes the following steps: S1. Engineering modification of the rice paddy and laying of pheromone adsorption media; S2. Differentiated release of crayfish larvae; S3. Periodic induction management based on molting synchronization; S4. Pheromone interference and photobehavioral regulation; S5. Co-harvesting. The polyculture method for Australian blue swamp crayfish and red claw crayfish provided by this invention can significantly reduce interspecific cannibalism, achieving survival rates of over 74.5% and 67.2% for the two crayfish species, respectively, and increasing the comprehensive output value per mu (unit of land area) by 60% to 130%, thus realizing high-value and efficient co-cultivation of crayfish in rice paddies.

Description

Technical Field

[0001] This invention belongs to the field of aquaculture and agricultural ecological farming integration technology, specifically relating to a method for polyculture of Australian blue lobster and red lobster in rice paddies. Background Technology

[0002] Australian blue lobster ( Cherax destructor ) and red swamp crayfish ( Cherax quadricarinatus Both species are high-value large freshwater crayfish. Rice-crayfish co-cultivation in paddy fields is an effective model for improving the overall yield of paddy fields. However, when the two are directly co-cultured, the strong territorial behavior, food competition, and cannibalism during molting often lead to inhibited growth of red claw crayfish and low survival rate of blue claw crayfish, resulting in an overall yield far lower than that of monoculture. Existing technologies mainly address this through physical isolation or single-species farming, but fail to address the underlying behavioral and physiological mechanisms of the crayfish themselves to achieve truly complementary ecological niche co-culture.

[0003] Therefore, there is an urgent need for a mixed-culture technology that can significantly reduce interspecific aggression and improve the survival rate and growth synchronization of mixed-culture. Summary of the Invention

[0004] This invention addresses the problems of existing technologies by providing a technical method for the co-culture of Australian blue swamp crayfish and red swamp crayfish in rice paddies. Its core innovation lies in: eliminating attack signals through the dynamic adsorption and degradation of pheromones; utilizing exogenous molting hormones to periodically induce overlapping molting time windows between the two species, thereby reducing the risk of cannibalism; and combining this with behavioral domestication using specific wavelengths of light to suppress daily fighting. These three factors work synergistically to overcome the interspecies exclusion barrier.

[0005] To achieve the above objectives, the present invention provides a method for polyculture of Australian blue swamp crayfish and red swamp crayfish in rice paddies, specifically including the following steps: S1. Engineering transformation of paddy fields and laying of pheromone adsorption media: Dig an "L"-shaped ring ditch around the paddy field (1.2-1.5 m wide and 0.6-0.8 m deep). Lay a 5-8 cm thick composite adsorption matrix composed of rice husk biochar and zeolite (mass ratio 3:1) at the bottom of the ditch to continuously adsorb alarm and attack pheromones released by shrimp. At the same time, hang a set of retractable porous ceramic shrimp nests every 5 meters above the ring ditch. The shrimp nests are pre-filled with palm flakes soaked in astaxanthin solution. S2. Differentiated release of shrimp larvae by size: 10-15 days after rice transplanting and recovery, red claw crayfish larvae with an average weight of 2.5±0.3 g were first released at a density of 4000-5000 larvae / mu; 7 days later, Australian blue claw crayfish larvae with an average weight of 1.2±0.2 g were released at a density of 2000-2500 larvae / mu; both types of larvae were soaked in water containing 0.5% β-glucan for 10 minutes before release. S3. Periodic induced management based on molting synchronization: Starting from the 20th day after all shrimp larvae have been released, molting synchronization induction will be performed every 30 days: a. At 18:00 in the evening, 20-hydroxyecdysone solution was sprayed into the entire paddy field to achieve a final concentration of 0.08-0.12 mg / L in the water. b. Simultaneously raise the paddy field water temperature by 2.5℃ within 2 hours through a shallow water circulation system and maintain it for 48 hours; c. Feed high-energy compound feed for 3 consecutive days; Through the above process, crayfish with two different genetic backgrounds can complete molting within 48-72 hours, which greatly reduces the probability of cannibalism caused by asynchronous molting. S4. Pheromone interference and regulation of light behavior: During the non-induced molting period, every 5 days, at 9:00-10:00 AM, a β-cyclodextrin aqueous solution with a mass fraction of 0.05%-0.1% (at a rate of 10 L / mu) is evenly sprayed into the water to encapsulate and remove residual interspecific aggression pheromones in the water. At the same time, at night (7:30 PM to 5:00 AM the next day), a red LED light strip with a wavelength of 620-630 nm suspended above the ring ditch is turned on with a light intensity of 15-20 lx to suppress the visually induced aggression behavior of crayfish and guide them to enter the crayfish nest to roost. S5. Collaborative Harvest: The breeding cycle is 120-150 days. When the average weight of Australian blue swamp crayfish reaches more than 50 g and the average weight of red swamp crayfish reaches more than 80 g, the method of first flooding and then slowly lowering the water level is adopted: the water level of the paddy field is raised to 30 cm and maintained for 6 hours, and then the water is drained at a rate of 5 cm per hour. Taking advantage of the difference in stress response of the two types of crayfish to different water flow rates (blue swamp crayfish first swims upstream), blue swamp crayfish are caught with traps in the early stage of drainage (the first 2 hours), and red swamp crayfish are caught in the later stage.

[0006] Compared with the prior art, the present invention has the following outstanding innovations and beneficial effects: For the first time, a three-in-one polyculture regulation system of pheromone interference, molting synchronization, and red light behavior domestication was proposed, which solved the core obstacle of interspecies crayfish polyculture—interspecies aggression and molting asynchrony.

[0007] A creative application of β-cyclodextrin aqueous solution to dynamically remove interspecies pheromones replaces traditional physical isolation, cutting off the attack trigger at the chemical communication level.

[0008] Using exogenous 20-hydroxyecdysone combined with precise temperature difference stimulation, the molting windows of two shrimp species with different growth rates and sexual maturity cycles were forcibly aligned. This method has not been reported domestically or internationally.

[0009] The discovery and utilization of the behavioral inhibition effect of red light at night has significantly reduced nighttime fighting (experiments show that the frequency of fighting has decreased by 67%).

[0010] The method for polyculture of Australian blue swamp crayfish and red swamp crayfish in rice paddies provided by this invention can achieve a survival rate of over 74.5% and 67.2% for the two species, respectively. The comprehensive output value per mu is increased by 60%-130% compared to monoculture, and no prohibited drugs are used, which fully meets the requirements of green and organic agriculture.

[0011] Example 1 At the rice-Australian dragon co-cultivation base of Shanghai Daoshangbang Planting and Breeding Professional Cooperative, a standardized paddy field with an area of ​​2 mu was selected.

[0012] Please provide the source of the following materials or reagents: Australian blue swamp crayfish larvae and red swamp crayfish larvae: Shanghai Xinsheng Aquaculture Professional Cooperative Rice husk biochar: Nanmin Fishing Tackle Shop, Fengxian District, Shanghai Zeolite: Nanmin Fishing Tackle Shop, Fengxian District, Shanghai Porous ceramic shrimp nest: Nanmin Fishing Tackle Shop, Fengxian District, Shanghai Astaxanthin solution: Taobao Fisherman's Doctor, undiluted solution Palm flakes: Commonly available commercial products β-glucan: Sinopharm Chemical Reagent Co., Ltd. 20-Hydroxyecdysone solution: Shanghai Yuanye Biotechnology Co., Ltd. High-energy compound feed (containing 2% shell powder and 1.5% cholesterol): Hubei Zhaoliang Feed Co., Ltd. β-Cyclodextrin: Sinopharm Chemical Reagent Co., Ltd. Follow these steps and requirements to conduct mixed farming of Australian blue crayfish and red crayfish in rice paddies: S1. Engineering transformation of paddy fields and laying of pheromone adsorption media: Dig an "L"-shaped ring ditch around the paddy field (1.2-1.5 m wide and 0.6-0.8 m deep). Lay a 5-8 cm thick composite adsorption matrix composed of rice husk biochar and zeolite (mass ratio 3:1) at the bottom of the ditch to continuously adsorb alarm and attack pheromones released by shrimp. At the same time, hang a set of retractable porous ceramic shrimp nests every 5 meters above the ring ditch. The shrimp nests are pre-filled with palm flakes soaked in astaxanthin solution. S2. Differentiated release of shrimp larvae by size: Ten to fifteen days after the rice transplanters have turned green, on June 15, 2025, 2,500 red claw crayfish larvae (average 2.6 g) per mu were released; on June 22, 2025, 1,500 Australian blue claw crayfish larvae (average 1.2 g) per mu were released. Both types of shrimp larvae were soaked in an aqueous solution containing 0.5% (by weight) β-glucan for 10 minutes before being released; S3. Periodic induced management based on molting synchronization: Starting from the 20th day after all shrimp larvae have been released, molting synchronization induction will be performed every 30 days: Specifically, molting synchronization was carried out on July 12, August 11, and September 10 (0.1 mg / L of 20-hydroxyecdysone aqueous solution, with a temperature increase of 2.5°C). a. At 18:00 in the evening, spray the entire paddy field with 20-hydroxyecdysone solution to make the final concentration of 20-hydroxyecdysone in the water 0.08-0.12 mg / L; b. Simultaneously raise the paddy field water temperature by 2.5℃ within 2 hours through a shallow water circulation system and maintain it for 48 hours; c. Feed high-energy compound feed for 3 consecutive days; Through the above process, crayfish with two different genetic backgrounds can complete molting within 48-72 hours, which greatly reduces the probability of cannibalism caused by asynchronous molting. S4. Pheromone interference and regulation of light behavior: During the non-induced molting period, every 5 days, at 9:00-10:00 AM, a β-cyclodextrin aqueous solution with a mass fraction of 0.05-0.1% (at a rate of 10 L / mu) is evenly sprayed into the water to encapsulate and remove residual interspecific aggression pheromones in the water. At the same time, at night (7:30 PM to 5:00 AM the next day), the red LED light strip (630 nm red light, light intensity 18 lx) suspended above the ring ditch is turned on to use red light to inhibit the visually stimulated aggression behavior of crayfish and guide them to enter the crayfish nest to roost. S5. Collaborative Harvest: The breeding cycle is 120-150 days. When the average weight of Australian blue swamp crayfish reaches more than 50 g and the average weight of red swamp crayfish reaches more than 80 g, the method of first flooding and then slowly lowering the water level is adopted: the water level of the paddy field is raised to 30 cm and maintained for 6 hours, and then the water is drained at a rate of 5 cm per hour. Taking advantage of the difference in stress response of the two types of crayfish to different water flow rates (blue swamp crayfish first swims upstream), blue swamp crayfish are caught with traps in the early stage of drainage (the first 2 hours), and red swamp crayfish are caught in the later stage.

[0013] The specific harvest time was October 20th. The yield of blue lobster was 63 kg per mu, with an average individual weight of 54 g and a survival rate of 74.5%; the yield of red lobster was 145 kg per mu, with an average individual weight of 86 g and a survival rate of 67.2%; the yield of rice was 412 kg per mu, which was not significantly different from the yield of rice.

[0014] The net profit per mu reached 8,650 yuan, which was significantly higher than the control (the profit per mu for monoculture of blue lobster was 3,800 yuan, and the profit per mu for monoculture of red lobster was 5,100 yuan).

Claims

1. A method for polyculture of Australian blue swamp crayfish and red swamp crayfish in rice paddies, characterized in that... Includes the following steps: S1. Engineering transformation of paddy fields and laying of pheromone adsorption media: An "L"-shaped ring ditch was dug around the paddy field. A composite adsorption matrix composed of rice husk biochar and zeolite was laid at the bottom of the ditch, with a thickness of 5-8 cm. At the same time, a set of liftable porous ceramic shrimp nests was suspended every 5 meters above the ring ditch. Palm sheets soaked in astaxanthin solution were placed in the shrimp nests. S2. Differentiated release of shrimp larvae by size: 10-15 days after rice transplanting and recovery, red claw crayfish larvae with an average weight of 2.5±0.3 g were first released at a density of 2000-2500 larvae / mu; 7 days later, Australian blue claw crayfish larvae with an average weight of 1.2±0.2 g were released at a density of 1000-1500 larvae / mu; both types of larvae were soaked in water containing 0.5% β-glucan for 10 minutes before release. S3. Periodic induced management based on molting synchronization: Starting from the 20th day after all shrimp larvae have been released, molting synchronization induction will be performed every 30 days: a. At 18:00 in the evening, spray the entire paddy field with 20-hydroxyecdysone solution to make the final concentration of 20-hydroxyecdysone in the water 0.08-0.12 mg / L; b. Simultaneously raise the paddy field water temperature by 2.5℃ within 2 hours through a shallow water circulation system and maintain it for 48 hours; c. Feed high-energy compound feed for 3 consecutive days; S4. Pheromone interference and regulation of light behavior: During the non-induced molting period, every 5 days, spray a 0.05-0.1% β-cyclodextrin aqueous solution into the water body between 9:00-10:00 AM, at a rate of 10 L / mu; at the same time, at night, from 7:30 PM to 5:00 AM the next day, turn on the red LED light strip with a wavelength of 620-630 nm suspended above the ring ditch, with a light intensity of 15-20 lx; S5. Collaborative Harvest: The breeding cycle is 120-150 days. When the average weight of Australian blue swamp crayfish reaches more than 50 g and the average weight of red swamp crayfish reaches more than 80 g, the method of first flooding and then slowly lowering the water level is adopted: the water level of the paddy field is raised to 30 cm and maintained for 6 hours, and then the water is drained at a rate of 5 cm per hour. Blue swamp crayfish are caught with traps 2 hours before the drainage, and red swamp crayfish are caught later.

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