Penaeus vannamei is native to the waters of the South Pacific coast and is most concentrated in the Ecuadorian coast. It is one of the world's three highest-quality aquaculture species. It has strong disease resistance, rapid growth, long survival time from the water, can adapt to low salinity growth, delicious meat quality, low demand for feed protein, and easy intensive cultivation. At present, China's coastal provinces have started the cultivation of white shrimps in South America and began to promote them to inland waters. Researchers at the College of Fisheries of Zhanjiang Ocean University conducted a study on the tolerable salinity and desalination rate, desalination effect and aquaculture efficacy of P. vannamei. The following research results provide technical references for the breeding of Penaeus vannamei and the promotion of aquaculture in inland waters.
First, the results of the study
1. The effect of salinity change on the survival rate of Penaeus vannamei. Through the salt tolerance test of P. vannamei, the results showed that P. vannamei still showed a high survival rate in low salinity and even in freshwater, and there was no significant difference from the control group. The experimental observation found that with the change of salinity, Penaeus vannamei did not show obvious uncomfortable reactions, and its activity and feeding were normal. 2. The effect of desalination rate on the survival rate of Penaeus vannamei. The results of the dilution speed test of the Penaeus vannamei showed that nine shrimps were diluted from the proportion of 1018 to 1000 with 9 kinds of desalination rate. In addition to the rapid decline of the survival rate below 12 hours, the survival rate was lower, and more than 18 hours can be achieved by gradually diluting. The survival rate was not significantly different from the control group. 3. Comparison of breeding effects of white shrimp in South America in desalinated ponds. Experiments comparing the effects of Penaeus vannamei culture in freshwater ponds of different salinities showed that in the completely freshwater ponds, the size, yield, and survival rate of Penaeus vannamei out of pond were poor; the freshwater ponds with different salinities were There was no significant difference in the size, yield, feed coefficient, and survival rate of P. vannamei out of ponds, but there was a significant growth advantage compared to ponds that had completely freshwater. This shows that Penaeus vannamei can normally live in an environment similar to fresh water.
Second, the problem
1, through the desalination test can be seen during the Penaeus vannamei's larvae during the gradual reduction of seawater salinity to reduce it to a specific gravity of 1000 water environment, in the entire process of desalination shrimp no abnormal activity There was no change in the response, and there was no significant difference in the survival rate of the desalted shrimp seedlings from the non-dilution control group. Even if it is diluted to fresh water, the survival rate of Penaeus vannamei remains high. Penaeus vannamei is a low-salt-resistant shrimp species, and its planktonic larvae are mainly distributed in the low salt water areas near the estuarine area and the coastal lagoon. Penaeus vannamei has a strong ability to regulate osmotic pressure and maintain its osmotic pressure regulation mechanism through ion regulation. In this experiment, desalination was performed by adding fresh water to the original seedling water, and even if the specific gravity was 1000, there was still a small amount of potassium, sodium, calcium, and magnesium ions in the seawater, and thus the water was diluted to When the specific gravity is 1000, Penaeus vannamei can still maintain the normal living conditions by maintaining the balance of internal and external media through its own osmotic pressure adjustment mechanism.
2. From the desalination rate test, it was found that the Penaeus vannamei larvae were diluted to tolerance to salinity within 18 hours, and the survival rate was low. When the salinity was decreased by 0001 per hour, the survival rate of Penaeus vannamei was not significantly different from that of the non-dilution control group. This may be due to the fact that Penaeus vannamei gradually adjusts to the environment during the longer desalination period and can regulate its own osmotic pressure. The trial observed that the faster the speed of desalination was, the majority of trial prawn first traveled along the barrel edge, and then the leaner barrels were found to be less vigorous. The activity was significantly reduced, and the activities of the trial larvae in the barrels that gradually faded over 18 hours were similar to those of feeding. There was no significant difference in the control group. Therefore, it can be considered that the control of the desalination rate of P. vannamei is safe under the salinity of 0001 per hour. 3. Comparison of the results of the experiment on the cultivation of Penaeus vannamei from freshwater ponds showed that in the freshwater ponds without added seawater or crude salt, the early mortality rate of Penaeus vannamei in stocking was higher, the growth was slower, and the feed coefficient was higher. In the pond with a specific gravity of 1000, Penaeus vannamei was cultured. Although the water environment was similar to freshwater, the growth rate, feed coefficient, and survival rate of Penaeus vannamei performed well. Some researchers pointed out that when the proportion of seawater dropped to 1000, the growth rate of P. vannamei decreased significantly. There was no stage comparison in this experiment, but it was found during the breeding process that the white shrimp died quickly from the water in the low specific gravity pond, the shrimp shell was thin, and the shrimp transportation was difficult. It is worth noting that in one of the freshwater ponds, although the seawater was not deployed but artificial seawater was regularly applied, the growth of the shrimps was normal. Therefore, the cultivation of Penaeus vannamei in inland ponds, regular addition of a certain amount of seawater to the water body, or the addition of raw salt or the addition of minerals to the diet, is the key to ensuring the success of Penaeus vannamei breeding.
First, the results of the study
1. The effect of salinity change on the survival rate of Penaeus vannamei. Through the salt tolerance test of P. vannamei, the results showed that P. vannamei still showed a high survival rate in low salinity and even in freshwater, and there was no significant difference from the control group. The experimental observation found that with the change of salinity, Penaeus vannamei did not show obvious uncomfortable reactions, and its activity and feeding were normal. 2. The effect of desalination rate on the survival rate of Penaeus vannamei. The results of the dilution speed test of the Penaeus vannamei showed that nine shrimps were diluted from the proportion of 1018 to 1000 with 9 kinds of desalination rate. In addition to the rapid decline of the survival rate below 12 hours, the survival rate was lower, and more than 18 hours can be achieved by gradually diluting. The survival rate was not significantly different from the control group. 3. Comparison of breeding effects of white shrimp in South America in desalinated ponds. Experiments comparing the effects of Penaeus vannamei culture in freshwater ponds of different salinities showed that in the completely freshwater ponds, the size, yield, and survival rate of Penaeus vannamei out of pond were poor; the freshwater ponds with different salinities were There was no significant difference in the size, yield, feed coefficient, and survival rate of P. vannamei out of ponds, but there was a significant growth advantage compared to ponds that had completely freshwater. This shows that Penaeus vannamei can normally live in an environment similar to fresh water.
Second, the problem
1, through the desalination test can be seen during the Penaeus vannamei's larvae during the gradual reduction of seawater salinity to reduce it to a specific gravity of 1000 water environment, in the entire process of desalination shrimp no abnormal activity There was no change in the response, and there was no significant difference in the survival rate of the desalted shrimp seedlings from the non-dilution control group. Even if it is diluted to fresh water, the survival rate of Penaeus vannamei remains high. Penaeus vannamei is a low-salt-resistant shrimp species, and its planktonic larvae are mainly distributed in the low salt water areas near the estuarine area and the coastal lagoon. Penaeus vannamei has a strong ability to regulate osmotic pressure and maintain its osmotic pressure regulation mechanism through ion regulation. In this experiment, desalination was performed by adding fresh water to the original seedling water, and even if the specific gravity was 1000, there was still a small amount of potassium, sodium, calcium, and magnesium ions in the seawater, and thus the water was diluted to When the specific gravity is 1000, Penaeus vannamei can still maintain the normal living conditions by maintaining the balance of internal and external media through its own osmotic pressure adjustment mechanism.
2. From the desalination rate test, it was found that the Penaeus vannamei larvae were diluted to tolerance to salinity within 18 hours, and the survival rate was low. When the salinity was decreased by 0001 per hour, the survival rate of Penaeus vannamei was not significantly different from that of the non-dilution control group. This may be due to the fact that Penaeus vannamei gradually adjusts to the environment during the longer desalination period and can regulate its own osmotic pressure. The trial observed that the faster the speed of desalination was, the majority of trial prawn first traveled along the barrel edge, and then the leaner barrels were found to be less vigorous. The activity was significantly reduced, and the activities of the trial larvae in the barrels that gradually faded over 18 hours were similar to those of feeding. There was no significant difference in the control group. Therefore, it can be considered that the control of the desalination rate of P. vannamei is safe under the salinity of 0001 per hour. 3. Comparison of the results of the experiment on the cultivation of Penaeus vannamei from freshwater ponds showed that in the freshwater ponds without added seawater or crude salt, the early mortality rate of Penaeus vannamei in stocking was higher, the growth was slower, and the feed coefficient was higher. In the pond with a specific gravity of 1000, Penaeus vannamei was cultured. Although the water environment was similar to freshwater, the growth rate, feed coefficient, and survival rate of Penaeus vannamei performed well. Some researchers pointed out that when the proportion of seawater dropped to 1000, the growth rate of P. vannamei decreased significantly. There was no stage comparison in this experiment, but it was found during the breeding process that the white shrimp died quickly from the water in the low specific gravity pond, the shrimp shell was thin, and the shrimp transportation was difficult. It is worth noting that in one of the freshwater ponds, although the seawater was not deployed but artificial seawater was regularly applied, the growth of the shrimps was normal. Therefore, the cultivation of Penaeus vannamei in inland ponds, regular addition of a certain amount of seawater to the water body, or the addition of raw salt or the addition of minerals to the diet, is the key to ensuring the success of Penaeus vannamei breeding.
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