A strain selection method for omnivorous largemouth bass

Abstract

The present invention discloses a strain selection method for omnivorous largemouth black bass, and relates to aquatic product variety improvement technology. Newly hatched largemouth black bass fry are placed in a fry breeding pond for breeding; during screening, the selected individuals are semi-starved and fed so that the carnivorous individuals eat other individuals; the carnivorous individuals are screened out; the unscreened individuals are fed with synthetic feed until all the individuals grow into adult fish; the adult fish are cultivated and bred as parents to obtain a new generation of largemouth black bass fry; the obtained largemouth black bass fry are used as new seedlings, and the above breeding and screening method is repeated at least twice; the largemouth black bass fry obtained in the last time are used as target fry. The selection method of the present invention is simple and convenient, and the selection effect is direct. It not only plays a role in improving the overall quality of the group and realizing the improvement of the fry, but also can reduce the phenomenon of cannibalism and improve the survival rate.

Description

Technical Field

[0001] The invention relates to aquatic product variety improvement technology, and more specifically, to a strain selection method for omnivorous largemouth black bass. Background Art

[0002] In nature, there are fish with different feeding habits. Such as carnivorous fish, herbivorous fish, omnivorous fish, filter-feeding fish and other species. These fish with different feeding habits reflect the adaptive evolution of fish in the long-term natural survival process. In a fish population, such as largemouth bass, there will be a transition state inside it. That is, some individuals are more carnivorous, and some individuals are omnivorous. Under the living conditions of the natural environment, when meat bait is scarce, individuals that tend to be omnivorous are more likely to survive. This intraspecific heterogeneity is caused by the environment and controlled by genetic genes, and is an inevitable result of genetic evolution. In the breeding process, targeted selection of groups with the same heterogeneous individuals within the same species is of great significance for variety selection.

[0003] As for the largemouth bass, it is a high-quality edible fish with a high meat yield, good taste, delicious flavor, and no intramuscular spines. It is native to the Americas and has been introduced to various parts of the world for breeding due to its excellent quality. The largemouth bass is a wide-temperature, carnivorous fish that can be fed with artificial feed and domesticated. It can be farmed in freshwater or in delta areas with a certain salinity. After nearly four decades of development, especially in recent years, the scale of breeding has continued to expand, with an annual output of more than 700,000 tons, known as the fifth largest fish in my country. The rapid development of the largemouth bass in my country has benefited from the success of artificial breeding in recent years and the widespread use of artificial synthetic feed in the breeding and cultivation of fry. The largemouth bass is an omnivorous fish that mainly feeds on meat. The starter bait of the water splash fish fry is rotifers and nauplii, and Artemia larvae are fed under artificial feed. Juvenile fish mainly feed on cladocerans, and artificial feed conditions are fed with live or fresh cladocerans. Juvenile fish mainly feed on large zooplankton such as copepods, and artificial feed is micro-particle feed. .

[0004] At present, under artificial breeding conditions, the survival rate of largemouth bass fry is about 30%-40%, which is mainly caused by cannibalism. The main reason for the cannibalism of largemouth bass is that largemouth bass are predatory, have a large food intake, and have carnivorous characteristics. Under normal circumstances, young fish about 3 cm long can eat small fish. Young fish can eat small fish that are 60%-70% of their own body length, and the food intake can reach 50% of their own body weight. If they are not fed enough, eat unevenly or the food is not palatable, picky or hungry individuals will attack their own kind, and cannibalism is likely to occur. Mutual cannibalism between largemouth bass will soon cause large differences between individuals, and this difference exacerbates the phenomenon of cannibalism.

[0005] In the actual seedling raising process, except for the starter feed, the feed used in other stages is mainly artificial synthetic feed. In the initial synthetic feed domestication process, some individuals are more likely to choose synthetic feed and achieve better growth, while some individuals have a low response to synthetic feed and will not eat synthetic feed, resulting in no food to eat, and will quickly become thin or even die. Of course, there are also fry that have a low response to synthetic feed but a strong response to meat. Such fry will cannibalize other individuals, and those thin individuals will be eaten by such fry.

[0006] In general, under large-scale artificial breeding conditions, even if the fry are of the same size and are fed all day, cannibalism may occur under conditions of abundant bait. Largemouth bass that cannibalize other fry are individuals that are relatively stubborn in their preference for meat. How to eliminate individuals that are relatively stubborn in their preference for meat in a largemouth bass group and select more omnivorous individuals has become an important topic in largemouth bass breeding technology. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a strain selection method for omnivorous largemouth black bass in view of the deficiencies in the prior art, which can screen out stubborn carnivorous individuals in the largemouth black bass population and select more omnivorous individuals, thereby improving the survival rate, saving breeding costs, being more suitable for feed breeding, and also reducing breeding risks.

[0008] The method for selecting a strain of omnivorous largemouth bass of the present invention comprises:

[0009] The acclimation environment construction step is used to construct a fry breeding pond with the function of timely luring largemouth black bass fry to feed based on light luring combined with water temperature regulation;

[0010] a fry breeding step, for placing newly hatched largemouth black bass fry in the fry breeding pond, and using different types of bait to adequately feed the newly hatched largemouth black bass fry through a stage feeding method, so as to breed the newly hatched largemouth black bass fry to selected individuals of a set length;

[0011] The reverse partial fry selection step is used to semi-starve the selected individuals so that the carnivorous individuals can eat other selected individuals; the carnivorous individuals can be selected from them;

[0012] The breeding and reproduction step is used to feed the unselected individuals with sufficient bait using synthetic feed until all the selected individuals grow into adult fish; the adult fish are used as parents for breeding to obtain a new generation of largemouth black bass fry;

[0013] The target fry acquisition step is used to cultivate the new generation of largemouth black bass fry through the acclimation environment construction step, the fry breeding step, the reverse biased fry selection step, and the breeding and reproduction step, and this is repeated at least twice; the new generation of largemouth black bass fry obtained in the last time is used as the target fry.

[0014] The method for constructing the fry breeding pond with the timed luring function is as follows:

[0015] The first step is to build a light-proof fish fry breeding pond indoors, and install a largemouth bass attracting light on the water surface of the fish fry breeding pond;

[0016] The second step is to set an automatic temperature control system in the fry breeding pond;

[0017] The third step is to set a day as a feeding period and a rest period, and set a plurality of feeding cycles with fixed intervals in the feeding period; if the current time is within the feeding period, the largemouth black bass attracting light is turned on, otherwise the largemouth black bass attracting light is turned off; if the current time is within the feeding period, the automatic temperature control system is turned on; if the current time is within the rest period, the automatic temperature control system is turned off.

[0018] After the feeding cycle ends, the largemouth bass attracting light continues to light up for at least half an hour before being turned off.

[0019] The largemouth bass attracting light is a light that emits yellow light.

[0020] The stage feeding method is:

[0021] The bait type is changed every week; when the newly hatched largemouth black bass fry are placed in the fry breeding pond, they are fed with Artemia larvae in the first week; they are fed with synthetic feed with the smallest particle size in the second week; and in each subsequent week, synthetic feed with a particle size one label larger than that of the synthetic feed in the previous week is fed until the largemouth black bass fry grow to 2.5-4 cm.

[0022] The feeding cycle is 2-4 hours.

[0023] When the largemouth black bass fry are cultured to the second week, the water level of the fry culture pond is deepened by at least one meter; and the water quality is monitored at least twice a day to ensure that the dissolved oxygen in the water in the fry culture pond is above 4 mg / L, has no odor, and is clear and not yellow; if the water quality does not meet the requirements, replace the water in the fry culture pond to ensure that the water quality meets the standards.

[0024] The semi-starvation feeding method is to feed the synthetic feed once in the morning every day, and the feeding amount is the normal feeding amount; and feed the synthetic feed once in the afternoon, and the feeding amount is half of the normal feeding amount.

[0025] The method for screening the omnivorous candidate individuals is as follows: after the candidate individuals are semi-starved and fed, the candidate individuals are scooped up from the water by a net with a set mesh size before being fed the next morning; and the candidate individuals with abnormally swollen abdomens on the net are selected as the omnivorous candidate individuals; and this is repeated for several days until there are no candidate individuals with abnormally swollen abdomens on the net.

[0026] Beneficial Effects

[0027] The advantages of the present invention are:

[0028] 1. Through light induction and water temperature regulation, the largemouth black bass fry in the fry breeding pond are induced to feed, so as to domesticate the feeding rules of the largemouth black bass fry. At the same time, it can also effectively reduce the waste of bait, ensure the uniformity of the fry's feeding and the rest time of the fry, and lay the foundation for the later breeding and selection.

[0029] 2. Combining the semi-starvation feeding method with the selection of largemouth black bass fry in the fry breeding pond can effectively screen out the omnivorous individuals, thereby realizing the classification of the feeding habits of largemouth black bass fry. In addition, in the selection process, the smaller and weaker individuals will be eliminated, which will improve the overall quality of the group and achieve the improvement of the fry. In addition, feeding these individuals after feeding habits classification separately can reduce the phenomenon of cannibalism and improve the survival rate. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the embodiments, but it does not constitute any limitation to the present invention. Any limited number of modifications made by anyone within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0031] The invention discloses a strain selection method for omnivorous largemouth sea bass, comprising a domestication environment construction step, a fry culture step, a reverse fry selection step, a breeding step and a target fry acquisition step.

[0032] Among them, the domestication environment construction step is used to construct a fry breeding pond with the function of regularly luring largemouth black bass fry to feed based on light luring combined with water temperature regulation. By controlling the lighting time and the pool water temperature, the feeding rules of largemouth black bass fry are domesticated. The advantage of this is that it can effectively reduce the phenomenon of bait waste.

[0033] The specific method for constructing a fry breeding pond with a timed lure function is:

[0034] The first step is to build a light-proof fish fry breeding pond indoors, and install yellow largemouth bass attracting lights around the water surface of the fish fry breeding pond, using the phototaxis of largemouth bass when feeding to attract largemouth bass to feed. And according to the characteristics of largemouth bass, yellow light can increase the appetite of largemouth bass compared to other lights.

[0035] The second step is to set up an automatic temperature control system in the fry breeding pond to control the water temperature in the fry breeding pond.

[0036] Step 3: Set a day as a feeding period and a rest period, and set multiple fixed-interval feeding cycles during the feeding period. Specifically, the rest period can be set to about eight hours from late night (such as 22:00) to early morning, and the rest of the time period is the feeding period. During the feeding period, every three hours is a feeding cycle.

[0037] If the current time is within the feeding cycle, feed the bait. Feeding is carried out in a small amount per unit time and evenly. Turn on the largemouth black bass attractor light while feeding; and turn off the largemouth black bass attractor light half an hour after the feeding is finished to ensure that the bait in the fry breeding pond can be eaten by the largemouth black bass fry as much as possible. Under the light conditions, the largemouth black bass fry in the pond are gathered and domesticated so that the largemouth black bass fry form a light feeding response. Turning off the light after feeding is to reduce the activity and extra feeding of the largemouth black bass fry, to ensure that the fry are fed evenly, and to lay the foundation for later breeding and selection.

[0038] If the current time is in the feeding period, the automatic temperature control system is turned on to make the water temperature suitable for the activities of largemouth black bass fry. If the current time is in the rest period, the automatic temperature control system is turned off to lower the water temperature to the natural environment state, reduce the activities of largemouth black bass fry, make them get enough rest, play a role in increasing the immunity of the fry and saving energy.

[0039] The fry breeding step is used to place the newly hatched largemouth black bass fry in the fry breeding pond. The breeding density is about 10,000 per square meter of the fry breeding pond. When feeding, the type of bait is changed every week. For example, in the first week, feed Artemia larvae; in the second week, feed the synthetic feed with the smallest particle size; and in each subsequent week, feed the synthetic feed with a particle size one number larger than the particle size of the synthetic feed in the previous week until the largemouth black bass fry grows to about 3 cm.

[0040] During this stage of breeding, sufficient bait must be fed each time to enable the largemouth black bass fry to grow quickly. In addition, during this stage of breeding, some individuals with strong synthetic feed intake have fully grown and become larger, while individuals with weak feeding ability grow slowly and are prone to become weak and black, and gradually die, thus achieving natural selection and survival of the fittest.

[0041] As the fry grow, there is no need to separate the fry into ponds. However, when the largemouth bass fry are cultured for the second week, the water level of the fry culture pond should be deepened by at least one meter to allow the largemouth bass fry to have more room to move. In addition, during the fry culture period, the water quality should be monitored twice a day to ensure that the dissolved oxygen in the fry culture pond is above 4 mg / L, there is no odor, and the water color is clear and not yellow. If the water quality does not meet the requirements, replace the water in the fry culture pond to ensure that the water quality meets the standards.

[0042] When the largemouth black bass fry is about 3 cm long, it can be selected through the reverse partial fry selection step to select the carnivorous individuals to be selected. The specific selection method is combined with the semi-starvation feeding method. Specifically,

[0043] When it is necessary to screen the candidates, feed the synthetic feed once in the morning of the same day, and the feeding amount is the normal feeding amount. Feed the synthetic feed once in the afternoon, and the feeding amount is half of the normal feeding amount. On the next morning, when the candidates have not been fed yet, use a net with a mesh that allows largemouth black bass fry in a semi-starved or hungry state to pass vertically to pick up the candidates from the water. Most of the largemouth black bass fry in a semi-starved or hungry state can fall back into the water through the net. However, there will be a part of the largemouth black bass fry that cannot fall into the water through the net. Moreover, most of these largemouth black bass fry have abnormally swollen abdomens.

[0044] The main reason for the abnormally swollen abdomen of these largemouth black bass fry is that in an environment with sufficient bait, largemouth black bass fry can normally eat sufficient bait, and most largemouth black bass fry will not be aggressive towards other individuals of the same species. However, when the environment lacks bait, some carnivorous largemouth black bass fry will be increasingly stimulated to be carnivorous, resulting in cannibalism, and some smaller and weaker fry will be eaten by these omnivorous fry. The abdomen of largemouth black bass fry that have eaten other fry is obviously abnormally swollen, and these largemouth black bass fry will find it difficult to fall back into the water through the net.

[0045] Therefore, we only need to select the individuals with abnormally swollen abdomens on the net as the stubborn carnivorous individuals.

[0046] After the selection is completed, the fry are still fed once a day in the morning, which is the normal feeding amount; and once in the afternoon, which is half of the normal feeding amount, so that the fry are in a semi-starved state. Wait until the next morning to pull the net to screen the fry again. After screening the fry in this way for several days, it is found that the number of largemouth black bass fry with abnormally swollen abdomens is getting smaller and smaller, and when there are no largemouth black bass fry with abnormally swollen abdomens, the screening of fry can be stopped and normal feeding can be switched. At this time, we will get two types of largemouth black bass fry: one is omnivorous largemouth black bass fry; the other is carnivorous stubborn or likely to become carnivorous stubborn largemouth black bass fry.

[0047] Since meat feed is relatively expensive, the largemouth black bass fry that are stubborn in carnivorousness or may become stubborn in carnivorousness can be eliminated. As for the selected individuals that have not been screened out, they are fed with sufficient bait using synthetic feed until all the selected individuals grow into adult fish.

[0048] About feeding density. When the selected largemouth bass fry are first fed, the feeding density is one to two thousand per square meter of the breeding pond. However, in the subsequent breeding process, the breeding density needs to be adjusted accordingly according to the size of the fry to ensure the activity space of the largemouth bass. For example, the breeding density needs to be reduced once the fry grows to 10 cm.

[0049] After obtaining the adult fish, the adult fish are used as parents for breeding to obtain a new generation of largemouth black bass fry. Since there are many adult fish finally bred, we can select relatively strong and healthy adult fish from these adult fish as parents. The number of selected fish can be 120 male and female fish, which are placed in the spawning pond for breeding and spawning. Then they are collected in the fish nest for artificial hatching.

[0050] However, after one screening, a group with stable traits cannot be obtained. Therefore, it is necessary to continue to cultivate and breed largemouth black bass fry for many times through the steps of building an acclimation environment, raising fry, selecting reverse-biased fry, and breeding. The number of breeding and breeding can be 4 times in total. That is, the fourth generation of largemouth black bass fry obtained in the fourth time is used as the target fry. The feeding stability of these fry will be very obvious, which is more conducive to breeding.

[0051] Experiments have shown that through this kind of selection, the amount of feed consumed by each generation is significantly increased, and the types of feed consumed are stable, with fewer cases of picky eating or fighting each other. The benefit brought about by this is that the survival rate of each generation cultivated to 10 cm is increased by nearly 8%, achieving a significant improvement effect.

[0052] The above is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A method for selecting a strain of omnivorous largemouth bass, characterized in that: include, The acclimation environment construction step is used to construct a fry breeding pond with the function of timely luring largemouth black bass fry to feed based on light luring combined with water temperature regulation; a fry breeding step, for placing newly hatched largemouth black bass fry in the fry breeding pond, and using different types of bait to adequately feed the newly hatched largemouth black bass fry through a stage feeding method, so as to breed the newly hatched largemouth black bass fry to selected individuals of a set length; The reverse partial fry selection step is used to semi-starve the selected individuals so as to make the selected individuals with stubborn carnivorous nature eat other selected individuals; Screening out the carnivorous and stubborn individuals to be selected; The breeding and reproduction step is used to feed the unselected individuals with sufficient bait using synthetic feed until all the selected individuals grow into adult fish; the adult fish are used as parents for breeding to obtain a new generation of largemouth black bass fry; The target fry acquisition step is used to cultivate the new generation of largemouth black bass fry by means of the acclimation environment construction step, the fry cultivation step, the reverse biased fry selection step, and the cultivation and breeding step, and this is repeated two to four times; the new generation of largemouth black bass fry obtained in the last step is used as the target fry; The method for constructing the fry breeding pond is as follows: The first step is to build a light-proof fish fry breeding pond indoors, and install a largemouth bass attracting light on the water surface of the fish fry breeding pond; The second step is to set an automatic temperature control system in the fry breeding pond; Step 3: set a day as a feeding period and a rest period, and set a plurality of feeding cycles with fixed intervals in the feeding period; if the current time is within the feeding period, the largemouth bass attracting light is turned on, otherwise the largemouth bass attracting light is turned off; if the current time is within the feeding period, the automatic temperature control system is turned on; if the current time is within the rest period, the automatic temperature control system is turned off; The stage feeding method is: The feed type is changed every week; when the newly hatched largemouth black bass fry are placed in the fry breeding pond for the first week, they are fed with Artemia larvae; in the second week, they are fed with synthetic feed with the smallest particle size; and in each subsequent week, synthetic feed with a particle size one number larger than that of the synthetic feed in the previous week is fed until the largemouth black bass fry grow to 2.5-4 cm; The semi-starvation feeding method is to feed the synthetic feed once in the morning, and the feeding amount is the normal feeding amount; and feed the synthetic feed once in the afternoon, and the feeding amount is half of the normal feeding amount; The method for screening the carnivorous and stubborn individuals to be selected is as follows: after the individuals to be selected are semi-starved and fed, the individuals to be selected are scooped up from the water by a net with a set mesh size before being fed the next morning; and the individuals to be selected with abnormally swollen abdomen on the net that cannot pass through the net and fall into the water are selected as the carnivorous and stubborn individuals to be selected; and this process is repeated for several days until there are no individuals to be selected with abnormally swollen abdomen on the net.

2. The method for selecting a strain of omnivorous largemouth bass according to claim 1, characterized in that: After the feeding cycle ends, the largemouth bass attracting light continues to light for half an hour before being turned off.

3. The method for selecting a strain of omnivorous largemouth bass according to claim 2, characterized in that: The largemouth bass attracting light is a light that emits yellow light.

4. The method for selecting a strain of omnivorous largemouth bass according to claim 1, characterized in that: The feeding cycle is 2-4 hours.

5. The method for selecting a strain of omnivorous largemouth bass according to claim 1, characterized in that: When the largemouth black bass fry are cultured to the second week, the water level of the fry culture pond is deepened by at least one meter; and the water quality is monitored at least twice a day to ensure that the dissolved oxygen in the water in the fry culture pond is above 4 mg / L, has no odor, and is clear and not yellow; if the water quality does not meet the requirements, replace the water in the fry culture pond to ensure that the water quality meets the standards.