JP5121577B2 - Production method of fry of recurring fish - Google Patents

Description

  The present invention relates to a method for producing a fry of a recurring fish that produces a fry before release through a hatching period, a fish breeding period, and a breeding period after egg collection and fertilization during the propagation of the reversion fish such as salmon and masashi.

  In cultivated fisheries such as salmon, masashi, etc., the fish that have returned have been captured and, if necessary, farmed until maturity, then egg collection and fertilization were performed, and the fertilized eggs were raised in the hatching room (or incubator) The eggs just before hatching are transferred to fish farms and the hatched larvae are raised there. The juveniles that have started swimming are moved to the breeding grounds, where they are fully grown and then released into the river at an appropriate time.

  For example, in the case of salmon returning to the coast of Hokkaido, the autumn salmon is captured and collected in the first half of August and September, the middle of October, the second half of November and December, and the Fisheries Agency Salmon and Resource Management Center. The larvae are produced in such a way that fully grown fry are released into the river between April and July.

  On the other hand, the water temperature at which the survival rate of salmon fry is high is confirmed to be 9.5 to 12.5 ° C. in the past research. It has been found that the “concentrated discharge method” that discharges from the beginning of June to the beginning of July when the water temperature is in this range can expect a more stable return. The salmon return time is determined by the hatching time rather than the release time, so even in the “concentrated discharge method”, the return time is not concentrated and there is no worry of adjusting the landing balance by the concentration of the return.

In order to adopt this `` concentrated release method '', it is required to release juveniles produced from eggs captured and collected at different times of the first, middle and late periods in the same growth state at the same time, In the prior art described in Patent Document 1 below, for the production of fry from eggs captured and collected in the first or middle period, the temperature of the production water is controlled to be low, during the hatching period, the fish breeding period, and the breeding period. Suppression of the growth of eggs, larvae or fry is carried out according to the time of release. Patent Document 1 listed below discloses that production water is given a temperature change similar to a water temperature change of a natural river by performing a constant water temperature adjustment on the raw water collected from the natural river. .
JP 2001-238560 A

  Natural salmon, masu and other recurring fish are spawned and fertilized in a suitable place, such as gravel, where the temperature changes relatively little, and then grows from the hatched larvae to fry. It will grow further down the river. In the meantime, even when under a gravel with relatively little temperature change, the water temperature is different between daytime and after sunset, so the eggs grow from eggs to fry while undergoing a daily change in temperature. In other words, natural salmon, masashi, and other regressing fish grow by grasping the elapsed time while working the biological clock that is originally possessed by living organisms by receiving temperature changes in a daily cycle as time information. Then, it can be considered that a regression cycle that does not mistake the timeliness can be realized by growing after grasping this elapsed time.

  In contrast, in the growth of recurring fish, the egg or fish is given an artificial environment during the period from egg collection and fertilization to the release period after the hatching period, the fish breeding period, and the breeding period. Growth from eggs to larvae and fry will be performed in an environment that does not receive time information. As a result, so-called greenhouse-grown fry is produced, and there is a problem that the adaptability to the natural environment is lowered and the survival rate and the regression rate are lowered.

  In addition, it has been considered to increase the absolute amount of fry without increasing efficient production, and the essential items necessary for the growth of the fish have been neglected. Therefore, the survival rate of juveniles after release will be low, and juveniles that will not lead to return will be produced, so that productivity will be increased efficiently, such as waste of production costs and excessive costs per fish. There was a problem that could not be.

  In the prior art described in Patent Document 1 described above, it has been proposed to change the temperature of the production water along a natural temperature fluctuation curve, but time information for giving a temperature change in a daily cycle to an egg or fry. It is not considered as new growth control or promotion control using this.

  The present invention has been proposed for such a situation, and in the production process of fry during the hatching period, fish breeding period, and breeding period, the survival rate of the fry is given by providing time information necessary for the growth of the fish. , Enabling the growth of recurring fish, which can increase the reversion rate and improve the productivity efficiently, and control the time information given during fry production using the biological clock that the recurring fish originally has Thus, it is an object of the present invention that the growth of fry can be controlled.

In order to achieve such an object, the present invention is a method for producing a fry of a recurring fish that produces fry before being released into a river after hatching, fish raising, and rearing after egg collection and fertilization. The production water used in some or all of the seasons and the breeding season is given a temperature change with a period equivalent to one day that can be set arbitrarily, and the period of the temperature change given to the production water is set shorter than the day It is characterized by promoting the growth of fry .

  In addition, it is a method for producing fry of recurring fish that produces fry before release into the river after hatching, fish raising, and breeding after egg collection and fertilization, and is used in some or all of the hatching, fish raising, and breeding The production water to be given is given a temperature change with a period corresponding to one day that can be arbitrarily set, and the period of the temperature change given to the production water is set longer than the day, thereby suppressing the growth of fry It is characterized by.

  The present invention having such a feature is used for the production of artificial fish, such as salmon, masashi, etc., for the production of artificial fry before release into the river after hatching, fish breeding and breeding after egg collection and fertilization. , Because it gives a temperature change with a period corresponding to one day that can be set arbitrarily to the production water used in part or all of the fish breeding season and the breeding season, this time change gives time information to the growing fish The fish can grow by grasping the elapsed time based on the given time information while working the biological clock that the organism originally has. In other words, because the production of artificial fry can be provided with information similar to that of natural fry, the environment suitable for fish growth is incorporated into the artificial environment that excludes external enemy factors and released. It becomes possible to carry out fry production that obtains a high survival rate and a high return rate later.

  Compared with growth control (suppression or promotion) only by raising or lowering the average temperature of production water by setting the period of temperature change given to production water as appropriate, it is based on biological reactions using the biological clock that fish originally has Since growth control can be performed, growth can be suppressed or promoted without giving an unreasonable environment to the fish.

  When suppressing growth, the period of the temperature change given to the production water is set longer for one day (24 hours). This will make the fish grow slower than usual, feeling the day longer than it actually is. Conversely, when promoting growth, the period of temperature change given to the production water is set shorter than one day. This allows the fish to grow faster than normal, making the day feel shorter than it actually is.

  Create an environment close to the natural production water temperature change by changing the temperature change given to the production water to an amplitude obtained by reducing the daily fluctuation amplitude of the temperature change of the river to be discharged or the surrounding outside air by a fixed ratio. And can grow close to a damn natural fish.

  By matching the temperature of the production water in the breeding season with the temperature of the river to be discharged before the release, it is possible to prevent a sudden temperature step (temperature shock) from being given to the fish during the release. A high survival rate and a high regression rate can be obtained also by this.

  Moreover, the temperature change given to production water can also be set based on the temperature change data of the production water performed at the time of past fry production. According to this, by keeping the correlation between the temperature change data of the production water and the regression rate statistically, and using the data when the past regression rate was high, giving the optimum temperature change to the production water, It is possible to achieve a high return rate that is not affected by weather changes such as global warming.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing a system configuration for executing a fry production method for recurring fish according to an embodiment of the present invention. This system consists of a hatchery pond 1 containing eggs and fry of return fish such as salmon salmon, and heating / cooling means 2 for heating or cooling raw water from a water supply source (not shown) such as a river or sea. , The cold water tank 3 for storing the cooled raw water, the hot water tank 4 for storing the heated raw water, the low-temperature water from the cold water tank 3 and the high-temperature water from the hot water tank 4 while switching and supplying the produced water And a three-way valve 5 to be generated.

  The raw water from the water supply source is supplied to the cold water tank 3 and the hot water tank 4 through the water supply pipe 10 and the water supply pipe 11 branched from the water supply pipe 10, respectively, and from the cold water tank 3 to the hot water tank 4 through the water supply pipes 12 and 13. Then, it is guided to the three-way valve 5 and supplied to the hatching pond 1 through the water supply line 14 via the three-way valve 5. The water supply pipes 10 and 11 are respectively provided with water supply pumps 20 and 21 and flow rate adjusting valves 22 and 23 as necessary.

  Hatching and breeding pond 1 is, for example, a hatching tank (or hatcher) used in the hatching period, a fish pond used in the fish farming period, a breeding pond used in the breeding period, a combined pond or other water tank in the fish farming stage and the breeding stage, or Including natural ponds, etc., if multiple hatchery tanks or fish ponds are provided in the same place and are transferred from the hatching tank to the fish pond or combined pond when the hatching is completed, for example, when the hatching is completed, This includes the case where the fish pond is moved to the breeding pond according to the growth stage. That is, it is a collective term for tanks (or ponds) used in part or all of the hatching period, fish farming period, and breeding period.

  And the water supplied to the hatching breeding pond 1 via the water supply line 14 is the production water used in part or all of the hatching period, the fish breeding period, and the breeding period. This product water is stored in the hatchery pond 1 and comes into direct contact with eggs and fry. The fry referred to here includes all fry from hatched larvae to release.

  The heating / cooling means 2 is, for example, a heat pump, a heat exchanging unit 2A (evaporator) provided in the middle of the water supply line 10, a heat exchanging unit 2B (condenser) provided in the middle of the water supply line 11, The compression / expansion part 2C provided over both of them is provided. The heat exchange unit 2A (evaporator) vaporizes the heat exchange gas supplied from the compression / expansion unit 2C to cool the raw water, and the heat exchange unit 2B (condenser) includes the compression / expansion unit 2C. The heat exchange gas supplied from is condensed to heat the raw water.

  In the hatchery breeding pond 1, a drain outlet 1A is opened so that eggs and fry do not flow out directly, and a drain pipe 15 is connected to the drain outlet 1A, and the tip of the drain pipe 15 communicates with the outside of the tank. The product water in the tank is drained from the drain port 1A so that all the product water is replaced.

  Below, the fry production method of the return fish which concerns on embodiment of this invention with the function of the control means 6 is demonstrated. As shown in FIG. 1, the control means 6 receives information (air temperature, water temperature) detected by a temperature sensor 60 that detects the temperature of ambient outside air or river water, switches the three-way valve 5, and heats / cools means 2. And the operations of the feed water pumps 20 and 21 are controlled. In order to give a periodic temperature change to the product water supplied to the hatchery pond 1, the three-way valve 5 is periodically switched so that the hot water and the cold water are alternately joined to the product water to periodically change the temperature. Is granted.

  Based on the detection information of the temperature sensor 60, the control means 6 can generate a production water fluctuation pattern from past or present outside air temperature or river water temperature fluctuation data. Further, the fluctuation pattern of the production water to be controlled this time may be generated from the past fluctuation pattern data of the production water that is correlated with the regression rate data.

  When generating the fluctuation pattern of production water from past or present outside air temperature or river water temperature fluctuation data, for example, the amplitude obtained by reducing the daily fluctuation amplitude of the temperature change of the outdoor air in the river to be discharged or its surroundings by a certain ratio is reduced. It has a temperature change corresponding to the daily average of the temperature change of the river or its surrounding outside air that discharges the average temperature of one cycle. This makes it possible to bring the produced water close to the environment in which natural fry grows.

  When generating the fluctuation pattern of the production water to be controlled this time from the fluctuation pattern data of the past production water that has been correlated with the regression rate data, for example, based on the temperature change data of the production water performed during the past fry production Thus, it is possible to set a variation pattern and generate computer-simulated data so as to obtain a high regression rate.

  On the other hand, by adjusting the degree of heating or cooling of the heating / cooling means 2, the base temperature of the product water supplied to the hatchery pond 1 can be adjusted. The base temperature of the production water is controlled in accordance with, for example, a gradual change in the outside air temperature that changes according to the season, thereby forming a situation suitable for the growth of fry in consideration of the river water temperature at the time of discharge. Finally, by matching the temperature of the produced water with the river water temperature at the discharge destination immediately before the discharge, the fry can be prevented from being shocked by a large temperature change before and after the discharge.

In order to give the production water a temperature change with a period corresponding to one day, a temperature change period and a temperature change amplitude are set. Specifically, by switching the three-way valve 5 at a set cycle, the case where hot water is supplied to the water supply line 14 and the case where cold water is supplied to the water supply line 14 are periodically switched. As a result, a periodic temperature change as shown in FIG. 2 is given to the produced water. One cycle can be set to one day (T ₀ = 24 hours) (FIG. (A)), or can be set longer than one day (T ₀ <T ₁ : (b)). It can also be set short for one day (T ₀ > T ₂ : (c) in the figure).

  When one cycle is set longer than one day, the fry feels longer than the actual one based on the time information received from the temperature change of the production water, thereby delaying the growth rate. In addition, when one cycle is set shorter than one day, the fry feels that the day is shorter than the actual time according to the time information received from the temperature change of the production water, thereby increasing the growth rate.

  FIG. 3 is an explanatory view showing an example of temperature control of production water. The base temperature of the production water until it is released after hatching, fish raising, and breeding is controlled as shown in Fig. (A). On the other hand, the periodic temperature change is shown in Fig. (B). Append. As shown in the figure (a), the base temperature of the production water is controlled to coincide with the river water temperature that changes along with the change in the outside air temperature at the early hatching period after egg collection and fertilization. It is controlled so that it becomes higher than the river water temperature and changes gently along the average temperature change of the river water temperature, and it is controlled so as to coincide with the river water temperature immediately before the discharge. And as shown in the figure (b), the cycle temperature change of production water is fluctuate-controlled so that the amplitude of the river water temperature which fluctuates by the daily cycle T is reduced by a predetermined ratio.

  According to this, a seasonal temperature change is given to the production water for artificial fry breeding, and a cyclical temperature change is given to the natural fry during the growth process. The received time information can be given to production water in artificial fry breeding. As a result, the biological clock originally possessed by the organism is stimulated by the given time information, and the artificially nurtured fry can be encouraged to grow in the same natural environment as the natural fry. It is possible to improve the growth rate after discharge or improve the return rate thereafter.

  4-6 is explanatory drawing which showed other embodiment of this invention. Portions common to the above-described embodiment are denoted by the same reference numerals, and redundant description is omitted. The example shown in FIG.4 and FIG.5 supplies the production water cooled with the heating / cooling means 2 to one hatching breeding pond 1, and makes it the water tank for suppression which suppresses the growth of fry with low temperature water, The production water heated by the cooling means 2 is supplied to the other hatching breeding pond 1 to form a promotion water tank that promotes the growth of fry with high-temperature water. In the example shown in FIG. 4, the periodic temperature change of the production water is performed by the operation control means 61 of the heating / cooling means 2, for example, the rotational speed control by an inverter, and in the example shown in FIG. This is done by changing the amount of water supplied by controlling the valves 30 and 31.

  In the example shown in FIGS. 4 and 5, when the average temperature of the production water is lowered or raised to suppress or promote the growth of fry, the production water has a period equivalent to one day close to the natural environment. Therefore, the time information necessary for the growth of the fish can be given even in the production of fry with controlled growth, and the survival rate and the regression rate of the fry can be improved.

  FIG. 6 shows a configuration example in which a temperature change with a period corresponding to one day is given to the produced water with a simpler system configuration. Here, using raw water with different temperatures, for example, groundwater and river water, supplying groundwater as cold water and river water as hot water while switching them periodically with the three-way valve 5, periodic temperature changes can be achieved. It is given. According to this, since a necessary temperature change can be given without using a heat source in particular, the system can be constructed at low cost and the running cost can be reduced.

  As described above, according to the present invention, in the production process of fry during the hatching period, the fish breeding period, and the breeding period, the time information necessary for the growth of the fish is given, so that the survival rate and the regression rate of the fry can be improved and efficient. This makes it possible to grow recurrent fish that can improve productivity. Moreover, the growth of the fry can be effectively controlled by controlling the time information given at the time of the fry production using the biological clock originally possessed by the recurring fish.

It is explanatory drawing which showed the system configuration | structure for performing the fry production method of the return fish which concerns on embodiment of this invention. It is explanatory drawing which shows the temperature change period setting in embodiment of this invention. It is explanatory drawing which showed the temperature control example of production water. It is explanatory drawing which showed the system configuration | structure for performing the fry production method of the return fish which concerns on other embodiment of this invention. It is explanatory drawing which showed the system configuration | structure for performing the fry production method of the return fish which concerns on other embodiment of this invention. It is explanatory drawing which showed the system configuration | structure for performing the fry production method of the return fish which concerns on other embodiment of this invention.

Explanation of symbols

1: hatching pond, 2: heating / cooling means, 3: cold water tank, 4: hot water tank, 5: three-way valve,
6: control means, 60: temperature sensor, 10-14: water supply pipeline

Claims (4)

A method for producing fry of recurring fish that produces fry before release into a river after hatching, fish raising and breeding after egg collection and fertilization,
A temperature change with a period corresponding to one day that can be arbitrarily set is given to the production water used in part or all of the hatching period, fish cultivation period, and breeding period ,
A fry production method for recurring fish, characterized in that the growth of fry is promoted by setting the cycle of temperature change given to the production water to be shorter than one day . A method for producing fry of recurring fish that produces fry before release into a river after hatching, fish raising and breeding after egg collection and fertilization,
A temperature change with a period corresponding to one day that can be arbitrarily set is given to the production water used in part or all of the hatching period, fish cultivation period, and breeding period,
A method for producing fry of recurring fish, characterized in that growth of fry is suppressed by setting a period of temperature change given to the production water to be longer than that of one day . 2. The fry of the recurrent fish according to claim 1, wherein the temperature change given to the production water has an amplitude obtained by reducing the daily fluctuation amplitude of the temperature change of the river to be discharged or the ambient air in the vicinity thereof by a certain ratio. Production method. The temperature change given to the production water is controlled according to the daily average of the temperature change of the river that discharges the average temperature of one cycle or the surrounding air. Described fry production method for recurring fish.

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