JP4262102B2 - Anemonefish growth method and effect evaluation test method - Google Patents

Description

  The present invention relates to a method for growing saltwater fish and an effect evaluation test method using saltwater fish grown by the method. More specifically, the present invention relates to a method for growing clownfish and an effect evaluation test method using clownfish grown by the method.

  Anemone fish are also popular as ornamental fish, and most anemone fish currently in circulation have been caught in natural waters, but some anemone fish are also breeding. In the breeding of saltwater fish, rotifers are exclusively used as feed for hatchling larvae, and Patent Document 1 discloses a method for preserving rotifers with eggs in order to stably supply rotifers. In the breeding of anemone fish, rotifers are used as the initial food, as with other saltwater fish. On the other hand, as shown in Patent Document 2, an initial mixed feed replacing rotifer has also been developed.

  By the way, freshwater fish are exclusively used in the aquatic organism impact assessment test. The impact assessment test gives the test target factors to the environmental water of aquatic organisms, for example, contains test target substances such as toxic substances in the environmental water, uses polluted water as the environmental water, or vibrates the environmental water tank. The effect of the test target factors on the aquatic organisms is examined from the survival rate of the aquatic organisms, the growth rate, and the swimming disorder. Since aquatic organisms in the early life stage until about one month after hatching are highly sensitive to factors to be tested such as toxic substances, it is extremely important to conduct an impact assessment test in the early life stage. There are many types of freshwater fish that can be easily bred and reared, and an impact assessment test method has been established for the initial life stage. Further, as shown in Patent Document 3, the test method is simplified.

JP 2002-306015 A JP-A-9-308439 Japanese Patent Laid-Open No. 2003-83954

  Most anemone fish currently in circulation are collected in the natural sea area, and there is concern about the impact on the amount of resources as the distribution volume increases. For this reason, further increase in the artificial propagation of anemone fish is desired, and a technique for growing good-quality anemone fish and a technique for systematically securing an anemone fish and hatched larvae are desired.

  However, rotifers that are used as feed for hatchling larvae in the breeding of conventional saltwater fish must be maintained and cultured at all times, requiring a great deal of labor. Even when a rotifer is preserved in an egg by the technique of Patent Document 1, complicated work such as multiplication and nutrient enhancement is required before feeding the hatched larvae. In addition, since rotifers always take water into the body immediately after hatching, if the breeding water used for hatching or cultivating rotifers contains harmful substances such as harmful substances or pathogens, the rotifer contains the harmful substances. There is a risk that harmful substances will be taken into the seawater fish that are taken in and feed the rotifer. On the other hand, the mixed feed as shown in Patent Document 2, unlike the biological feed that swims in the water, floats on the water surface and gradually sinks and settles. The reality is that it has not been achieved. In addition, the spawning conditions of saltwater fish are hardly elucidated, and it is difficult to systematically secure eggs and hatched larvae.

  On the other hand, freshwater fish are used exclusively in the conventional aquatic organism impact assessment tests, but in recent years there has been a demand for impact assessment tests on marine fish, which are high-class species in the marine ecosystem and are important to industry. Yes. However, seawater hatched larvae are generally smaller than freshwater fish hatched larvae, and their survival rate is low even in clean environments, making it difficult to conduct an accurate impact assessment test and establishing appropriate test species. It has not been. In addition, when conducting an impact assessment test on saltwater fish, rotifers fed to hatchling larvae always take water into the body, so the rotifer itself is affected by the test target factors contained in the environmental water, and the test target It is difficult to accurately observe the influence of the test target factors on the fish itself. For this reason, it is very difficult to conduct an impact assessment test in the early life stage for marine fish.

  Then, an object of this invention is to provide the method of growing a good-quality anemone fish simply. Another object of the present invention is to provide a method for systematically securing anemonefish eggs and hatching larvae. A further object of the present invention is to provide a method for conducting an impact assessment test using anemone fish grown by the above method.

In order to achieve this object, the inventors of the present application have conducted research and breeding experiments, and as a result, found that anemonefish hatching larvae can grow only with Artemia without using a rotifer. Since the mouth of hatched larvae of saltwater fish is extremely small and weak in digestion ability, it was common knowledge to give rotifer for a while after hatching and then gradually switch to artemia or mixed feed. Focusing on the fact that larvae hatched larvae are relatively large among saltwater fishes, when Artemia was given to anemonefish hatched larvae, they found that they fed without problems and grew smoothly. In addition, as a result of the repeated experiments of anemonefish parent fish, the inventors of the present application placed anemonefish parent fish under environmental water with a water temperature of 25 ° C. to 28 ° C. and a light irradiation time of 12 hours to 18 hours per day. By setting the illuminance at the time of light irradiation in the environmental water to 1,000 lux to 100,000 lux and the illuminance at the time of not irradiating light to 10 lux or less, the anemonefish parent fish can be obtained in about two weeks. It came to know that egg-laying is repeated regularly with one frequency. The above water temperature and light irradiation conditions correspond to the breeding time of clownfish in the natural sea area, the water temperature of the breeding sea area, and the sunshine conditions.

The growth method of the anemone fish according to claim 1 is based on such knowledge, and the parent fish of the anemone fish is placed in an environmental water having a water temperature of 25 ° C. to 28 ° C. and a light irradiation time of 12 hours to 18 hours per day. The illuminance at the time of light irradiation in the environmental water is set to 1,000 lux to 100,000 lux, and the illuminance at the time of no light irradiation is set to 10 lux or less to obtain anemonefish hatching larvae. Instead of the rotifer, only the artemia before opening is administered to the hatched larvae.

Therefore, it is possible to stably obtain good-quality anemonefish eggs and hatched larvae by periodically laying eggs of the anemonefish. Moreover , anemone fish can be grown without using a rotifer as an initial feed. Artemia is widely distributed as dry and durable eggs, and is easy to obtain and store. It can be used as a feed by dipping in seawater in about 1 to 2 days. It is a biological feed that is extremely easy to prepare. Furthermore, since Artemia swims in water and becomes suspended, there is an advantage that anemonefish larvae that are clownfish are easy to feed, unlike mixed feeds that settle. Furthermore, since Artemia does not open for about a day after hatching, by using Artemia before opening, even if the seawater used for hatching contains harmful substances, it can be prevented that harmful substances are taken into Artemia. It can prevent harmful substances from being taken into the larvae of anemone fish that feed on artemia. Therefore, anemone fish can be easily grown and good-quality anemone fish can be propagated.

According to the second aspect of the present invention, there is provided a method for evaluating the effect of claim 2 , wherein an environmental water of anemone fish that has grown by administering only pre-opening artemia instead of a rotifer to a hatchling larvae of anemonefish contains a toxic substance, or The influence of the test object factor on the anemone fish is examined by giving the test object factor by making the environmental water polluted seawater or vibrating the environmental water tank. Further, the impact evaluation test method according to claim 3 is a method in which an environmental water of anemone fish grown by the method according to claim 1 contains a toxic substance, or the environmental water is contaminated seawater, or an environmental water tank is provided. The test subject factor is given by vibrating, and the influence of the test subject factor on the anemone fish is examined.

When artemia before opening is administered to hatchling larvae of clownfish, it is difficult to be affected by the test target factors contained in the environmental water. Therefore, it is possible to accurately observe the influence of the test target factor on the anemone fish itself, which is the test target fish, without considering the effect of the test target factor on the feed organism. Therefore, it is possible to easily carry out an impact assessment test for seawater fish including the initial development stage, which has been extremely difficult until now.

Therefore, according to the method for growing anemone fish according to claim 1, the water temperature corresponding to the breeding time of the anemonefish in the natural sea area, the water temperature of the breeding sea area and the sunshine condition, and a light irradiation time per day. Place anemone fish in the environmental water for 12 to 18 hours, set the illuminance at the time of light irradiation in the environmental water to 1,000 lux to 100,000 lux, and the illuminance when light is not irradiated is 10 lux or less Therefore, it is possible to stably obtain good-quality clownfish eggs and hatched larvae by periodically spawning the clownfish parent fish. And since only the artemia before opening is administered to the hatchling larvae of anemonefish instead of the rotifer, the anemonefish can be grown without using the rotifer as an initial food. Therefore, the troublesome work of constantly maintaining and cultivating rotifers is not necessary. In addition, since Artemia does not open for about one day after hatching, harmful substances can be prevented from being taken into the anemone fish through feed. Furthermore, since Artemia swims in water and becomes suspended, there is an advantage that anemonefish larvae that are clownfish are easy to feed, unlike mixed feeds that settle. Therefore, according to the present invention, clownfish can be easily grown and good-quality clownfish can be easily propagated.

Furthermore, according to the influence evaluation test method according to claim 2 or 3, since pre-opening artemia that is not easily affected by the test target factors contained in the environmental water is given to the hatched larvae of the anemonefish as feed, It is possible to accurately observe the influence of the test target factor on the fish, the anemone fish itself, without considering the effect on the feed organism. Therefore, it is possible to easily carry out an impact evaluation test for seawater fish including the initial development stage, which has been extremely difficult until now. In addition, stable supply of the test target fish is facilitated.

Hereinafter, an embodiment of an anemone fish growth method and an effect evaluation test method using the anemone fish of the present invention will be described in detail. In this anemonefish growth method, only the artemia before opening is administered to an anemonefish larvae instead of a rotifer.

  Artemia (brine shrimp) is widely distributed as a dry durable egg, is easy to obtain and store, and can be used as feed by hatching in seawater for about 1 to 2 days. Artemia durable eggs are hatched using, for example, natural seawater, and hatched artemia (brine shrimp larvae) is given to the anemonefish larvae in the early life stage. The initial life stage is, for example, a period from about one month after the hatching. The administration of Artemia is performed once a day, for example, and the feeding amount is preferably adjusted so that, for example, at least one individual Artemia that cannot be fed after 24 hours remains per ml of breeding water. When the anemone hatched larvae have been hatched for about one month, administer a mixed feed or seafood shredded product in addition to artemia, gradually reduce the amount of artemia feed, and blended feed or seafood shredded product Increase the amount of feeding and eventually switch to feeding only mixed feed or fish and shellfish.

  Therefore, anemone fish can be grown without using a rotifer as an initial feed, and the troublesome work of maintaining and cultivating a rotifer at all times becomes unnecessary. In addition, since Artemia does not open for about one day after hatching, harmful substances can be prevented from being taken into the anemone fish through feed. Furthermore, since Artemia swims in water and becomes suspended, there is an advantage that anemonefish larvae that are clownfish are easy to feed, unlike mixed feeds that settle. Therefore, anemone fish can be easily grown, and good-quality anemone fish can be easily propagated.

  Further, in this embodiment, anemonefish hatchling larvae are obtained by placing a clownfish parent fish under environmental water with a water temperature of 25 ° C. to 28 ° C. and a light irradiation time of 12 hours to 18 hours per day. . The anemone fish is housed in a breeding aquarium containing clean natural seawater, and the water temperature is adjusted to a range of 25 ° C. to 28 ° C. with an existing water temperature control device installed in the breeding aquarium. The light irradiation is adjusted, for example, by regularly turning on and off the aquarium lighting and indoor ceiling lighting with a timer, and adjusting the continuous lighting time of the aquarium lighting and indoor ceiling lighting to a range of 12 to 18 hours per day. To do. In addition, the illuminance at the time of lighting in the breeding water is preferably about 1,000 lux to 100,000 lux, for example, and the illuminance at the time of turning off the lighting is preferably, for example, 10 lux or less. The above water temperature and light irradiation conditions correspond to the breeding season of clownfish in natural waters and the water temperature and sunshine conditions of the breeding waters, and the clownfish parent fish lay eggs regularly at a frequency of about once every two weeks. repeat. Therefore, high-quality anemonefish eggs and hatched larvae can be stably obtained.

  In the influence evaluation test method of the present invention, a test target factor is given to the environmental water of anemone fish grown by the above method, and the influence of the test target factor on the anemone fish is examined. For example, eggs laid by clownfish parent fish by the above method hatch after the lights are turned off around the 9th to 10th days after the laying. The hatched larvae are collected and stored in clean natural seawater (hereinafter referred to as normal seawater) and those containing the test target substance in the natural seawater (hereinafter referred to as test seawater). Artemia is administered to the hatched larvae usually contained in seawater and the hatched larvae contained in the test seawater, respectively, by the above method. The survival rate and growth rate of the anemonefish hatchling larvae in normal seawater and the anemonefish hatchling larvae in the test seawater are compared, and the effects of the test substances on the saltwater fish are investigated.

  Since Artemia does not open for about one day after hatching, it is not easily affected by the test substance contained in the test seawater. Therefore, it is possible to accurately observe the influence of the test target substance on the anemone fish itself, which is the test target fish, without considering the effect of the test target substance on the feed organism. According to the present invention, it is possible to easily carry out an impact evaluation test for seawater fish including the initial development stage, which has been extremely difficult until now.

  A set of clownfish parent fish was housed and raised in a circulating filtration tank installed indoors. Circulating filtration water tank has a capacity of 180 liters, an acrylic breeding tank, a capacity of 80 liters filled with mesh plastic filter media, a pump ("RMD-40" manufactured by Iwaki Co., Ltd.), and a water temperature control device. (Lacy Co., Ltd. “RZ-250Y”), UV irradiation device (manufactured by TOKYO HOT Co., Ltd., output 30 W) and metal halide lamp aquarium illumination (Lacy Co., Ltd. “LUC-150”) Was used. The breeding tank was filled with clean natural seawater, a rock with a diameter of about 30 cm, and a sea anemone with a diameter of about 20 cm. The water temperature was adjusted to 25-28 ° C. with a water temperature adjusting device, the aquarium lighting and the indoor ceiling lighting were lit for 12-18 hours per day by a timer, and the remaining time was almost dark.

  As a result, as shown in FIG. 1, egg laying was repeated regularly over a long period of two years or more at a frequency of about once every two weeks. In order to hatch after the light is turned off around the 9th to 10th day after egg laying, a trap made of ghost net is provided in advance at the drain outlet side of the breeding tank, and the hatched larvae are introduced into the trap by the water flow. Larvae were collected. As a result, around 400 hatchling larvae could be obtained at intervals of about 2 weeks.

  Furthermore, the clownfish hatched larvae obtained by the above method were respectively accommodated in test seawater containing copper as a test target substance and normal seawater, and artemia was administered as a feed, and an initial life stage toxicity test was conducted over 2 weeks. The test seawater used five types of copper concentrations in seawater: 40 microgram / liter, 80 microgram / liter, 160 microgram / liter, 320 microgram / liter, and 640 microgram / liter.

  The results of the toxicity test are shown in FIG. The ◆ plot in Fig. 2 shows the time course of the survival rate of hatching larvae in normal seawater, and the ■ plot is the time course of the survival rate of hatching larvae in test seawater with a copper concentration of 40 micrograms / liter. The ● plot shows the time course of the survival rate of hatched larvae in test seawater with a copper concentration of 80 microgram / liter, and the ◇ plot shows hatching in the test seawater with a copper concentration of 160 microgram / liter The time course of the survival rate of the larvae is shown, the plot of □ shows the time course of the survival rate of the hatched larvae in the test seawater with a copper concentration of 320 microgram / liter, and the plot of ○ shows the copper concentration of 640 micrograms The time-dependent change of the survival rate of the hatching larva in 1 / liter test seawater is shown. From the results shown in FIG. 2, when the copper concentration in the seawater is up to about 320 microgram / liter, the survival rate is not different from the normal seawater or rather improved, but at the copper concentration of 640 microgram / liter, it is higher than that of the normal seawater. It was also found that the survival rate decreased.

  The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the gist of the present invention. For example, the effect evaluation test performed using anemone fish grown by the method of the present invention is not limited to a toxicity test in which a toxic substance to be tested is contained in environmental water. For example, using contaminated seawater in the test area as environmental water, or placing the environmental water tank in a test environment such as a vibration state, the survival rate of the anemonefish, growth rate, swimming disturbance, etc. You may investigate the influence of a test object factor.

It is a graph which shows transition of the number of hatching larvae obtained from 1 set of clownfish, a horizontal axis shows time passage (one scale is one month), and a vertical axis | shaft shows the number of hatching larvae. It is a graph which shows the result of the early life stage toxicity test with respect to the copper using the hatching larva of the clown fish, a horizontal axis shows the number of breeding days, and a vertical axis | shaft shows survival rate [%].

Claims (3)

A parent fish of anemone fish is placed in an environmental water with a water temperature of 25 ° C. to 28 ° C. and a light irradiation time of 12 hours to 18 hours per day, and the illuminance at the time of light irradiation in the environmental water is 1,000 lux to 100, 10000 lux, and the illuminance when not irradiating with light is 10 lux or less to obtain a hatched larvae of the anemonefish, and only the artemia before opening is administered to the anemonefish larvae instead of the rotifer To grow anemone fish. Into the anemone fish of anemonefish, toxic substances are contained in the environmental water of the anemonefish that has grown by administering only pre-opening Artemia instead of rotifer, or the environmental water is contaminated seawater, or the environmental water An impact evaluation test method characterized by giving a test object factor by vibrating a water tank and examining an influence of the test object factor on the anemonefish . Environmental water anemone such that grown by the method of claim 1 Symbol placement is contained toxic substances, or the environmental water and contaminated seawater, or give tested factors by vibrating the water tank of the environmental water, An influence evaluation test method characterized by examining the influence of the test target factor on the anemonefish.

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