Aquatic life killing agent

Abstract

To provide an aquatic life killing agent capable of killing effectively aquatic life inhabiting in the bottom sand of a culture facility and becoming an intermediate host of viruses and bacteria.SOLUTION: Provided is an aquatic life killing agent that kills aquatic life inhabiting in the bottom sand of a culture facility, the agent comprising liquid containing peracetic acid.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an agent and a method for killing aquatic organisms. [Background technology]

[0002] Conventionally, aquaculture ponds or aquaculture cages (hereinafter collectively referred to as "aquaculture facilities") are cleaned after the shipment of cultured fish and shellfish. This cleaning includes plowing the bottom sand that appears when the stagnant water in the aquaculture facilities is discharged, and disinfecting or killing viruses and bacteria in the bottom sand with chemicals containing halogen elements such as chlorine and iodine, or with sunlight. This cleaning prevents the spread of infectious diseases caused by pathogenic viruses or bacteria among the fish and shellfish during the next aquaculture. For example, Japanese Patent Application Laid-Open No. 03-147727 (Patent Document 1) proposes improving the environment of shrimp aquaculture facilities by decomposing organic matter attached to the bottom sand of the aquaculture facilities using a hydrogen peroxide additive or peroxide, although the purpose is different from preventing the spread of infectious diseases. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 03-147727 Summary of the Invention [Problem to be solved by the invention]

[0004] Various wild aquatic organisms such as crustaceans and annelids live in the bottom sand of the aquaculture facility, and these aquatic organisms can be intermediate hosts for pathogenic viruses and pathogenic bacteria, and therefore have the risk of infecting the above-mentioned fish and shellfish with the above-mentioned pathogenic viruses and pathogenic bacteria. However, because the above-mentioned aquatic organisms have robust shells, they may not be sufficiently killed by chemicals containing halogen elements or disinfection by sunlight. Furthermore, the above-mentioned Patent Document 1 does not mention anything about wild aquatic organisms living in the bottom sand of the aquaculture facility. Therefore, a means for effectively killing the wild aquatic organisms living in the bottom sand to prevent the spread of infectious diseases caused by pathogenic viruses and pathogenic bacteria among fish and shellfish during aquaculture has not yet been realized, and its development is eagerly desired.

[0005] In view of the above, an object of the present invention is to provide an aquatic organism disinfectant and a method for effectively disinfecting aquatic organisms that live in the bottom sand of aquaculture facilities and serve as intermediate hosts for viruses and bacteria. [Means for solving the problem]

[0006] The present inventors have arrived at the present invention as a result of intensive research. That is, they focused on killing the above-mentioned aquatic organisms using peracetic acid, which has a higher oxidizing power than chlorine, hydrogen peroxide, etc. As a result, they found that when peracetic acid is used, aquatic organisms can be killed at a lower concentration and in a shorter time than conventional chemicals, and thus completed the present invention.

[0007] The present invention has the following characteristics. [1] The aquatic organism killing agent according to the present invention is an aquatic organism killing agent for killing aquatic organisms living in bottom sand of an aquaculture facility, and is composed of a liquid containing peracetic acid. [2] The aquatic organism is preferably a crustacean or an annelid. [3] The crustacean is at least one species selected from the group consisting of the Japanese sandworm, the Harman sandworm, and the sandworm, and the annelid is a worm such as a worm or a worm. It is preferable that the worm be at least one species selected from the group consisting of worms. [4] The sterilization method of the present invention is a sterilization method for sterilizing aquatic organisms living in bottom sand of an aquaculture facility, and includes a sterilization step of contacting the bottom sand of the aquaculture facility with a liquid containing peracetic acid. [5] The liquid preferably contains 10 mg / L or more of the peracetic acid. [6] The sterilization step preferably includes a preparation step of preparing the liquid by mixing the peracetic acid with fresh water or seawater. [7] The killing method preferably includes a tilling step of tilling the bottom sand, and the tilling step is preferably carried out at least either before, after or during the killing step. [8] The aquatic organisms are preferably crustaceans or annelids. [9] It is preferable that the crustacean is at least one species selected from the group consisting of the Japanese sandworm, the Harman sandworm, and the sandworm, and that the annelid is at least one species selected from the group consisting of the Lureworm and the Yamato sandworm. Effect of the Invention

[0008] According to the above, aquatic organisms that live in the bottom sand of aquaculture facilities and serve as intermediate hosts for viruses or bacteria can be effectively killed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention (hereinafter also referred to as "the present embodiment") will be described in more detail. In this specification, the notation in the form of "A to B" means the upper and lower limits of a range (i.e., A or more and B or less), and when no unit is stated for A and only a unit is stated for B, the unit of A and the unit of B are the same. In this specification, "seafood" means a general term for aquatic animals including fish and shellfish, seaweed, etc., and particularly means aquatic animals and seaweed that are edible for humans, such as fish, shellfish, shrimp, crab, octopus, squid, and sea urchin. The "seafood" of interest in this specification specifically refers to fish, shellfish, shrimp, etc. that are used in aquaculture.

[0010] [Aquatic life killer] The aquatic organism disinfectant according to the present embodiment is an aquatic organism disinfectant for disinfecting aquatic organisms living in bottom sand of aquaculture facilities, and is made of a liquid containing peracetic acid. The aquatic organism disinfectant having such characteristics can effectively disinfect aquatic organisms that may be intermediate hosts of pathogenic viruses and pathogenic bacteria by the oxidizing power of peracetic acid, thereby preventing the spread of infectious diseases caused by the pathogenic viruses and pathogenic bacteria among fish and shellfish during aquaculture.

[0011] In the following, in order to facilitate understanding of this embodiment, the case where the above-mentioned fish and shellfish are kuruma shrimp will be described as an example. However, the aquatic organism killer according to this embodiment can also be applied to aquaculture facilities that cultivate fish and shellfish other than kuruma shrimp. For example, the above-mentioned effects can be expected whether the above-mentioned fish and shellfish are saltwater fish or freshwater fish. In particular, the aquatic organism killer according to this embodiment can be expected to be highly effective when applied to aquaculture facilities that cultivate marine fish selected from Penaeus monodon, Tiger prawn, Blue crab, and Japanese prawn, in addition to kuruma shrimp.

[0012] Generally, kuruma shrimp farming is carried out under a farming cycle that involves the following first to third processes, which take about one year. First, in the first process, the farming facility is filled with seawater in order to release the kuruma shrimp juveniles for farming (about 3 to 4 months). Next, in the farming facility that has undergone the first process, the kuruma shrimp juveniles are released and the second process is carried out to grow the kuruma shrimp juveniles (about 5 to 6 months). When the kuruma shrimp have grown sufficiently in the second process, they are shipped (about one month). Next, in order to prepare for the next farming, the third process is carried out in which seawater is drained from the farming facility and the bottom sand is washed (about 2 to 3 months). The farming cycle begins with the first process being completed after the third process is completed. It is formed by:

[0013] The aquatic organism killer according to this embodiment can be applied to the bottom sand that appears when seawater is discharged from the aquaculture facility in the third process of the aquaculture cycle. This kills aquatic organisms living in the bottom sand of the aquaculture facility, thereby preventing the spread of infectious diseases caused by pathogenic viruses and pathogenic bacteria among fish and shellfish during aquaculture (the second process). In particular, the aquatic organism killer can kill aquatic organisms in place of conventional chemicals containing halogen elements such as chlorine and iodine, or together with the chemicals. Furthermore, the disinfection of the bottom sand by sunlight can be added at a time different from the washing work of the bottom sand using the aquatic organism killer in the third process, or can be performed in parallel with the washing work of the bottom sand using the aquatic organism killer.

[0014] <Aquaculture facilities> The aquatic organism killing agent according to this embodiment is an aquatic organism killing agent for killing aquatic organisms living in the bottom sand of the aquaculture facility as described above. In this specification, the term "aquaculture facility" refers to the general facilities for cultivating the above-mentioned fish and shellfish. In other words, the category of aquaculture facilities includes all facilities for cultivating the above-mentioned fish and shellfish, which have been conventionally called aquaculture ponds or aquaculture cages, as long as they have bottom sand. The aquatic organism killing agent can be applied to any aquaculture facility as long as it has bottom sand, without being limited by the installation area, size (area / volume) of the aquaculture facility, the type of water (freshwater or seawater) filling the facility, etc.

[0015] (Bottom sand) Furthermore, the aquatic organism killing agent can be applied to the bottom sand of the aquaculture facility without being limited by the type of soil, gravel, mud, etc. that constitutes the bottom sand.

[0016] <Aquatic organisms> The aquatic organism disinfectant according to this embodiment kills aquatic organisms living in the bottom sand of the aquaculture facility as described above. In this specification, "aquatic organisms" refers to invertebrates such as crustaceans and annelids that live in the bottom sand of the aquaculture facility, and in particular invertebrates that may be preyed upon by fish and shellfish cultivated in the aquaculture facility. In other words, the aquatic organisms are preferably crustaceans or annelids. Furthermore, the category of aquatic organisms includes microorganisms such as phytoplankton and zooplankton as long as they may be preyed upon by the fish and shellfish. In other words, in this specification, "aquatic organisms" refers to all organisms that live in the bottom sand of the aquaculture facility, carry pathogenic viruses or pathogenic bacteria, and may infect the fish and shellfish with the pathogenic viruses or pathogenic bacteria by being preyed upon by the fish and shellfish. In addition, the categories of "pathogenic virus" and "pathogenic microorganism" in this specification include all viruses, bacteria, fungi, protozoa, etc. that adversely affect the growth of the above-mentioned fish and shellfish, such as causing abnormalities in the above-mentioned fish and shellfish (e.g., the death of the above-mentioned fish and shellfish). Examples of the above-mentioned "pathogenic virus" and "pathogenic microorganism" include, but are not limited to, the PAV causative virus, Vibrio bacteria, Fusarium bacteria, etc.

[0017] (Crustaceans) The crustacean is preferably at least one selected from the group consisting of Japanese sand worm, Harman sand worm, and sand worm. These aquatic organisms are known to live in the bottom sand of aquaculture facilities and to be intermediate hosts of pathogenic viruses or pathogenic bacteria such as PAV causative virus, Vibrio bacteria, and Fusarium bacteria. Therefore, by effectively killing these aquatic organisms with the aquatic organism disinfectant, it is possible to prevent the spread of infectious diseases caused by the pathogenic viruses and pathogenic bacteria among fish and shellfish during aquaculture.

[0018] (annelid) The annelid is preferably at least one selected from the group consisting of Sebastiscus punctatus and Polyporus nigricans. These aquatic organisms are known to live in the bottom sand of aquaculture facilities and to be intermediate hosts of pathogenic viruses or bacteria such as PAV causative virus, Vibrio bacteria, and Fusarium bacteria. Therefore, by effectively killing these aquatic organisms with the aquatic organism disinfectant, it is possible to prevent the spread of infectious diseases caused by the pathogenic viruses and bacteria among fish and shellfish during aquaculture.

[0019] <Liquid containing peracetic acid> The aquatic organism killing agent according to the present embodiment is composed of a liquid containing peracetic acid as described above. The liquid containing peracetic acid can be applied as the aquatic organism killing agent without any particular limitation as long as it is a solution in which peracetic acid is dissolved in any solvent. For example, an aqueous solution of peracetic acid in which peracetic acid is dissolved in water can be exemplified. In particular, the aquatic organism killing agent can be various liquid compositions described later. Furthermore, the liquid containing peracetic acid may be a diluted aqueous solution in which the aqueous solution or liquid composition is appropriately diluted with fresh water or seawater in order to kill aquatic organisms living in the bottom sand of the aquaculture facility. Specifically, the liquid containing peracetic acid preferably contains 10 mg / L or more of the peracetic acid, and more preferably contains 200 mg / L or more and 600 mg / L or less of the peracetic acid, at the stage of contacting the bottom sand of the aquaculture facility. If the concentration of peracetic acid in the liquid is less than 10 mg / L, it may be impossible to kill aquatic organisms, or it may take an excessive amount of time to kill aquatic organisms, resulting in inefficiency (reduced workability). In addition, in the aquatic organism disinfectant according to this embodiment, it is not excluded to locally contact a liquid containing peracetic acid at a high concentration of 1 g / L or more with bottom sand of an aquaculture facility.

[0020] When the liquid containing peracetic acid is brought into contact with the bottom sand of the aquaculture facility, it is preferable to leave the bottom sand in that state for at least 3 minutes or more. When the liquid containing peracetic acid is brought into contact with the bottom sand of the aquaculture facility, it is also preferable to leave the bottom sand in that state for at least 30 minutes or more, more preferably to leave the bottom sand in that state for at least 1 hour or more, and even more preferably to leave the bottom sand in that state for at least 3 hours or more. This allows the aquatic organisms to be sufficiently killed. The higher the concentration of peracetic acid in the liquid, the shorter the time for which the bottom sand is left in that state after contacting it with the bottom sand of the aquaculture facility (for example, 3 minutes at 10 g / L), and the lower the concentration of peracetic acid in the liquid, the longer the time for which the bottom sand is left in that state after contacting it with the bottom sand of the aquaculture facility (for example, 3 hours at 50 mg / L).

[0021] (Peracetic acid) The peracetic acid in the liquid containing peracetic acid may be any conventionally known peracetic acid commercially available for industrial use without any particular limitation. Peracetic acid can exist in an aqueous solution while maintaining an equilibrium state between hydrogen peroxide and acetic acid. Therefore, as the liquid containing peracetic acid, for example, a liquid composition having a composition of 6% by mass of peracetic acid, 32% by mass of acetic acid, 8% by mass of hydrogen peroxide, and 54% by mass of water, and a liquid composition having a composition of 14 to 17% by mass of peracetic acid, 20 to 30% by mass of acetic acid, 10 to 15% by mass of hydrogen peroxide, and 38 to 56% by mass of water can be applied. The concentration of peracetic acid in the liquid containing peracetic acid can be measured by a conventionally known measurement method (for example, a titration method).

[0022] (Action and effect) The aquatic organism disinfectant of this embodiment can effectively kill or repel aquatic organisms that may be intermediate hosts for pathogenic viruses and pathogenic bacteria by the oxidizing power of peracetic acid, thereby preventing the spread of infectious diseases caused by the above-mentioned pathogenic viruses and pathogenic bacteria among seafood during aquaculture.

[0023] [How to kill] The sterilization method according to the present embodiment is a sterilization method for sterilizing aquatic organisms living in bottom sand of an aquaculture facility, and includes a sterilization step of contacting a liquid containing peracetic acid with the bottom sand of the aquaculture facility. The sterilization step preferably includes a preparation step of preparing the liquid by mixing the peracetic acid with fresh water or seawater. Furthermore, the sterilization method according to the present embodiment includes a cultivation step of plowing the bottom sand, and the cultivation step is preferably performed at least either before, after, or during the sterilization step. The sterilization method having such characteristics can effectively sterilize aquatic organisms that may be intermediate hosts for pathogenic viruses and pathogenic bacteria by the oxidizing power of peracetic acid, thereby preventing the spread of infectious diseases caused by the pathogenic viruses and pathogenic bacteria among fish and shellfish during aquaculture.

[0024] The terms "cultivation facility", "bottom sand", "aquatic organisms", "liquid containing peracetic acid" and "peracetic acid" defined in the sterilization method according to this embodiment have the same meaning as those terms explained in the above-mentioned [Aquatic organism sterilization agent] section, so the overlapping explanations will not be repeated. Therefore, the "aquatic organisms" to be sterilized by the sterilization method according to this embodiment are the same as the organisms explained in the above-mentioned [Aquatic organism sterilization agent] section. That is, the aquatic organisms sterilized by the sterilization method are preferably crustaceans or annelids, and the crustaceans are preferably at least one species selected from the group consisting of Nihon-namoguri, Harman-namoguri and Namoguri, and the annelids are preferably at least one species selected from the group consisting of Sebastiscus punctatus and Hime-Yamato-kawa-kai.

[0025] In the following, in order to facilitate understanding of the sterilization method according to this embodiment, a case will be described in which the fish and shellfish cultivated in the aquaculture facility are kuruma shrimp, as explained in the above section [Cide for aquatic organisms]. However, the sterilization method according to this embodiment can also be applied to aquaculture facilities that cultivate fish and shellfish other than kuruma shrimp.

[0026] <Killing process> The sterilization method according to this embodiment includes a sterilization step of contacting a liquid containing peracetic acid with the bottom sand of the aquaculture facility as described above. Specifically, in the sterilization method according to this embodiment, in order to sterilize aquatic organisms living in the bottom sand of the aquaculture facility, it is preferable to carry out the sterilization step in the third process of the aquaculture cycle described above. That is, in the sterilization step, it is preferable to contact a liquid containing peracetic acid with the bottom sand that appears when seawater is discharged from the aquaculture facility. This makes it possible to effectively sterilize aquatic organisms such as crustaceans and annelids living in the bottom sand of the aquaculture facility.

[0027] In the sterilization step, the liquid containing peracetic acid preferably contains 10 mg / L or more of peracetic acid at the stage of contacting with the bottom sand of the aquaculture facility. More preferably, the liquid containing peracetic acid contains 200 mg / L or more and 600 mg / L or less of peracetic acid at the stage of contacting with the bottom sand of the aquaculture facility. If the concentration of peracetic acid in the liquid is less than 10 mg / L, it may be impossible to kill aquatic organisms, or it may take an excessive amount of time to kill aquatic organisms, resulting in inefficiency (reduced workability). In the sterilization step, a liquid containing peracetic acid can be contacted with the bottom sand of the aquaculture facility instead of, or together with, conventional chemicals containing halogen elements such as chlorine and iodine. Furthermore, the sterilization step can be carried out at a time different from the disinfection of the bottom sand by sunlight in the third process, or can be carried out in parallel with the disinfection of the bottom sand by sunlight. In the sterilization step, it is not excluded to locally contact the liquid containing peracetic acid with the bottom sand of the aquaculture facility at a high concentration of 1 g / L or more.

[0028] In the sterilization step, when the liquid containing peracetic acid is brought into contact with the bottom sand of the aquaculture facility, it is preferable to leave the bottom sand in that state for at least 3 minutes or more. When the liquid is brought into contact with the bottom sand, it is preferable to leave the bottom sand in that state for at least 30 minutes or more, more preferably to leave the bottom sand in that state for at least 1 hour or more, and even more preferably to leave the bottom sand in that state for at least 3 hours or more. This allows a sufficient killing effect on the aquatic organisms to be obtained. The higher the concentration of peracetic acid in the liquid, the shorter the time for which the bottom sand is left in that state after contacting it with the bottom sand of the aquaculture facility (for example, 3 minutes at 10 g / L), and the lower the concentration of peracetic acid in the liquid, the longer the time for which the bottom sand is left in that state after contacting it with the bottom sand of the aquaculture facility (for example, 3 hours at 50 mg / L).

[0029] Here, the sterilization process can be carried out at any of the beginning, middle, and end of the third process. When the sterilization process is carried out at the beginning of the third process, sufficient time is available before water (seawater) is injected in the next first process, so that the sterilization effect of the liquid containing peracetic acid on aquatic organisms can be obtained more reliably. On the other hand, when the sterilization process is carried out at the end of the third process, the time until water (seawater) is injected in the next first process is short, so that the risk of pathogenic viruses or pathogenic bacteria contained in bird droppings or the like entering from the outside can be suppressed. Therefore, it is preferable to appropriately select the execution time of the sterilization process so that the sterilization effect of the liquid containing peracetic acid on aquatic organisms can be maximized in consideration of the surrounding environment of the aquaculture facility to which the sterilization method according to this embodiment is applied.

[0030] (preparation process) The sterilization step preferably includes a preparation step of preparing the liquid by mixing the peracetic acid with fresh water or sea water as described above. This allows a liquid containing peracetic acid with a concentration of 10 mg / L or more to be easily prepared. Specifically, in the preparation step, an aqueous solution of peracetic acid in which peracetic acid is dissolved in water, or any of the above-mentioned liquid compositions, is added together with fresh water or sea water to a pipe or the like for introducing fresh water or sea water into an aquaculture facility, so that the concentration of peracetic acid is 10 mg / L or more at the stage of contacting the bottom sand of the aquaculture facility, and the liquid containing peracetic acid can be easily prepared.

[0031] <Tillage process> The sterilization method according to the present embodiment preferably includes a tilling step of tilling the bottom sand as described above. In this case, the tilling step is carried out at least either before, after or during the sterilization step. This makes it easier for aquatic organisms in the bottom sand of the aquaculture facility to be exposed to the liquid containing peracetic acid.

[0032] For example, when the cultivation step is performed before the sterilization step, the bottom sand that has emerged as a result of seawater being discharged from the aquaculture facility can be cultivated before the liquid containing peracetic acid is introduced through the piping or the like to the bottom sand. In other words, after the bottom sand that has emerged as a result of seawater being discharged from the aquaculture facility is cultivated, the liquid containing peracetic acid is introduced through the piping or the like to the bottom sand. In this way, the sterilization step in which the bottom sand that has hardened through the second process is brought into contact with the liquid containing peracetic acid can be performed in a state in which it has been appropriately loosened through the cultivation step, and the liquid containing peracetic acid can be efficiently infiltrated into the aquatic organisms living in the bottom sand.

[0033] For example, when the cultivation step is carried out during the sterilization step, the bottom sand that has emerged as a result of seawater being discharged from the aquaculture facility can be cultivated while a liquid containing peracetic acid is introduced through the piping, etc. In this way, the bottom sand that has hardened through the second process can be loosened appropriately by the cultivation step while the sterilization step of contacting the bottom sand with the liquid containing peracetic acid can be carried out, so that the liquid containing peracetic acid can be efficiently infiltrated into the aquatic organisms living in the bottom sand.

[0034] For example, when the tilling step is carried out after the sterilization step, the bottom sand that has emerged as a result of the seawater being discharged from the aquaculture facility can be tilled after the liquid containing peracetic acid is introduced through the piping, etc. In this way, the bottom sand that has come into contact with the liquid containing peracetic acid in the sterilization step can be appropriately loosened by the tilling step, so that the liquid containing peracetic acid can be sufficiently permeated into the bottom sand, thereby efficiently exposing the liquid containing peracetic acid to the aquatic organisms living in the bottom sand.

[0035] The plowing process can be performed before and after the killing process, or before, during, and after the killing process. The plowing process can be performed during and after the killing process, or before and during the killing process. Specifically, the plowing process can be performed by using heavy machinery to plow the bottom sand that appears when seawater is drained from the aquaculture facility.

[0036] Here, the inventors have confirmed that the concentration of peracetic acid in a liquid containing peracetic acid decreases when it comes into contact with bottom sand, as it reacts with organic matter attached to the bottom sand and is decomposed, but that by containing 10 mg / L or more of peracetic acid in the liquid containing peracetic acid at the stage of contacting the bottom sand of the aquaculture facility, aquatic organisms can be effectively killed. However, if the concentration of peracetic acid in the bottom sand is measured by a known method in the above killing process and an excessive decrease in the concentration of peracetic acid is found, an additional liquid containing peracetic acid can be added to the bottom sand as appropriate. On the other hand, if the concentration of peracetic acid is too high and its odor, etc. adversely affects the working environment of the aquaculture facility, an enzyme required for decomposing peracetic acid or a reducing substance such as sodium sulfite can be added to the bottom sand as appropriate in the above killing process.

[0037] (Action and effect) The sterilization method according to this embodiment can effectively sterilize aquatic organisms that may be intermediate hosts for pathogenic viruses and pathogenic bacteria by the oxidizing power of peracetic acid, thereby preventing the spread of infectious diseases caused by pathogenic viruses and pathogenic bacteria among seafood during aquaculture. EXAMPLES

[0038] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. In Tables 1 to 4 below, "NaClO" means an aqueous solution of sodium hypochlorite, and "H 2 O 2 " stands for aqueous hydrogen peroxide solution, and "PAA" stands for a liquid containing peracetic acid (aquatic organism killer). In the "Lethality" column, "Y" means that the organism was killed, and "N" means that the organism was not killed. The presence or absence of "lethality" was determined based on the behavior of the aquatic organisms when they were returned to seawater.

[0039] [Example 1: Direct exposure to Japanese sand crickets] In this example, a direct exposure test was conducted as described below to examine the effectiveness of killing Japanese sand slugs, a crustacean that lives in the bottom sand of aquaculture facilities, using a liquid containing peracetic acid.

[0040] <Preparation of liquid containing peracetic acid> A liquid composition (manufactured by Katayama Chemical Industry Research Institute Co., Ltd.) with a composition of 5.6% by mass of peracetic acid, 32.3% by mass of acetic acid, 7.8% by mass of hydrogen peroxide, and 54.3% by mass of water was prepared as a raw material for preparing a liquid containing peracetic acid. The liquid composition was diluted with natural seawater (Wakayama Prefecture) so that the concentration of peracetic acid became 1000 mg / L, thereby preparing a liquid containing peracetic acid.

[0041] Furthermore, as a chemical to compare the effectiveness of the liquid containing peracetic acid, 12% by mass sodium hypochlorite (effective chlorine concentration of 5% by mass or more, manufactured by Kishida Chemical Co., Ltd.) was used. A sodium hypochlorite aqueous solution was prepared by diluting the natural seawater to a chlorine concentration of 1000 mg / L. A hydrogen peroxide aqueous solution was also prepared by diluting 30 mass% hydrogen peroxide (manufactured by Kishida Chemical Co., Ltd.) with the natural seawater to a hydrogen peroxide concentration of 1000 mg / L.

[0042] Next, Samples 1-1 to 1-3 were prepared from the aqueous sodium hypochlorite solution, Samples 2-1 to 2-3 were prepared from the aqueous hydrogen peroxide solution, and Samples 3-1 to 3-3 were prepared from the liquid containing peracetic acid. Furthermore, Samples 4-1 to 4-3 were prepared from seawater as a control.

[0043] <Direct exposure to Japanese sand crickets> A number of Japanese sand crickets (body weight 2.49 to 3.40 g) corresponding to the number of samples of the above-mentioned drug were prepared. The above-mentioned samples 1-1 to 1-3, 2-1 to 2-3, 3-1 to 3-3, and 4-1 to 4-3 were directly sprinkled on the Japanese sand crickets to confirm whether or not the Japanese sand crickets were killed by these samples. Furthermore, if the Japanese sand crickets were killed, the time from sprinkling the sample to killing the Japanese sand crickets was measured. The results are shown in Table 1. In Table 1, "lethal time" means the time from sprinkling the sample to killing the Japanese sand crickets.

[0044] [Table 1]

[0045] <Consideration> According to Table 1, it can be seen that a liquid containing peracetic acid is more effective in killing the Japanese sand cricket than an aqueous solution of sodium hypochlorite and an aqueous solution of hydrogen peroxide.

[0046] Example 2: Direct exposure to ursoids In this example, a direct exposure test was conducted as follows to examine the effectiveness of killing the annelid worm, a type of worm that lives in the bottom sand of aquaculture facilities, using a liquid containing peracetic acid.

[0047] Specifically, in the same manner as in Example 1, samples 5-1 to 5-3 made of an aqueous solution of sodium hypochlorite, samples 6-1 to 6-3 made of an aqueous solution of hydrogen peroxide, and samples 7-1 to 7-3 made of a liquid containing peracetic acid were prepared. Furthermore, samples 8-1 to 8-3 made of seawater were also prepared as a control. Next, a number of scleractinian worms (weight 0.61 to 0.85 g) corresponding to the number of samples of the above-mentioned drugs were prepared. The above-mentioned samples 5-1 to 5-3, samples 6-1 to 6-3, samples 7-1 to 7-3, and samples 8-1 to 8-3 were directly sprinkled on the scleractinian worms to confirm whether or not the scleractinian worms were killed by these samples. Furthermore, if the scleractinian worms were killed, the time from sprinkling the samples until the scleractinian worms were killed was measured. The results are shown in Table 2. In addition, the "lethal time" in Table 2 means the time from sprinkling the samples until the scleractinian worms were killed.

[0048] [Table 2]

[0049] <Consideration> According to Table 2, it can be seen that the liquid containing peracetic acid is more effective in killing worms than the aqueous sodium hypochlorite solution and the aqueous hydrogen peroxide solution. In particular, the liquid containing peracetic acid was able to kill worms in a shorter time than the aqueous sodium hypochlorite solution.

[0050] [Example 3: Examination of effective concentration (for Japanese sand cricket)] In this example, based on the results of Example 1, a direct exposure test was conducted as described below to examine the appropriate concentration of peracetic acid in a liquid containing peracetic acid for killing Japanese sand crickets using the liquid containing peracetic acid.

[0051] <Preparation of liquids containing peracetic acid having predetermined concentrations> A liquid composition (manufactured by Katayama Chemical Industry Research Institute Co., Ltd.) with a composition of 5.6% by mass of peracetic acid, 32.3% by mass of acetic acid, 7.8% by mass of hydrogen peroxide, and 54.3% by mass of water was prepared as a raw material for preparing a liquid containing peracetic acid. The liquid composition was diluted with natural seawater (Wakayama Prefecture) so that the concentration of peracetic acid was 25 mg / L, thereby preparing a first liquid containing peracetic acid.

[0052] Further, in the same manner as the preparation of the first peracetic acid-containing liquid, a second peracetic acid-containing liquid having a peracetic acid concentration of 50 mg / L, a third peracetic acid-containing liquid having a peracetic acid concentration of 75 mg / L, a fourth peracetic acid-containing liquid having a peracetic acid concentration of 100 mg / L, a fifth peracetic acid-containing liquid having a peracetic acid concentration of 200 mg / L, a sixth peracetic acid-containing liquid having a peracetic acid concentration of 400 mg / L, a seventh peracetic acid-containing liquid having a peracetic acid concentration of 600 mg / L, and an eighth peracetic acid-containing liquid having a peracetic acid concentration of 800 mg / L were each prepared.

[0053] Next, samples 9-1 to 9-3 were prepared, each consisting of the first liquid containing peracetic acid, samples 10-1 to 10-3 consisting of the second liquid containing peracetic acid, samples 11-1 to 11-3 consisting of the third liquid containing peracetic acid, samples 12-1 to 12-3 consisting of the fourth liquid containing peracetic acid, samples 13-1 to 13-3 consisting of the fifth liquid containing peracetic acid, samples 14-1 to 14-3 consisting of the sixth liquid containing peracetic acid, samples 15-1 to 15-3 consisting of the seventh liquid containing peracetic acid, and samples 16-1 to 16-3 consisting of the eighth liquid containing peracetic acid.

[0054] <Direct exposure to Japanese sand crickets> The number of Japanese sand crickets (body weight 3.55 to 3.90 g) corresponding to the number of samples of the above-mentioned drug were prepared. The above-mentioned samples 9-1 to 9-3, 10-1 to 10-3, 11-1 to 11-3, 12-1 to 12-3, 13-1 to 13-3, 14-1 to 14-3, 15-1 to 15-3, and 16-1 to 16-3 were directly sprinkled on the Japanese sand crickets to confirm whether the Japanese sand crickets were killed by these samples. Furthermore, when the Japanese sand crickets were killed, the time from sprinkling the sample to killing the Japanese sand crickets was measured. The results are shown in Table 3. In addition, the "lethal time" in Table 3 means the time from sprinkling the sample to killing the Japanese sand crickets.

[0055] [Table 3]

[0056] <Consideration> According to Table 3, it can be seen that the concentration of peracetic acid in the liquid containing peracetic acid that is appropriate for killing Japanese sand worms is 50 mg / L or more (mortality rate 67%). When the concentration of peracetic acid in the liquid containing peracetic acid is 75 mg / L or more, the Japanese sand worms are killed with a 100% probability.

[0057] [Example 4: Study of effective concentration (for urticaria)] In this example, based on the results of Example 2, a direct exposure test was conducted in the same manner as in Example 3 to examine the appropriate concentration of peracetic acid in a liquid containing peracetic acid for killing worms using the liquid containing peracetic acid.

[0058] <Preparation of liquids containing peracetic acid having predetermined concentrations> The same liquid composition as that prepared in Example 3 was diluted with natural seawater (Wakayama Prefecture) so that the concentration of peracetic acid became 5 mg / L, thereby preparing a ninth liquid containing peracetic acid.

[0059] Further, in the same manner as the preparation of the ninth liquid containing peracetic acid, a tenth liquid containing peracetic acid having a peracetic acid concentration of 10 mg / L, an eleventh liquid containing peracetic acid having a peracetic acid concentration of 15 mg / L, a twelfth liquid containing peracetic acid having a peracetic acid concentration of 25 mg / L, a thirteenth liquid containing peracetic acid having a peracetic acid concentration of 50 mg / L, a fourteenth liquid containing peracetic acid having a peracetic acid concentration of 75 mg / L, a fifteenth liquid containing peracetic acid having a peracetic acid concentration of 100 mg / L, a sixteenth liquid containing peracetic acid having a peracetic acid concentration of 200 mg / L, a seventeenth liquid containing peracetic acid having a peracetic acid concentration of 400 mg / L, an eighteenth liquid containing peracetic acid having a peracetic acid concentration of 600 mg / L, and a nineteenth liquid containing peracetic acid having a peracetic acid concentration of 800 mg / L were each prepared.

[0060] Next, samples 17-1 to 17-3 each consisting of the ninth liquid containing peracetic acid, samples 18-1 to 18-3 each consisting of the tenth liquid containing peracetic acid, samples 19-1 to 19-3 each consisting of the eleventh liquid containing peracetic acid, samples 20-1 to 20-3 each consisting of the twelfth liquid containing peracetic acid, samples 21-1 to 21-3 each consisting of the thirteenth liquid containing peracetic acid, samples 22-1 to 22-3 each consisting of the fourteenth liquid containing peracetic acid, samples 23-1 to 23-3 each consisting of the fifteenth liquid containing peracetic acid, and samples 24-1 to 24-3 each consisting of the sixteenth liquid containing peracetic acid were prepared. Samples 25-1 to 25-3 made of the 17th liquid containing peracetic acid, Samples 26-1 to 26-3 made of the 18th liquid containing peracetic acid, and Samples 27-1 to 27-3 made of the 19th liquid containing peracetic acid were prepared.

[0061] <Direct exposure to worms> A number of sclerotinia (body weight 0.50 to 0.75 g) corresponding to the number of samples of the above-mentioned drugs were prepared. The above-mentioned samples 17-1 to 17-3, 18-1 to 18-3, 19-1 to 19-3, 20-1 to 20-3, 21-1 to 21-3, 22-1 to 22-3, 23-1 to 23-3, 24-1 to 24-3, 25-1 to 25-3, 26-1 to 26-3, and 27-1 to 27-3 were directly sprinkled on the sclerotinia to confirm whether the sclerotinia were killed by these samples. Furthermore, if the sclerotinia were killed, the time from sprinkling the sample until the sclerotinia were killed was measured. The results are shown in Table 4. In addition, the "lethal time" in Table 4 means the time it takes for the lugworms to be killed after the sample is sprinkled on them.

[0062] [Table 4]

[0063] <Consideration> According to Table 4, it can be seen that the concentration of peracetic acid in the liquid containing peracetic acid that is appropriate for killing the worms is 10 mg / L or more (mortality rate 67%). When the concentration of peracetic acid in the liquid containing peracetic acid is 15 mg / L or more, the worms are killed with a 100% probability.

[0064] [Example 5: Effectiveness test simulating the environment in the bottom sand of an aquaculture facility] In this example, the following effectiveness test was conducted to investigate whether a liquid containing peracetic acid of a similar nature to that actually present in the bottom sand of an aquaculture facility can kill Japanese sand crickets.

[0065] <Preparation of liquid containing peracetic acid> As a raw material for preparing a liquid containing peracetic acid, a liquid composition having a composition of 5.6% by mass of peracetic acid, 32.3% by mass of acetic acid, 7.8% by mass of hydrogen peroxide, and 54.3% by mass of water (Kata Corporation) was used. A liquid containing peracetic acid was prepared by diluting the liquid composition with natural seawater (Wakayama Prefecture) so that the concentration of peracetic acid was 10,000 mg / L.

[0066] Furthermore, as a drug for comparing the effectiveness of the liquid containing peracetic acid, a sodium hypochlorite aqueous solution was prepared by diluting 12% by mass sodium hypochlorite (effective chlorine concentration of 5% by mass or more, manufactured by Kishida Chemical Co., Ltd.) with the above natural seawater to a chlorine concentration of 10,000 mg / L. A hydrogen peroxide aqueous solution was also prepared by diluting 30% by mass hydrogen peroxide (manufactured by Kishida Chemical Co., Ltd.) with the above natural seawater to a hydrogen peroxide concentration of 10,000 mg / L.

[0067] Next, Samples 28-1 to 28-3 were prepared from the above-mentioned sodium hypochlorite aqueous solutions, Samples 29-1 to 29-3 were prepared from the above-mentioned hydrogen peroxide aqueous solutions, and Samples 30-1 to 30-3 were prepared from liquids containing peracetic acid. Furthermore, Samples 31-1 to 31-3 were prepared from seawater as blanks.

[0068] <Preparing the environment in the bottom sand of the aquaculture facility> A sea sand layer measuring 65 mm in diameter and 250 mm in height was formed by placing 1,000 g of natural sea sand (produced in Wakayama Prefecture) into a cylindrical acrylic pipe with an inner diameter of 65 mm, and this was prepared as the bottom sand environment for the aquaculture facility.

[0069] <Preparation of the form of liquid containing peracetic acid present in the bottom sand of the aquaculture facility> The above samples 28-1 to 28-3, 29-1 to 29-3 and 30-1 to 30-3 were each immersed in the sea sand layer in the cylindrical acrylic piping, and then each sample that had passed through the sea sand layer was collected, thereby obtaining the characteristics of the liquid containing peracetic acid present in the bottom sand of the aquaculture facility (samples 30-1 to 30-3 after passing through the sea sand layer), the characteristics of the sodium hypochlorite aqueous solution (samples 28-1 to 28-3 after passing through the sea sand layer), and the characteristics of the hydrogen peroxide aqueous solution (samples 29-1 to 29-3 after passing through the sea sand layer).

[0070] The concentrations of peracetic acid in the form of liquid containing peracetic acid present in the bottom sand of the aquaculture facility (samples 30-1 to 30-3 after passing through the above-mentioned sea sand layer), the chlorine concentrations in the form of sodium hypochlorite aqueous solutions (samples 28-1 to 28-3 after passing through the above-mentioned sea sand layer), and the hydrogen peroxide concentrations in the form of hydrogen peroxide aqueous solutions (samples 29-1 to 29-3 after passing through the above-mentioned sea sand layer) are each shown in the "Concentration after passing" section of Table 4.

[0071] <Exposure to Japanese sand crickets> A number of Japanese sand crickets (body weight 2.60-3.50g) corresponding to the number of samples of the above-mentioned drug were prepared. Samples 28-1 to 28-3 after passing through the above-mentioned sea sand layer, Samples 29-1 to 29-3 after passing through the above-mentioned sea sand layer, Samples 30-1 to 30-3 and Samples 31-1 to 31-3 after passing through the above-mentioned sea sand layer were sprinkled on the above-mentioned Japanese sand crickets to confirm whether or not the Japanese sand crickets were killed by these samples. Furthermore, if the Japanese sand crickets were killed, the time from sprinkling the sample to killing the Japanese sand crickets was measured. The results are shown in Table 5. In Table 5, "lethal time" means the time from sprinkling the sample to killing the Japanese sand crickets.

[0072] [Table 5]

[0073] <Consideration> According to Table 5, the concentration of peracetic acid in a liquid containing peracetic acid decreases upon contact with the bottom sand of the aquaculture facility, but even in this case, it can be seen that a liquid containing peracetic acid is more effective in killing Japanese sand crabs than an aqueous solution of sodium hypochlorite and an aqueous solution of hydrogen peroxide.

[0074] Although the embodiments and examples of the present invention have been described above, it is intended from the beginning that the features of the respective embodiments and examples may be appropriately combined.

[0075] The embodiments and examples disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is defined by the claims, not by the above-described embodiments and examples, and is intended to include all modifications within the scope and meaning equivalent to the claims.

Claims

[Claim 1] An aquatic organism killing agent for killing aquatic organisms living in bottom sand of an aquaculture facility, comprising: An aquatic organism killing agent comprising a liquid containing peracetic acid.

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