Cephalopod rearing method, cephalopod rearing apparatus, protozoa prevention method, and protozoa extermination method
Provided herein is a method for breeding cephalopod larvae in a rearing tank having a water changing means. The method includes a water-changing period during which the ratio of water changed by the water-changing means per day is 200% or more relative to the quantity of water in the rearing tank in a floating breeding period of the cephalopod larvae.
1 . A cephalopod rearing method comprising rearing cephalopod larvae in a rearing tank comprising a water exchange mechanism,
wherein the cephalopod larvae are common octopus larvae, and
wherein a planktonic paralarval stage for the cephalopod larvae includes (i) a high water exchange rate period in which a water exchange rate relative to an amount of water in the rearing tank per day by a water exchange mechanism is 200% or more, and (ii) an adjustment period before the high water exchange rate period, in which the water exchange rate relative to the amount of water in the rearing tank per day by the water exchange mechanism is 90% or less.
2 . The cephalopod rearing method according to claim 1 , wherein the high water exchange rate period is set to include a period until the cephalopod larvae reach 15 days after hatching.
3 . The cephalopod rearing method according to claim 1 , wherein the high water exchange rate period is a continuous period of 12 hours or more.
4 . The cephalopod rearing method according to claim 1 , wherein the high water exchange rate period is set to a period after the cephalopod larvae reach 5 days after hatching.
5 . The cephalopod rearing method according to claim 1 , wherein the adjustment period is set to a period until the cephalopod larvae reach 10 days after hatching.
6 . The cephalopod rearing method according to claim 1 , wherein the water exchange mechanism is configured to discharge water in the vicinity of a bottom of water in the rearing tank.
7 . The cephalopod rearing method according to claim 1 , wherein the water exchange rate relative to the amount of water in the rearing tank per day by the water exchange mechanism during the adjustment period is 80% or less.
8 . A method of preventing protozoa occurrence in a rearing tank with cephalopod larvae, comprising rearing cephalopod larvae in the rearing tank having a water exchange mechanism,
wherein the cephalopod larvae are common octopus larvae, and
wherein a planktonic paralarval stage for the cephalopod larvae includes (i) a high water exchange rate period in which a water exchange rate relative to an amount of water in the rearing tank per day by the water exchange mechanism is 200% or more, and (ii) an adjustment period before the high water exchange rate period, in which the water exchange rate relative to the amount of water in the rearing tank per day by the water exchange mechanism is 90% or less,
thereby preventing protozoa occurrence in the rearing tank.
9 . The protozoa prevention method according to claim 8 , wherein the high water exchange rate period is set to include a period until the cephalopod larvae reach 15 days after hatching.
10 . The protozoa prevention method according to claim 8 , wherein the high water exchange rate period is a continuous period of 12 hours or more.
11 . The protozoa prevention method according to claim 8 , wherein the high water exchange rate period is set to a period after the cephalopod larvae reach 5 days after hatching.
12 . The protozoa prevention method according to claim 8 , wherein the adjustment period is set to a period until the cephalopod larvae reach 10 days after hatching.
13 . The protozoa prevention method according to claim 8 , wherein the water exchange mechanism is configured to discharge water in the vicinity of a bottom of water in the rearing tank.
14 . The protozoa prevention method according to claim 8 , wherein the protozoa is a ciliate.
15 . The protozoa prevention method according to claim 8 , wherein, in the planktonic paralarval stage, a density of protozoa of water in the rearing tank is controlled to 400 individuals/ml or less.
16 . The protozoa prevention method according to claim 8 , wherein the water exchange rate relative to the amount of water in the rearing tank per day by the water exchange mechanism during the adjustment period is 80% or less.
17 . A method of exterminating a protozoa in a rearing tank with cephalopod larvae, comprising rearing cephalopod larvae in the rearing tank having a water exchange mechanism,
wherein the cephalopod larvae are common octopus larvae, and
wherein a planktonic paralarval stage for the cephalopod larvae includes (i) a high water exchange rate period in which a water exchange rate relative to an amount of water in the rearing tank per day by the water exchange mechanism is 200% or more, and (ii) an adjustment period before the high water exchange rate period, in which the water exchange rate relative to the amount of water in the rearing tank per day by the water exchange mechanism is 90% or less,
thereby exterminating the protozoa in the rearing tank.
18 . The method according to claim 17 , wherein the high water exchange rate period is set to include a period until the cephalopod larvae reach 15 days after hatching.
19 . The method according to claim 17 , wherein the high water exchange rate period is a continuous period of 12 hours or more.
20 . The method according to claim 17 , wherein the high water exchange rate period is set to a period after the cephalopod larvae reach 5 days after hatching.
21 . The method according to claim 17 , wherein the adjustment period is set to a period until the cephalopod larvae reach 10 days after hatching.
22 . The method according to claim 17 , wherein the water exchange mechanism is configured to discharge water in the vicinity of a bottom of water in the rearing tank.
23 . The method according to claim 17 , wherein the protozoa is a ciliate.
24 . The method according to claim 17 , wherein, in the planktonic paralarval stage, a density of protozoa of water in the rearing tank is controlled to 400 individuals/ml or less.
25 . The method according to claim 17 , wherein the water exchange rate relative to the amount of water in the rearing tank per day by the water exchange mechanism during the adjustment period is 80% or less.