Shellfish cultivation method and shellfish cultivation apparatus

Abstract

To provide a shellfish cultivation method and a shellfish cultivation apparatus for efficiently cultivating shellfish.SOLUTION: Shellfish are cultivated using a shellfish cultivation apparatus. In this case, in a shellfish cultivation apparatus 10A, young shellfish are settled on a plurality of first attachment plates 11 arranged at predetermined intervals to perform first cultivation, a second attachment plate 15 is disposed with respect to the first attachment plate 11, and highly active young shellfish that have moved within a switching timing are extracted using the second attachment plate 15, young shellfish remaining on the first attachment plate 11 are thinned out, and second cultivation is performed using the highly active young shellfish on the second attachment plate 15.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a shellfish farming method and shellfish farming apparatus for farming shellfish such as abalone. [Background technology]

[0002] Land-based aquaculture of shellfish such as abalone is being considered for the purpose of ensuring sustainable marine resources (for example, Patent Document 1). In the technology described in this document, algae are cultured by placing them in culture water for culturing the algae. The cultured algae are then supplied to culture water that contains the shellfish to be cultured and a calcium silicate-containing material. The shellfish are cultured in the culture water to which the algae have been supplied.

[0003] Furthermore, in abalone farming, land-based recirculating aquaculture, which uses seawater repeatedly, is also being investigated (for example, Non-Patent Document 1). The technology described in this document achieves a faster growth rate than in natural marine areas by maintaining the pH of the rearing water at 8.0 or higher and the water temperature at 17°C or lower.

[0004] Furthermore, if shellfish are raised too close together, they may suffer from food and oxygen shortages and become susceptible to disease and parasites. Therefore, efforts have been made to ensure sufficient space between individuals (see, for example, Patent Document 2). The scallop farming cages in this document are composed of multiple vertically connected rearing units, each equipped with a rearing chamber with a bottom net to catch juvenile shellfish that fall from the attachment net, and side nets that continuously cover the sides of the attachment chamber and the rearing chamber. Furthermore, thinning out the shells can be used to ensure sufficient space between the shells. This thinning ensures that each shellfish receives sufficient food and oxygen. This improves the growth rate, thereby increasing the yield per unit area. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-156404 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-35077 [Non-patent literature]

[0006] [Non-Patent Document 1] Yoshinori Oshima et al., "Research on recirculating land-based abalone aquaculture", [online], December 2020, Obayashi Corporation Technical Research Institute Report, No. 84, pp. 1-6 [Retrieved February 25, 2024], Internet<URL:https: / / www.obayashi.co.jp / technology / shoho / 084 / 2020_084_32.pdf> Summary of the Invention [Problem to be solved by the invention]

[0007] However, thinning is time-consuming, requiring selective selection of healthy shellfish, and care must be taken to avoid damaging the shellfish. [Means for solving the problem]

[0008] A shellfish farming method that solves the above problem involves the following steps: in the shellfish farming device, the first farming is carried out by allowing the young shellfish to settle on a plurality of first attachment plates arranged at a predetermined interval; a second attachment plate is arranged in relation to the first attachment plates; the second attachment plate is used to extract highly active young shellfish that have moved within the switching timing; the young shellfish remaining on the first attachment plate are thinned; and the second farming is carried out using the highly active young shellfish on the second attachment plate.

[0009] A shellfish farming device that solves the above problem comprises a first unit having a plurality of first attachment plates arranged at a predetermined interval and on which the young shellfish settle, and a first support part that secures the plurality of first attachment plates; and a second unit having a plurality of second attachment plates that are inserted between the first attachment plates and arranged at intervals that allow the young shellfish to move from the first attachment plates within the switching timing, and a second support part that secures the plurality of second attachment plates. [Effects of the Invention]

[0010] According to the present disclosure, shellfish can be cultivated efficiently. [Brief explanation of the drawings]

[0011] [Figure 1] 1A and 1B are explanatory diagrams of a shellfish farming device according to an embodiment, in which (a) is an explanatory diagram of the first rearing configuration, (b) is an explanatory diagram of the configuration during the transfer period, and (c) is an explanatory diagram of the second rearing configuration. [Figure 2] FIG. 2 is an explanatory diagram of a processing procedure according to an embodiment. [Figure 3] FIG. 1 is an explanatory diagram of the average shell length of abalone in an embodiment based on the number of days after settlement. [Figure 4] FIG. 1 is an explanatory diagram of the average shell length of abalone in an embodiment according to the number of days after feeding. [Figure 5] An explanatory diagram of a modified shellfish farming device, where (a) is the first unit, (b) is the configuration during the first breeding stage, (c) is the insertion of the second unit, and (d) is the configuration during the second breeding stage. DETAILED DESCRIPTION OF THE INVENTION

[0012] An embodiment of a shellfish farming method and apparatus will be described below with reference to Figures 1 to 4. In this embodiment, abalone, which feed on diatoms, are farmed on land in a completely closed circulation environment.

[0013] As shown in FIG. 1(a), a shellfish farming apparatus 10A has a plurality of first attachment plates 11 arranged at predetermined intervals. Specifically, the plurality of first attachment plates 11 are supported by supports 12 at predetermined intervals. Diatoms, which are feed for abalone, grow abundantly on the first attachment plates 11. In this embodiment, 60 first attachment plates 11 form one set. This one set is used as one section for rearing.

[0014] (Breeding Procedures) The abalone rearing procedure will be explained using Figure 2. First, seedling collection is carried out (Step S1). Specifically, fertilized eggs are placed in an aquarium, and the abalone larvae that hatch and start swimming around are collected.

[0015] Next, the larvae are attached (step S2). Specifically, the floating larvae are allowed to settle on the first attachment plate 11 on which diatoms grow abundantly. Next, the first rearing is carried out (step S3). Specifically, the young oysters are reared using diatoms. In this case, the diatoms on the attachment plate when they first settle on the bottom are almost completely consumed. If the amount of diatoms is low, diatoms can be added by placing a diatom mat on the first attachment plate 11 or scattering diatom powder.

[0016] Next, shell length is determined periodically (step S4). Diatoms are fed to the juvenile oysters, and they are grown on the first attachment plate 11. The shell length is measured, and the average shell length is compared with a reference value (2 mm in this embodiment).

[0017] Next, if the average shell length exceeds the reference value, a new attachment plate is inserted (step S5). Here, a new attachment plate (second attachment plate) is inserted between the first attachment plates 11 that have already been placed. Specifically, as shown in Figure 1(b), shellfish cultivation apparatus 10A is disassembled, and new second attachment plates 15 are inserted between adjacent first attachment plates 11 to construct shellfish cultivation apparatus 10B. In this embodiment, the spacing between the attachment plates of shellfish cultivation apparatus 10B is the same as that of shellfish cultivation apparatus 10A. This spacing is the distance that active oysters (highly active oysters) can move from the time they are inserted onto second attachment plates 15 until the time to switch to thinning. In this way, two sets of shellfish cultivation apparatus 10B are created.

[0018] Next, a second rearing is carried out on a new attachment plate (step S6). When the diatoms on the first attachment plate 11 decrease, the juvenile oysters begin to move to the second attachment plate 15. The system then waits until the switching timing when a predetermined number (proportion) of highly active juvenile oysters have moved to the second attachment plate 15. The shellfish farming device 10B is disassembled, and the second attachment plate 15 is removed.

[0019] Next, as shown in Figure 1(c), one set of shellfish cultivation apparatus 10C is constructed by connecting the second attachment plates 15 with the support parts 12. In this embodiment, the spacing between the attachment plates of shellfish cultivation apparatus 10C is the same as the spacing between the attachment plates of shellfish cultivation apparatus 10A.

[0020] Next, the animals are fed a compound feed (step S7), which contains a protein source (fish meal, soybean meal, wheat flour, etc.), lipids (fish oil, vegetable oil, etc.), carbohydrates (starch, sugars, etc.), vitamins, and minerals (calcium, phosphorus, magnesium, iron, etc.).

[0021] (Action of this embodiment) Healthy shellfish are very active, so by moving to the second attachment plate 15 where there is plenty of food, they are separated into highly active young shellfish and less active young shellfish.

[0022] (Effects of this embodiment) (1) In this embodiment, if the shell length exceeds the reference value, a new attachment plate is inserted and then movement is waited for (Step S5). This allows healthy, active, highly active juvenile oysters to be moved to the second attachment plate 15 where there is an abundance of food and extracted.

[0023] Figure 3 is a graph showing a comparison of the average shell length between the remaining individuals and the highly active juvenile oysters. The square symbols represent the average shell length on the first attachment plate 11, and the circles represent the average shell length of the individuals (highly active juvenile oysters) that spontaneously migrated to the second attachment plate 15. It can be seen that the highly active oysters on the second attachment plate 15 had a faster growth rate than the remaining individuals on the first attachment plate 11.

[0024] (2) In this embodiment, the shellfish are grown on a new attachment plate (step S6). This allows the shellfish that have moved to be selected and thinned out. Since the shellfish move spontaneously, damage to the shellfish during thinning can be reduced.

[0025] (3) In this embodiment, the oysters are raised on a compound feed (step S7). This allows for early switching to a compound feed that is nutritionally superior to diatoms, thereby promoting growth. In particular, since the feed is given to healthy oysters after thinning, it is possible to improve survival rates and yields.

[0026] Figure 4 is a graph comparing the average shell length of individuals fed only diatoms and those switched to a formulated diet. The squares represent the average shell length of individuals fed only diatoms, and the circles represent the average shell length of individuals switched to a formulated diet. It can be seen that the growth rate of individuals switched to a formulated diet is faster than that of individuals fed only diatoms.

[0027] This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility. In the above embodiment, the shellfish farming apparatus is applied to abalone farming. However, the apparatus is not limited to abalone and can be used for any shellfish that grows by feeding.

[0028] In the above embodiment, shell length is determined periodically (step S4). Here, for example, shell length may be measured by image recognition using images of the juvenile oysters on the first attachment plate 11 taken with a camera. In particular, since the color of abalone's shells grows reddish while they are feeding on attached diatoms, this can be distinguished using a color filter.

[0029] In the above embodiment, the shellfish farming apparatus 10A has a plurality of first attachment plates 11 arranged at a predetermined interval by support parts 12. Alternatively, two shellfish farming apparatuses may be used, each with its own first attachment plate arranged at a predetermined interval.

[0030] As shown in Fig. 5(a), first units 20 and 21 are used. In the first unit 20, a plurality of first attachment plates 111 are fixed to a support portion 201 (first support portion). In the first unit 21, a plurality of first attachment plates 112 are fixed to a support portion 211 (first support portion). Furthermore, the support portion 201 is provided with a notch J1 (fitting portion) into which the first attachment plates 112 can be inserted. The support portion 211 is also provided with a notch (not shown) into which the first attachment plates 111 can be inserted.

[0031] As shown in Figure 5(b), the first unit 20 and the first unit 21 are combined to form a shellfish farming apparatus 23. This shellfish farming apparatus 23 is used to cultivate young shellfish. When the second attachment plate is inserted between the first attachment plates, the shellfish farming device 23 is disassembled into the first units 20 and 21.

[0032] Then, as shown in Figure 5(c), second units 30 and 31 are used. In the second unit 30, a plurality of second attachment plates 151 are fixed to a support portion 301 (second support portion). In addition, in the second unit 31, a plurality of second attachment plates 152 are fixed to a support portion 311 (second support portion). Furthermore, the support portions 301 and 311 are provided with notches J1 (fitting portions) into which the second attachment plates 152 and 151 can be inserted. By inserting the second unit 30 into the first unit 20 and the second unit 31 into the first unit 21, two sets of shellfish farming devices 24 are formed.

[0033] When cultivating on a new attachment plate (step S6), the second units 30 and 31 are removed from the two sets of shellfish culturing devices 24 and are joined together at the mating portions. As shown in FIG. 5(d), a shellfish farming device 25 consisting of second units 30 and 31 is created. This allows for the combination of shellfish farming devices with multiple attachment plates integrated together, making it possible to thin out the fish efficiently.

[0034] In the above embodiment, the second rearing is performed using a compound feed (step S7). The second rearing after thinning is not limited to using a compound feed. In the above embodiment, the switching timing was determined to be when a predetermined percentage of juvenile oysters move to the second attachment plate 15. A predetermined time may also be used as the switching timing. Here, the predicted time when a predetermined percentage of highly active oysters will move from the first attachment plate 11 to the second attachment plate 15 in search of food is used as the switching timing. [Explanation of symbols]

[0035] 10A, 10B, 10C, 22, 23, 24, 25...shellfish farming device, 20, 21...first unit, 30, 31...second unit, 11, 111, 112...first attachment plate, 15, 151, 152...second attachment plate, 12, 201, 211, 301, 311...support part.

Claims

1. A method for raising shellfish using a shellfish farming device, comprising: In the shellfish farming device, the first cultivation is carried out by attaching the young shellfish to a plurality of first attachment plates arranged at predetermined intervals, a second attachment plate is disposed relative to the first attachment plate; Using the second attachment plate, extract highly active juvenile oysters that have moved within the switching timing, A shellfish farming method characterized by thinning out the young oysters remaining on the first attachment plate and carrying out a second rearing using the highly active young oysters on the second attachment plate.

2. Inserting the second attachment plate between adjacent first attachment plates; A shellfish farming method as described in claim 1, characterized in that the distance between the first attachment plate and the second attachment plate is a distance that allows the highly active oyster juveniles to move within the switching timing.

3. A shellfish farming method according to claim 1 or 2, characterized in that the switching timing is a timing according to the number of highly active oysters that have moved to the second attachment plate.

4. 3. A shellfish farming method according to claim 1 or 2, characterized in that the second rearing is carried out using the highly active young shellfish with a compound feed.

5. A shellfish farming device for raising shellfish, A plurality of first attachment plates arranged at predetermined intervals and on which the shellfish juveniles are allowed to settle; a first unit including a first support portion for fixing the plurality of first attachment plates; A plurality of second attachment plates are inserted between the first attachment plates and arranged at intervals that allow the juvenile oysters to move from the first attachment plate within the switching timing; A shellfish farming device characterized by comprising a second unit having a second support portion for fixing the plurality of second attachment plates.

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