A device and method for rearing shellfish larvae

Abstract

The application belongs to the technical field of seedling culture, and particularly discloses a device and method for intermediate cultivation of shellfish seedlings. The device is in the shape of a cube, and the cube is connected by a steel structure frame. The steel structure frame comprises a plurality of horizontal supports and a plurality of vertical columns. The interior of the cube is hollow and provided with a plurality of seedling culture layers. Each seedling culture layer comprises a plurality of cultivation units. A plurality of fixed supports perpendicular to the vertical columns are arranged along the length of the vertical columns at equal intervals between adjacent vertical columns. The fixed supports on the four sides of the cube correspond to the seedling culture layers. A plurality of limiting supports are arranged between the fixed supports of each seedling culture layer in a horizontal and vertical staggered manner. The cultivation units are detachably and limitingly embedded between the limiting supports. The device and method for intermediate cultivation of shellfish seedlings are used to fill the blank of the intermediate cultivation of shellfishes such as Sinonovacula constricta and Hyriopsis cumingii, and improve the size and survival rate of the bottom sowing of shellfish seedlings.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of seedling culture, in particular to a device and method for intermediate culture of shellfish seedlings. BACKGROUND

[0002] Sinonovacula constricta is a soft-bodied animal of the family Pharidae and the genus Pharoperna, with a large body and particularly developed foot muscles, and is a very delicious economic shellfish in China. The shell can also be used as a medicine. The shell of Sinonovacula constricta is long, generally 4 to 5 times as long as high, and the two shells are combined in a bamboo tube shape with openings at the front and back. The outer side of the shell body is bare and fleshy. The shell top is located at the front end, the dorsal and ventral edges of the shell are parallel, the surface is smooth without radial ribs, and the growth lines are obvious, sometimes with a light red color band. Sinonovacula constricta lives in the intertidal zone and in the mud and sand of the shallow sea, with a burrowing depth of 30 to 40 cm and a cave inclination. It is a filter-feeding animal that mainly feeds on near-shore benthic diatoms and organic detritus, and is widely distributed along the coast of China. There is currently no method or facility for the intermediate culture of Sinonovacula constricta. After the juvenile shellfish is released from the seedling room, it is usually directly broadcast in the sea area. Since the seedlings are usually only a few millimeters in size, they have poor resistance to enemies and the natural environment, and most of them die after being broadcast, with a very low survival rate.

[0003] Mactra veneriformis is a high-end economic shellfish with a large market demand and a high price. The two shells are small and usually equal in size. The shell surface has serrated teeth at the front end, and the dorsal, ventral, and rear end of the dorsal shell has a secondary shell. The water pipe is very developed, and the thick water pipe cannot be completely retracted into the shell, shaped like an elephant's trunk, hence the name. Mactra veneriformis lives in an area with a water temperature of 0-24℃, a salinity of 26-34, and a water depth of 6-30 meters, and feeds on single-celled algae in seawater, as well as filtering sediment and organic detritus. Mactra veneriformis grows rapidly in the first four years, and as the age increases, the shell growth gradually slows down, but the soft body continues to grow, and the lifespan can reach more than 100 years. Mactra veneriformis has a relatively complete seedling intermediate culture technology and facility in countries where the seedling culture technology is mature. However, China has only recently cracked the artificial seedling culture technology by scientific research institutions, and has not yet carried out large-scale production and promotion. There is currently no method or device for seedling intermediate culture in China. From the results of previous bottom broadcast tests, due to the lack of an intermediate culture process, the survival rate of the seedlings is very low. SUMMARY

[0004] The purpose of the present application is to provide a device and method for intermediate culture of shellfish seedlings, which fills the gap in the intermediate culture of shellfishes such as Sinonovacula constricta and Mactra veneriformis, and improves the size and survival rate of shellfish seedlings in bottom broadcast.

[0005] In order to achieve the above object, the present application provides a device for intermediate cultivation of shellfish seedlings, the device is a whole cube, the cube is connected by a steel structure frame, the steel structure frame comprises a plurality of horizontal supports and a plurality of columns, the inside of the cube is hollow and provided with a plurality of seedling layers, each seedling layer comprises a plurality of cultivation units, a plurality of fixed supports perpendicular to the columns are evenly spaced along the length of the columns between adjacent columns, the fixed supports on the four sides of the cube correspond to form the seedling layers, a plurality of limiting supports are arranged between the fixed supports of each seedling layer in a horizontal and vertical manner, and the cultivation units are detachably and limitingly embedded between the limiting supports.

[0006] Preferably, the plurality of horizontal supports and the plurality of columns are connected to form the cube frame through the connection assembly and the bolts.

[0007] Preferably, a cross support is arranged above the cultivation units of the top seedling layer, and the ends of the cross support are bolted to the horizontal supports.

[0008] Preferably, the ends of the fixed supports are bolted to the corresponding columns, and the horizontal supports, the limiting supports and the fixed supports are all angle steels.

[0009] Preferably, the cultivation units are arranged in a rectangular array on the seedling layers, and gaps are arranged between adjacent cultivation units and adjacent seedling layers.

[0010] Preferably, a bottom support is arranged at the bottom of the column.

[0011] Preferably, hooks are arranged at the top four corners of the steel structure frame, which are used for hoisting the device for intermediate cultivation of shellfish seedlings.

[0012] Preferably, the cultivation units are hard net cages, a substrate beneficial to shellfish sand penetration is arranged in the net cage, and a nylon net cover is arranged on the top of the net cage to prevent enemy invasion.

[0013] The present application also provides a method for intermediate cultivation of shellfish seedlings, which is realized by the device and comprises the following steps.

[0014] Step (1) sea area selection: selecting a sea area with a water depth of 5-15 meters, a seawater flow rate of 0.2-0.75 meters / second, a seawater salinity of more than 25, abundant plankton, a bearing capacity of the seabed of more than 2 tons / square meter and a seabed silt thickness of less than 20 centimeters;

[0015] Step (2) assembly of the intermediate cultivation device: transporting the steel structure frame and the cultivation units of the device for intermediate cultivation of shellfish seedlings to the shore of the sea area for deployment or assembling on a deployment ship, and opening a plurality of cultivation units for juvenile shellfish.

[0016] Step (3) juvenile shellfish selection, select the shell length of 2-10 mm juvenile shellfish, put the juvenile shellfish into the previously laid substrate conducive to the growth of the unit, according to the density of 1 / cm2 The juvenile shellfish is scattered on the substrate conducive to the growth of the shellfish, and immediately after the juvenile shellfish is submerged in the substrate, the growth unit is installed in the steel structure frame of the shellfish seedling intermediate growth device for fixation, and is ready for release;

[0017] Step (4) intermediate growth device release and growth management, the shellfish seedling intermediate growth device containing juvenile shellfish is released into the selected sea area, the adjacent intermediate growth devices are spaced not less than 20 meters, and the growth is observed every week to observe the growth and survival of the seedlings;

[0018] Step (5) after the device is collected, when the juvenile shellfish grows to more than 15 mm in shell length, the shellfish seedlings are collected for later breeding, the substrate conducive to the growth of the shellfish is flushed down together with the seedlings, the substrate conducive to the growth of the shellfish is filtered out for recycling, and the seedlings are carefully collected for counting for bottom planting.

[0019] Preferably, in step (3), the juvenile shellfish is one of Sanguinolaria acuta and Anadonta.

[0020] The advantages and beneficial effects of the above-mentioned intermediate growth device and method for shellfish seedlings are:

[0021] 1. The present application proposes a new mode of intermediate growth of shellfish seedlings in seabed facilities, which fills the gap of intermediate growth of burrowing shellfish in China, and at the same time, the natural growth in the sea area meets the requirements of green ecological aquaculture production, and solves the problems of weak enemy resistance and poor external environment adaptability of burrowing shellfish such as Sanguinolaria acuta and Anadonta in the seedling stage.

[0022] 2. The device adopts a multi-layer cubic frame to disassemble and install the growth unit structure, the multi-layer cubic frame is an assembled steel structure, angle steel is used for positioning and limiting the installation of the growth unit net cage, the cost is low and the operation is convenient, the degree of intensification is high, the net on the top of the net cage protects the seedlings from enemy invasion, and the survival rate is greatly improved, providing healthy seedlings for bottom planting.

[0023] 3. The device forms a breeding space by itself, the size of the device can be flexibly set according to the scale of aquaculture, sea area conditions and other conditions, and the device can be mechanically lifted, released and collected, which saves manpower and material resources and has high efficiency, and meets the development needs of modern fishery.

[0024] The technical solutions of the present application will be further described in detail below with reference to the drawings and examples. DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a schematic view of the overall structure of the intermediate growth device for shellfish seedlings of the present application;

[0026] Figure 2 is a side view of a shell seedling intermediate growing device according to the present application;

[0027] Figure 3 is another side view of a shell seedling intermediate growing device according to the present application;

[0028] Figure 4 is a top view of a shell seedling intermediate growing device according to the present application.

[0029] Reference signs

[0030] 1, transverse support; 2, hook; 3, growing unit; 4, fixed support; 5, limiting support; 6, upright column; 7, bottom support; 8, connecting assembly; 9, cross support. DETAILED DESCRIPTION

[0031] The technical solutions of the present application are further described below by means of the accompanying drawings and examples.

[0032] Unless otherwise defined, technical terms or scientific terms used in the present application shall be understood as having the usual meaning as understood by a person with ordinary skill in the art to which the present application pertains. The terms "first", "second", and similar terms used in the present application do not indicate any order, number, or importance, but are only used to distinguish different components. The terms "include" or "contain" and similar terms mean that the elements or objects listed before the terms encompass the elements or objects listed after the terms and their equivalents, and do not exclude other elements or objects. The terms "connect" or "connected" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right", and the like are only used to indicate relative positional relationships, and when the absolute positions of the described objects change, the relative positional relationships can also change accordingly.

[0033] Example 1

[0034] A shell seedling intermediate growing device, the growing device as a whole is a cube, the cube is connected by a steel structure frame, the steel structure frame includes a plurality of transverse supports 1 and a plurality of upright columns 6, the transverse supports 1 are angle steels. The plurality of transverse supports 1 and the plurality of upright columns 6 are connected by connecting assemblies 8 and bolts to form a cube frame in cooperation with each other. The connecting assemblies 8 include angle connectors and plate connectors, and are used for captive connection. The connecting assemblies 8 belong to the prior art.

[0035] The cuboid is hollowed in the inside and provided with multiple seedling layers. Each seedling layer is provided with multiple seedling units 3. Multiple fixed supports 4 are provided between the adjacent vertical columns 6 and are equidistant along the length direction of the vertical columns 6. The fixed supports 4 on the four sides of the cuboid correspond to the seedling layers. Multiple limiting supports 5 are provided between the fixed supports 4 of each seedling layer and are arranged in a cross pattern. The seedling units 3 are detachably and limitingly embedded between the limiting supports 5.

[0036] Multiple fixed supports 4 are equidistantly provided between the vertical columns 6 on both sides of each side of the cuboid. The ends of the fixed supports 4 are bolted to the corresponding vertical columns 6. Four fixed supports 4 in the same plane enclose a seedling layer. Multiple limiting supports 5 are provided between the four fixed supports 4 and are arranged in a cross pattern. The limiting supports 5 and the fixed supports 4 are angle steels. The limiting supports 5 and the fixed supports 4 form a frame for placing the seedling units 3. The seedling units 3 are detachably embedded in the frame formed by the limiting supports 5 and the fixed supports 4.

[0037] A cross support 9 is provided above the seedling units 3 of the top seedling layer. The ends of the cross support 9 are bolted to the horizontal supports 4. The cross support 9 can improve the stability of the cuboid frame structure.

[0038] The seedling units 3 are arranged in a rectangular array on the seedling layers. Gaps are provided between the adjacent seedling units 3 and the adjacent seedling layers to maintain water permeability. To strengthen the stability of each seedling layer, reinforcing ribs (not shown in the figure) can be provided above the seedling units 3 of the seedling layers below the top seedling layer. The two ends of the reinforcing ribs are bolted to the fixed supports 4.

[0039] The bottom of the vertical column 6 is provided with a bottom support 7 to prevent the accumulation of seabed silt under the device.

[0040] The top four corners of the steel structure frame are provided with lifting hooks 2 for lifting and placing the shell larvae intermediate growing device.

[0041] The seedling unit 3 is a hard net cage. A substrate that is beneficial to the shell larvae to burrow into the sand is placed in the net cage. A nylon mesh is covered on the top of the net cage to prevent the invasion of pests.

[0042] A method for the intermediate growth of shell larvae, comprising the following steps:

[0043] Step (1) selection of sea area: selecting a sea area with a water depth of 5-15 meters, a seawater flow rate of 0.2-0.75 meters per second, a seawater salinity of more than 25, abundant plankton, a seabed bearing capacity of more than 2 tons per square meter, and a seabed silt thickness of less than 20 centimeters;

[0044] Step (2) assembly of the intermediate growing device: transporting the steel structure frame and the seedling units 3 of the shell larvae intermediate growing device to the shore of the sea area where the device is to be placed, or assembling the device on a placing ship. A plurality of seedling units 3 are opened and are ready to be transferred into juvenile shellfish.

[0045] Step (3) juvenile shell selection, select the shell of big bamboo clam or pearl mussel, select the shell length of 2-10mm juvenile shell, put the juvenile shell into the breeding unit 3 which is previously laid with the sand substrate conducive to the shellfish, and the juvenile shell is scattered on the surface of the sand substrate conducive to the shellfish according to the density of 1 per square centimeter, after the juvenile shell sinks into the substrate, immediately install the breeding unit 3 into the steel structure frame of the shellfish seedling intermediate breeding device, and prepare to be put into the sea;

[0046] Step (4) intermediate breeding device putting and breeding management, the shellfish seedling intermediate breeding device with juvenile shell is put into the selected sea area, the adjacent intermediate breeding devices are spaced not less than 20 meters, and the growth and survival of the shellfish seedling are observed by sampling at the fixed point every week during the breeding period;

[0047] Step (5) breeding device collection, when the juvenile shell grows to more than 15mm in shell length, the shellfish seedling is collected for later breeding, the sand substrate conducive to the shellfish is flushed down together with the shellfish seedling, the sand substrate conducive to the shellfish is filtered out for recycling, and the shellfish seedling is carefully collected and counted for bottom planting.

[0048] The above breeding method is used for the intermediate shellfish seedling breeding by taking the big bamboo clam and the pearl mussel seedling as the experimental objects respectively.

[0049] Test sea area: Shicheng Island sea area in Zhuanghe, Dalian, Liaoning Province;

[0050] Test time: from the middle of March to the beginning of August;

[0051] Sea area environment: water depth is 15 meters, seawater flow rate is less than 0.5m / s, seawater salinity is about 30, and water temperature is 5.2-19.8 DEG C. The planting density in each unit cell of the test device is 200,000 particles. The initial size of the pearl mussel seedling is 3.2+ / -0.6mm in shell length, the initial size of the big bamboo clam seedling is 2.5+ / -0.4mm in shell length, the shell length of the big bamboo clam increases to 16.4+ / -1.4mm at the end of the test, and the shell length of the pearl mussel increases to 17.6+ / -2.6mm. The survival rate of the big bamboo clam seedling is 71.5% during the test, and the survival rate of the pearl mussel seedling is 67.2%.

[0052] Device advantage: high survival rate of seedling (the survival rate of the big bamboo clam and the pearl mussel in the bottom planting propagation mode is 1%-5%), easy to concentrate seedling collection and breeding.

[0053] Therefore, the shellfish seedling intermediate breeding device and method are adopted, the intermediate breeding of the shellfish seedling is carried out on the sea by the facility, the intermediate breeding link of the big bamboo clam, the pearl mussel and other shellfish is filled, and the size and survival rate of the bottom planting of the shellfish seedling are improved.

[0054] It should be pointed out finally that the above examples are only used to illustrate the technical solutions of the present application but not to limit it, and although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can still be modified or replaced equivalently, and these modifications or equivalent replacements should not make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A device for intermediate rearing of shellfish larvae, characterized in that: The growing device is cube-shaped, and the cube is made up of a steel frame. The steel frame includes multiple horizontal supports and multiple columns. The cube is hollow inside and has multiple seedling layers. Each seedling layer includes multiple growing units. Multiple fixed supports perpendicular to the columns are evenly spaced along the length of the columns between adjacent columns. The fixed supports on the four sides of the cube correspond to form seedling layers. Several horizontally and vertically intersecting limiting supports are provided between the fixed supports of each seedling layer. The growing units can be detached and embedded into the limiting supports. The ends of the fixed brackets are respectively connected to the corresponding column bolts. The horizontal brackets, limiting brackets, and fixed brackets are all angle steel. The limiting brackets and fixed brackets form a frame for placing the growing unit. The growing unit can be detachably embedded into the frame formed by the limiting brackets and fixed brackets. The growing units are arranged in a rectangular array on the seedling layer, and there are gaps between adjacent growing units and adjacent seedling layers. The breeding unit is a rigid net cage, with a substrate inside that facilitates shellfish burrowing in the sand, and the top of the net cage is covered with nylon netting to prevent predators from attacking. The intermediate rearing method for shellfish larvae includes the following steps: Step (1) Sea area selection: Select a sea area with a water depth of 5-15 meters, a seawater flow velocity of 0.2-0.75 meters / second, a seawater salinity of 25 or higher, abundant plankton, a seabed bearing capacity of 2 tons / square meter or higher, and a seabed silt thickness of less than 20 centimeters. Step (2) Assembly of intermediate rearing device: Transport the steel structure frame and rearing units of the intermediate rearing device for shellfish seedlings to the shore of the release area, or assemble them on the release ship. Several rearing units are opened to prepare for the transfer of juvenile shellfish. Step (3) Selection of juvenile clams: Select juvenile clams with a shell length of 2-10 mm. The juvenile clams are one of the razor clams or geoduck clams. Place the juvenile clams into the breeding unit that has been prepared with a substrate that is conducive to shellfish burrowing. Scatter the juvenile clams on the surface of the substrate at a density of 1 clam per square centimeter. After the juvenile clams have burrowed into the substrate, immediately install the breeding unit into the steel frame of the shellfish seedling intermediate breeding device and fix it in place, ready for release. Step (4) Placement and management of intermediate rearing devices: Place intermediate rearing devices containing juvenile shellfish seedlings into the selected sea area. The distance between adjacent intermediate rearing devices should be no less than 20 meters. During the rearing period, samples should be taken at fixed points every week to observe the growth and survival of the shellfish seedlings. After the juveniles are raised in step (5), the shells are collected. When the shells grow to a length greater than 15 mm, the shellfish seedlings are harvested for later cultivation. The substrate that is conducive to shellfish burrowing is washed down along with the seedlings. The substrate that is conducive to shellfish burrowing is filtered out for recycling. The seedlings are carefully collected and counted for bottom sowing.

2. The intermediate rearing device for shellfish seedlings according to claim 1, characterized in that: Multiple horizontal supports and multiple vertical columns cooperate with each other and are connected by connecting components and bolts to form a cubic frame.

3. The intermediate rearing device for shellfish seedlings according to claim 1, characterized in that: A cross-shaped support is provided above the seedling layer's growing unit, and the ends of the cross-shaped support are bolted to the horizontal support.

4. The intermediate rearing device for shellfish seedlings according to claim 1, characterized in that: The column is equipped with a bottom support.

5. The intermediate rearing device for shellfish seedlings according to claim 1, characterized in that: The steel frame is equipped with hooks at the four corners of its top for the placement and harvesting of shellfish larvae in the intermediate rearing device.

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