CN113940299A

CN113940299A - Method for restoring estuary sea area fishery resources

Info

Publication number: CN113940299A
Application number: CN202111173374.XA
Authority: CN
Inventors: 李桂峰; 易华东; 曾泽雨; 毕胜; 赖瀚; 李海洋
Original assignee: Sun Yat Sen University
Current assignee: Sun Yat Sen University
Priority date: 2021-10-08
Filing date: 2021-10-08
Publication date: 2022-01-18

Abstract

The invention provides a method for restoring fishery resources in estuary sea areas. The method comprises the steps of arranging a plurality of floating raft type hanging rows in the sea area to be repaired, connecting a plurality of ropes below the floating raft type hanging rows, and stringing oyster shells or oyster seedlings on the ropes. On one hand, the method can provide a spatial heterogeneous three-dimensional biological structure for the sea area, and provide habitat and shelter for a plurality of important benthonic invertebrates, fishes and planktonic crustaceans, so as to improve the ecological diversity of the sea area and restore the fishery resource amount of the sea area; on the other hand, the oyster cultivation can be carried out, the oyster cultivation method has the advantages of protection and utilization, and the practicability is high.

Description

Method for restoring estuary sea area fishery resources

Technical Field

The invention belongs to the technical field of fishery resource restoration. And more particularly, to a method for restoring fishery resources in estuary sea areas.

Background

The oyster is a marine benthonic animal and grows in a temperate river mouth water area where salt water and fresh water are intersected. The fresh oysters can be gathered and grown in large quantities to form large-area oyster reefs. The oyster reef is used as a special marine habitat and has very important functions in the aspects of biodiversity protection, water purification, ecological system structure maintenance, fishery production promotion and the like. In many estuary ecosystems, oyster reefs have very important ecological functions, mainly including 3 aspects: (1) a water body purification function; as filter feeding benthonic animals, the oysters can effectively reduce suspended particles, phytoplankton and debris in estuary water, and can accumulate a large amount of heavy metal ions in soft tissues of the oysters, so that the transparency of the water is improved, and the primary productivity of an aquatic ecosystem is increased; (2) habitat function; the oyster reef is a marine habitat with high biodiversity, and provides a good habitat and a good food intake place for a plurality of benthonic animals and fishes; (3) an energy coupling function; the oysters can input a large amount of particles in the water body to the surface of the sediment to support the production of the benthic debris. In addition, the oyster reefs also have very important functions in the aspects of stabilizing coastlines and bottom materials, promoting nutrient substance circulation and the like.

In recent decades, the problem of estuary eutrophication has become more serious, and most researches suggest that the eutrophication is mainly caused by the increase of the nitrogen and phosphorus concentration of the water body. However, there is also evidence that estuary eutrophication problems are associated with a reduction in biomass of bivalves (mainly oysters) (upgoing effect). Therefore, the recovery of the number of oyster species is an important measure for controlling the eutrophication of the estuary. In addition, as bivalve mollusks, oysters can accumulate high-concentration pollutants in soft tissues of the oysters, particularly have high biological enrichment capacity on heavy metals, have a biological enrichment coefficient of 102-104 generally, and have an obvious effect on reducing heavy metal pollution of water bodies. With the need of frequent human activities and economic development, a plurality of oyster reef systems along the sea are damaged, the habitat value, the productivity and the bearing capacity of fishes and fishery are reduced, and measures for repairing oyster reefs and fishery resources are urgently needed.

The existing repairing method is mainly used for artificially constructing the oyster reefs with fixed positions in the offshore area, but the method is limited by natural conditions and has high construction cost. For example, chinese patent CN104686418A discloses an implementation method of an artificial reef construction project for repairing oyster reefs, which uses hydraulic buildings (hollow bricks and culverts) and waste oyster shells (packaged for processing) as reefs, and by a series of implementation methods of construction and placement, oyster seedlings in water are directly attached to the artificial reefs, so as to achieve the goals of cultivating young seedlings with waste, cultivating live seedlings with dead shells, proliferating the number of oyster populations, amplifying the area of living oyster reefs, and repairing natural oyster reefs and recovering associated ecosystems. In addition, most of the existing oyster cultivation rows are fixed and piled and cannot move, and because only a certain sea area exists for a long time, the oyster growth effect is not good relatively, and good economic value cannot be obtained. While the chinese patent CN104585099A discloses a movable oyster cultivation method, the main purpose is to prevent oysters from being held back; the oysters are attached to the hanging strings for cultivation and are changed into a movable cultivation mode, so that the oysters can be transferred to an environment with proper seawater temperature and salinity for cultivation, and the death rate caused by incapability of discharging sperm and eggs in the oyster cultivation process is reduced. Therefore, the oyster is hung on a movable carrier, so that the aim of selecting a proper sea area at any time to move is fulfilled, and the problem that sea area fishery resources decline cannot be solved.

Disclosure of Invention

The invention aims to overcome the defects and shortcomings of the prior art and provide a method for restoring estuary sea fishery resources.

The above purpose of the invention is realized by the following technical scheme:

the invention provides a method for restoring fishery resources in estuary sea area by using a floating raft type hanging raft and oyster seedlings or oyster shells. The repairing method comprises the steps of arranging a floating raft type hanging row in the sea area to be repaired, connecting a plurality of ropes below the floating raft type hanging row, and stringing oyster shells or oyster seedlings on the ropes. On one hand, the method can provide a spatial heterogeneity three-dimensional biological structure (comprising a buoyant raft type hanging raft, a three-dimensional biological structure formed by oysters or oyster shells adhered to ropes and an adhesion structure among the oyster shells) for the sea area to be repaired, and provides habitats and shelters for a plurality of important benthonic invertebrates, fishes and planktonic crustaceans, so as to improve the ecological diversity of the sea area and repair the fishery resource quantity of the sea area; on the other hand, the oyster cultivation can be carried out, the oyster cultivation method has the advantages of protection and utilization, and the practicability is high.

The invention provides a method for restoring fishery resources in estuary sea areas, which is characterized in that a plurality of floating raft type hanging rows are distributed in the sea areas to be restored; a plurality of ropes are connected below the floating raft type hanging row, and oyster shells or oyster seedlings are connected on the ropes.

Specifically, the number of ropes in every 1 square meter sea area is 20-30, and the distance standard of all the ropes after arrangement is 20-50 cm.

Specifically, the rope begins to set up the node at 20 ~ 30cm department apart from the surface of water for connect the oyster cluster, the node interval is 12 ~ 15cm, and 5 ~ 10 oyster shells or oyster seedling are connected to every node.

Specifically, each rope is provided with 10-12 nodes.

Specifically, the standard of arrangement of the floating raft type hanging row is as follows: 35-50 floating raft type hanging rows are arranged in the sea area of every 2 hectares, and the distance between the floating raft type hanging rows is 1-50 m.

Specifically, when the raft type hanging rows are arranged, every 7-10 raft type hanging rows are connected into a group by ropes, and the groups are arranged in parallel.

Specifically, the distance between the floating raft type hanging rows in the same group is 1-1.5 m, and the distance between the groups is 6-50 m.

Specifically, 350-750 ropes are connected to the lower portion of each floating raft type hanging row, and the distance between the ropes is 10-30 cm.

Specifically, the floating raft type hanging row is a rectangle with the length of 5m and the width of 3 m.

Specifically, the salinity range of the sea area to be repaired is 10% -25%.

More specifically, the salinity range of the sea area to be repaired is 10% -25%, the wind wave is small, the water temperature changes stably all the year round, the water quality is stable, and no industrial pollution is caused.

Preferably, before the oyster seedlings are connected to the ropes, punctuations are required to be set in the sea area to be repaired, the oyster seedlings are subjected to trial culture, and then the oyster seedlings are subjected to batch seedling separation after the oyster seedlings are determined to be suitable for the application.

When the floating raft type hanging raft is used for repairing estuary sea fishery resources, if oyster seedlings are used, the raft type hanging raft can be moved to a proper sea area according to seasons, on one hand, fishery resource repair is carried out, on the other hand, the growth effect of oysters can be better, stable oyster resources are provided, and higher economic value is obtained. After the oysters are cultivated, continuously transplanting oyster seedlings for cultivation, and repeating the steps.

The invention also provides a floating raft type hanging raft which is a rectangular bamboo raft consisting of bamboo poles, wherein the bottom of the bamboo raft is provided with a buoyancy device, and the buoyancy device consists of a hollow plastic barrel.

The manufacturing process of the floating raft type hanging row is as follows:

s1, bundling 3 bamboo poles with the length of 5m into a bundle, manufacturing 5 bundles, arranging the 5 bundles at equal intervals, and fixing a bamboo pole with the length of 3m at each end of the bamboo pole bundle by using iron wires and ropes to form a rectangular frame;

s2, fixing bamboo poles with the length of 3m in the rectangular frame at intervals of 20-30 cm by taking the short side of the rectangular frame constructed in the step S1 as a boundary, wherein the bamboo poles are used for binding ropes of oyster strings;

and S3, after the bamboo poles are fixed, arranging a buoyancy device at the bottom of the manufactured bamboo raft.

Specifically, the bottom of each hanging row is provided with 20 hollow plastic drums, 5 hollow plastic drums are arranged in one group, the groups are arranged in parallel, and the distance between the plastic drums is 20-50 cm.

Specifically, the hollow plastic barrel has the outer diameter of 360mm, the caliber of 320mm, the height of 605mm, the volume of 60L and the weight of 3.1 kg.

The invention has the following beneficial effects:

the invention provides a method for restoring fishery resources in estuary sea area by using a floating raft type hanging raft and oyster seedlings or oyster shells. On one hand, the floating raft type hanging raft and the oyster seedlings or oyster shells can provide a three-dimensional biological structure with spatial heterogeneity for the sea area to be repaired, and provide habitats and refuges for a plurality of important benthonic invertebrates, fishes and planktonic crustaceans, so that the ecological diversity of the sea area is improved, and the fishery resource quantity of the sea area is repaired; on the other hand, the oyster cultivation can be carried out, and the oyster cultivation method has the advantages of protection and utilization. In addition, the oysters can also greatly reduce the deposition of phytoplankton and granular organic carbon, and play a role in purifying water quality.

Drawings

Fig. 1 shows a raft-type hanger made by the method of the present invention.

FIG. 2 shows the results of the study of the diversity of fishes at a sampling site when the method of the present invention is used to restore estuary waters with oyster shells.

FIG. 3 is the results of a study of the diversity of the sampled fish species shown in FIG. 2 after 2 months.

FIG. 4 shows the results of the study on the diversity of fishes at a sampling site when the estuary sea area is restored with oyster shells by the method of the present invention.

Detailed Description

The invention is further described with reference to the drawings and the following detailed description, which are not intended to limit the invention in any way. Reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated.

Unless otherwise indicated, reagents and materials used in the following examples are commercially available.

Example 1 remediation of estuary sea fishery resources

1. Selecting estuary waters to be restored

The salinity range is preferably 10% -25%, the sea area has small wind wave, stable water temperature change all the year round, stable water quality and no industrial pollution.

2. Manufacturing floating raft type hanging row

The buoyant raft type hanging row manufactured by the method is shown in figure 1. The floating raft type hanging row takes bamboo poles as main frames, and each hanging row is 5 meters long and 3 meters wide. When in manufacturing, 3 bamboo poles with the length of 5m are firstly combined into 1 bundle of long sides for manufacturing the hanging row, 5 bundles are manufactured in total, and each bundle is arranged at intervals of about 70 cm; taking 2 thicker bamboo poles with the length of 3m, and fixing the bamboo poles at two sections of the bamboo pole bundle by using iron wires and ropes respectively to form a rectangular frame; the rectangular frame is internally fixed by 25 thin bamboo poles with the length of 3m, and the short sides of the rectangular frame are used as boundaries, and one bamboo pole is fixed at two ends of the rectangular frame at intervals of 20-30 cm to form a floating raft type hanging row. In addition, ropes with the length of 1.5 meters are tied on the manufactured hanging row bamboo poles at intervals of 10-15 cm, and nodes are arranged on each rope at equal intervals from 20-30 cm under water and used for bonding oyster strings; every node interval 12 ~ 15cm, every node can glue 5 ~ 10 oyster seedlings or oyster shell, and a rope can set up 10 ~ 12 nodes.

In order to make the made hanging row float on the sea surface, a buoyancy device is also needed. A buoyancy device is arranged between two bamboo pole bundles with the length of about 5 meters in the oyster row, and 4 buoyancy devices are arranged in each oyster row. The buoyancy device consists of 5 hollow plastic cylinders which are arranged in a line at equal intervals, wherein the outer diameter of each hollow plastic cylinder is 360mm, the caliber of each hollow plastic cylinder is 320mm, the height of each hollow plastic cylinder is 605mm, the volume of each hollow plastic cylinder is 60L, and the weight of each hollow plastic cylinder is 3.1 kg.

3. Floating raft type hanging row

Firstly, the manufactured unit floating raft type hanging rows are connected in series by thick ropes to form a group, and every 7-10 floating raft type hanging rows are formed into a group and are spaced by 1-1.5 m. And forming a floating raft type hanging row area by using floating raft type hanging row groups, wherein the distance between every two hanging rows in the sea area needs 6-50 meters, and at least 5 floating raft type hanging rows are included in every 2 hectare of sea area.

4. Restoration of estuary sea area fishery resources

And manufacturing a plurality of groups of hanging rows in the selected estuary sea area to be repaired according to the manufacturing method of the floating raft type hanging row.

If the oyster seedlings are selected for restoration, the oyster seedlings need to be temporarily cultured in a bay, and when the oyster seedlings are not easy to fall off, the oyster seedlings can be cultured in the sea by separating the oyster seedlings. And 4-5 days before separating the oyster seedlings, arranging a plurality of mark points in the sea area to be repaired, taking a plurality of strings of oyster seedlings for trial culture, and judging whether the oyster seedlings can adapt. After the oyster string is determined to be adaptable, the oyster string is hung on a floating raft type hanging row for cultivation. During the cultivation of the oysters, the hanging raft can be moved to a proper sea area according to seasonal sea area salinity environment changes. After the oysters are bred to reach the commodity specification and collected, the oyster seedlings are continuously transplanted for breeding, and the fishery resources can be repaired by circulating and repeating.

If the oyster shells are selected for repairing, the oyster shells are hung below the floating raft type hanging row and moved to the sea area to be repaired.

Example 2 fishery resource repair investigation result combining hanging raft with oyster seedling

By using the method of the embodiment 1, fishery resource restoration is performed in the estuary sea area of Taishan city in Guangdong province by using the floating raft type hanging raft combined with oyster seedlings, fishery resources in a control area (no floating raft hanging oyster rows) and a floating raft hanging oyster row area are respectively investigated, and the investigation is performed again after 2 months.

According to the invention, water layers of water areas of a control area (sampling points are A0) and a culture area (sampling points are A1 and A2) are sampled by catching modes such as a purse net, a trawl, a sprinkling net and a fishing cage, parameters such as fish species composition, full length, body length and weight are counted, and the ecological types of fishes are divided. And diversity studies were performed using the Margalef abundance index (D), the Shannon-Wiener diversity index (H ') and the Pielou uniformity index (J').

Wherein, the calculation formula of the Shannon-Wiener diversity index is as follows:

wherein S is the total number of sample types in the collected samples.

The Pielou uniformity index is used to calculate the uniformity of distribution of different fish species in a colony, indicating the degree to which the number (or biomass) distribution of each species is uniform across the colony. When the Pielou uniformity index is calculated, a Shannon-Wiener diversity index H 'needs to be measured firstly, then a theoretical maximum value Hmax is calculated, and the Pielou uniformity index is obtained by solving the ratio of the H' to the Hmax. The calculation formula is as follows:

wherein J is the uniformity, H' is the Shannon-Wiener diversity index, S is the total number of fish species in the sample, and Hmax is the maximum value of the Shannon-Wiener diversity index.

The Margalef abundance index measures the number of species present in a population and analyzes the abundance of species in the population based on the number of species present. The Margalef abundance index calculation formula is as follows:

wherein S is the total number of sample types in the sample collected by the fishing gear, and N is the total number of biological individuals in the sample.

The method for investigation and sampling is mainly carried out according to methods of Zhang Min, Shi Zhi Hui, 1991 and Marine survey Specification (GB/T12763.6-2007). The fish identification and the ecological type division are mainly based on Chinese annals, Guangdong freshwater fish annals, Zhujiang fish annals, south sea fish annals, FishBase databases and the like. The occurrence of synonyms and synonyms is mainly subject to the Chinese animal record and the FishBase database.

The fish abundance of the sampling points repaired with oyster fries is shown in table 1.

TABLE 1 sampling points Fish abundance table

The fish bio-scale for each sampling point repaired using oyster shell seedlings is shown in table 2.

TABLE 2 sampling points Fish Biometrics

The results of the study on the diversity of fishes at each sampling site repaired with oyster fries are shown in FIG. 2. The fish diversity index reflects the abundance and uniformity of species, is a numerical value used for calculating the diversity of a community, the size of a simple number obtained by calculation represents the diversity of the community, the stability of the community can be analyzed according to the diversity degree, and the higher the diversity index value is, the more the variety of organisms in the area is, the closer the relationship among the organisms is.

As shown in FIG. 2, the Shannon diversity index (A1:1.886, A2:1.774) and the Margalef's species abundance index (A1:2.552, A2:2.659) of the area where the floating rafts suspended-cultured oysters are arranged are both greater than the Shannon diversity index (A0:1.715) and the Margalef's species abundance index (A0:0.6083) of the control area. The Pielou's uniformity index (A1:0.8193, A2:0.7399) was also significantly greater in the raft-fed oyster row area than in the control zone (A0: 0.2768). The results show that the biological community types of the floating raft suspended culture oyster row area are more abundant, the number distribution of all the species is more uniform, and the organisms of the community are more diverse.

The fish abundance of the same sampling point after 2 months of the interval is shown in table 3.

TABLE 3 sampling point Fish abundance table

The fish bio-scale for the same sampling point after 2 months interval is shown in table 4.

TABLE 4 sampling point Fish Biometrics

The results of the diversity study on fish at the same sampling point after 2 months are shown in FIG. 3. As shown in FIG. 3, the Shannon diversity index (A1:1.979, A2:2.201) and the Margalef's variety abundance index (A1:3.21, A2:3.348) of the raft hanging oyster row area are both greater than those of the control area (A0:1.88) and the Margalef's variety abundance index (A0: 2.519). The result shows that the constructed floating raft suspended culture oyster raft area has richer biological community types, more uniform distribution of the number of species and more diversity of community organisms, and the method for repairing river mouth fishery resources by using the floating raft suspended culture oyster raft can really improve fishery resources in sea areas.

The related results show that the oyster reef is a marine habitat with high biodiversity, has important ecological functions and service values, and provides good inhabitation and ingestion places for a plurality of benthonic animals and fishes. The Shannon diversity index mean value (2.942) of fishery resource survey in the floating raft suspended-culture oyster row area repaired by oyster seedlings in different periods (2 months at intervals) is higher than that of the contrast area (2.117), which shows that the biological community type of the floating raft suspended-culture oyster row area is richer, the number distribution of various species is more uniform, and the biological diversity of the community is better.

Example 3 Fishery resource repair survey result combining hanging row with oyster Shell

By using the method described in example 1, fishery resources were restored in the estuary sea area of Taishan city, Guangdong province by using the floating raft type suspended raft combined with oyster shells, and fishery resources in the control area (no floating raft suspended oyster row) and the floating raft suspended oyster row area (only oyster shell, no live oyster) were investigated respectively.

The investigation method and calculation method were the same as in example 2.

The fish abundance of the sampling points repaired with oyster shells is shown in table 5.

TABLE 5 sampling point Fish abundance table

The fish biomass scale of the sampling points where oyster shell was used for repair is shown in table 6.

TABLE 6 sampling point Fish Biometrics

The results of the study on the diversity of fishes at the sampling site where oyster shells were used for restoration are shown in FIG. 4. As can be seen from FIG. 4, the Shannon diversity index (A1:2.381, A2:1.931), Pielou uniformity index (A1:0.687, A2:0.5927) and Margalef's abundance index (A1:4.259, A2:3.545) of the oyster row region formed by combining oyster shells with the floating raft type hanging row are all greater than those of the control region (Shannon diversity index (A0:1.727), Pielou uniformity index (A0:0.5673) and Margalef's abundance index (A0: 3.545)). The results show that the oyster row area formed by combining oyster shells with hanging rows has richer variety of biological communities, the number distribution of all species is more uniform, and the biological diversity of the communities is better, so that the method for restoring the estuary sea fishery resources can really improve the fishery resources of the restored sea area.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.

Claims

1. A method for restoring fishery resources in estuary sea areas is characterized in that a plurality of floating raft type hanging rows are distributed in the sea areas to be restored; a plurality of ropes are connected below the floating raft type hanging row, and oyster shells or oyster seedlings are connected on the ropes.

2. The method according to claim 1, wherein the number of the ropes is 20-30 per 1 square meter sea area, and the interval between all the ropes is 20-50 cm after arrangement.

3. The method according to claim 1, wherein the rope is provided with nodes at a distance of 20-30 cm from the water surface for connecting the oyster strings, the distance between the nodes is 12-15 cm, and each node is connected with 5-10 oyster shells or oyster seedlings.

4. A method according to claim 3, wherein 10 to 12 nodes are provided per rope.

5. The method according to claim 1, wherein the salinity of the sea area to be repaired is in the range of 10% to 25%.

6. The method of claim 1, wherein before the oyster fries are attached to the rope, the oyster fries are tried to be cultured in the sea area to be repaired by setting a mark point, and then the oyster fries are divided into batches after the oyster fries are determined to be adaptable.

7. The method of claim 1, wherein the raft-type rows are arranged according to the following criteria: 35-50 floating raft type hanging rows are arranged in the sea area of every 2 hectares, and the distance between the floating raft type hanging rows is 1-50 m.

8. The method as claimed in claim 7, wherein the raft rows are arranged in groups of 7-10 raft rows, and the groups are arranged in parallel.

9. The method of claim 8, wherein the raft rows of the same group are spaced apart by 1 to 1.5m and the group-to-group spacing is 6 to 50 m.

10. The method of claim 9, wherein 350-750 ropes are connected under each raft-type hanger row, and the distance between the ropes is 10-30 cm.