JP2007060910A - Method for policulture of seaweed and bivalve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for polyculture of seaweeds and bivalves enhancing utilization efficiency and profitability of sea areas. <P>SOLUTION: The method for polyculture of seaweeds and bivalves comprises culturing seaweeds such as Meristotheca papulosa on the outside of a net basket and simultaneously culturing bivalves such as Chlamys nobilis on the inside of the net basket so that the seaweeds take nutrient salt excreted by the bivalves and thereby the yield of the seaweeds is increased and also seawater pollution is prevented, and so that barnacles adhering to the bivalves are reduced and thereby the bivalves are increased in commercial value. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a mixed culture method for culturing seaweed and bivalves in the sea.

The red seaweed Meristotheca papulosa (Montagne) J. Agardh, which grows in the subtidal zone of the central and southern Pacific coasts of Japan and west coast of Kyushu, is mainly used as a seaweed salad and sashimi. Patent Literature 1 and Patent Literature 2 describe a method for cultivating this quail.

Patent Document 3 describes the creation of a large-scale seaweed bed / underwater forest. In addition to growing kombu, it is stated that scallops and giant mussels are cultivated during the fallow season.
JP 63-216413 A JP2003-81 JP 9-37677 A

Tosakanori is a seaweed with a high commercial value, but the culture methods described in Patent Document 1 and Patent Document 2 are intended only for harvesting Tosakanori, and it is difficult to obtain high profits by such aquaculture method. It is.

Patent Document 3 describes the cultivation of kombu and the cultivation of scallops and giant mussels. The cultivation of scallops and giant mussels is carried out during the fallow period after harvesting the kombu.

An object of the present invention is to provide a method for culturing seaweed and bivalve molluscs with high utilization efficiency and profitability in the sea area.

In order to solve the above-mentioned object, the mixed culture method of the present invention cultivates seaweed outside the net cage and cultures bivalves in the net cage. Seaweed spores are attached to the net cage, and the net cage is suspended in the sea to cultivate the seaweed outside the net cage. For example, sea cucumbers can be cultivated as seaweeds, and bivalve mussels can be cultured.

In the mixed culture method of the present invention, seaweed is cultivated outside the net cage, and bivalve is cultivated in the net cage, so seaweed and bivalve can be harvested in the same sea area, and the use efficiency of the sea area is high and profitability is also high. improves. Since the bivalve waste is adsorbed as seaweed nutrient, it has the effect of preventing seawater contamination and increasing the yield of seaweed.

The best mode for carrying out the present invention will be described. FIG. 1 is a front view showing a mixed culture facility. In the mixed culture method of the present invention, the net cage 1 is used. Put the juvenile shellfish into this net cage 1 and hang it in the sea to cultivate the bivalve 2.

Further, seaweed 3 is cultivated outside the net cage 1. For example, when seaweed spores are attached to the net cage 1 and the net cage 1 is suspended in the sea, the seaweed 3 grows outside the net cage 1.

Thus, it is important to culture the bivalve 2 and the seaweed 3 with the same net cage 1. The seaweed 3 surrounds the bivalve 2, and the excrement of the bivalve 2 is absorbed by the seaweed 3. The growth of seaweed 3 is promoted by absorbing bivalve excrement as nutrients. Moreover, since the outflow of bivalve excrement into seawater is reduced, contamination of the sea area is prevented.

Next, examples of the present invention will be described. This is an example of mixed aquaculture of Tokakanori and Mimachlamys nobilis in Murote Bay, Ainan-cho, Uwa-gun, Ehime Prefecture.

As the net cage 1, a hanging bivalve cultured net cage (length 30 cm × width 30 cm, height 20 cm, mesh 0.7 cm × 0.7 cm, quadrangular pyramid type made from Cremona) was used. This type of netting is used in the cultivation of giant snails and pearls and is readily available.

The adhesion of spores to the net 1 will be described. FIG. 2 is an explanatory diagram showing the situation of spore adhesion. Perform in June. The spore of Tosakanori was made to adhere to the net cage 1 by suspending the net cage 1 and the mature leaf body 5 of Tokakanori in the water tank 4 and slowly flowing seawater pumped up by a pump.

FIG. 3 is a perspective view showing an aquaculture cage. This aquaculture cage 6 is the same as that used in pearl culture. The net cage 1 to which spores were attached was tied to a rope made of Cremona, and 9 cages were suspended from the aquaculture cage 6 installed in the bay at a depth of 2 m, 5 m, and 8 m, respectively.

In September, put a giant clam larvae into this net cage 1. After measuring the wet weight of the mussel clams, attaching individual identification tags, 15 individuals were put into the net cage 1 respectively. Thus, the net cage 1 containing the giant clam clam was returned to its original position and continued to be cultured in the sea until April of the following year.

Moreover, as Comparative Example 1, a net cage that had spore attached but no giant mussel was also installed in the sea. In addition, as Comparative Example 2, a cypress shell with no spore attached was placed in the sea.

The net cage of Comparative Example 2 is pulled up to the sea level every month, and after removing the seaweed adhering to the net cage, it is returned to the sea. On the other hand, the net cages of the present example and comparative example 1 are also lifted to the sea surface every month, but the seaweed is not removed and returned to the sea as it is.

While carrying out the above treatment, the culture was continued until April 25, 2004, and the reeds were pulled up to collect Tosakanori and Hiugi Guy. The number of spinach we collected was measured for the number of strains and dry weight, and for the giant clam, wet weight and barnacles attached to the shell were measured. The specific growth rate per day (r = ln (Δw / Δt)) was calculated from the wet weight before and after the cultivation of the snail. These measurement items were compared in Example, Comparative Example 1 and Comparative Example 2.

FIG. 4 is a graph showing the total dry weight of Tokakanori, and FIG. 5 is a graph showing the average number of copies of Tokakanori. The data of this example and Comparative Example 1 are displayed respectively.

Compared to Comparative Example 1 (n = 15), this example (n = 14) significantly and significantly increased the dry weight of Tokasori. There was no difference in the crop yield between the depths.

The number of strains was significantly and significantly increased in this example (n = 14) as compared to Comparative Example 1 (n = 15). Regarding the number of strains, there was also a difference between the depths, and the number of Tosakanori strains increased significantly as the water depth increased.

FIG. 6 is a graph showing the specific growth rate per day of the giant snail. The data of the present Example and the comparative example 2 are displayed. Although a slightly higher tendency was observed in this example than in Comparative Example 2, no statistically significant difference was observed. However, there was a significant difference between the depths, and the growth rate of the mussel increased significantly with increasing culture depth.

FIG. 7 is a graph showing the number of barnacles attached to the snail. The data of the present Example and the comparative example 2 are displayed. The number of barnacles adhering was significantly less in this example than in Comparative Example 2. There was no difference between the depths.

Until now, when shellfish were cultivated, the attachment of seaweed to the aquaculture net was considered to have a negative effect on the growth of the species to be cultured. However, as described above, no difference was found in the growth rate of the cypress cultivated with Tokakanori compared to the cypress cultivated with shellfish alone.

On the other hand, the number of barnacles adhering to the snail was less in the mixed cultivated snail than in the snail cultivated alone. Adherent animals such as barnacles and tubeworms not only stress the snails, but also reduce their commercial value, so removing them requires considerable time and effort. Therefore, by reducing the number of barnacles, labor costs can be reduced and the product value can be increased.

Moreover, the yield of Tosakanori increased by mixed culture rather than by seaweed alone. That is, this invention has the effect of increasing the production amount of Tosakanori by carrying out mixed culture with a bivalve. The present invention enables highly productive aquaculture by making effective use of limited space and marine resources (suspended organic matter and nutrients).

Natural purification using bivalves is a method that promotes the purification of water systems by raising bivalves grown on suspended organic matter to the land. However, the conventional purification method has a negative effect that the nutrient salt eluted from the bivalve promotes primary production and increases suspended organic matter, so it is difficult to say that the purification efficiency is high. In this example, Tosakanori mixed and cultured with bivalves produced higher yields than those cultured with seaweed alone. From this result, it was confirmed that the Tosakanori can absorb the nutrient salt eluted from the bivalve by mixing and cultivating Tosakanori with the bivalve.

Further, the net cage 1 and the aquaculture cage 6 used in the present embodiment are widely used for pearl farming and the like, and a lot of new equipment investment is unnecessary for many fishermen.

INDUSTRIAL APPLICABILITY The present invention can be used as a seaweed cultivation method with a large yield and can be used as a bivalve cultivation method that can produce bivalves with high commercial value. And it can utilize as a highly profitable mixed culture method which can harvest both seaweed and bivalve. It is possible to prevent the seawater from being contaminated by nutrients that are excreted from the bivalve molluscs, and it can be implemented as an environmentally friendly fishery industry.

It is a front view which shows the facility of mixed culture. It is explanatory drawing which shows the condition of spore adhesion. It is a perspective view which shows the cage | basket for aquaculture. It is a graph which shows the total dry weight of Tosakanori. It is a graph which shows the average number of copies of Tosakanori. It is a graph which shows the specific growth rate per day of a giant snail. It is a graph which shows the number of the barnacles adhering to the giant clam.

Explanation of symbols

1. Net cage 2. 2. bivalves Seaweed 4. 4. Water tank Tosakanori mature leaves Aquaculture

Claims (3)

A mixed culture method in which seaweed is cultivated outside the net cage and bivalves are cultivated in the net cage. A mixed aquaculture method in which spores of seaweed are attached to the net cage, the net cage is suspended in the sea, and the seaweed is cultured outside the net cage, and the bivalve is cultivated in the net cage. A mixed aquaculture method in which spores of Tokakanori are attached to the net cage, the net cage is hung in the sea and the Tokakanori is cultivated outside the net cage, and a giant mussel is cultivated in the net cage.

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