CATDOLL : CATDOLL: How about raising fish in the countryside now? Which one is more economically profitable, silver carp or bighead carp?

First of all, it is definitely possible to raise fish in the countryside. As for which one has higher economic benefits, silver carp or bighead carp, let's analyze it below:

The difference between silver carp and bighead carp

1. The heads of silver carp and bighead carp are relatively large, especially the head of silver carp, which occupies 1/2 or even more of the entire body. Therefore, silver carp is also called "fathead fish" and is famous for its meaty head.

2. Because they both live in the upper layer of water, fishermen say that the fishing methods for silver carp and bighead carp are different, using the floating fishing method. The difference between them is that the distance of the fish hook from the water surface is a little different, 40 cm deep for silver carp and 60 cm deep for bighead carp. In addition, acid bait is used for silver carp and smelly bait is used for bighead carp.

3. Silver carp, with a large head and light black spots on its body. Bighead carp, with a small head and all white scales, without black spots.

There is a legend that goes like this: In the past, a family was preparing a banquet, and the servants prepared a dish of silver carp. The host only saw the head but not the body, and felt that it was not worthy of being served in a formal banquet, so he took the dish away and told the servants: "You can take it and eat it." In the past, servants were often called "mediocre people", so this fish was also called "silly carp", which means a dish that cannot be served "on the table".

According to realistic understanding, silver carp is slow and docile, just like humans who are mediocre and idle, so it is named mediocre fish (bighead carp).

4. Food habits of silver carp and bighead carp

Bighead carp mainly feeds on zooplankton, and also on phytoplankton. According to the research of Professor Ni Dashu, the average ratio of zooplankton to phytoplankton in the diet of bighead carp is 1:4.5. Phytoplankton is dominant in quantity, but its biomass is far less than that of zooplankton. On average, one zooplankton is 10 times larger than one phytoplankton or more. Therefore, from the analysis of the diet of bighead carp, the occurrence rate of phytoplankton is not low, but zooplankton still plays a major role in nutrition.

Silver carp is an upper-layer fish with an aggressive temperament and a habit of jumping (sometimes even jumping out of the water), so fish farmers often predict the growth and yield of silver carp based on its "jumping" behavior.

Most of the current pond aquaculture is mainly based on raising edible fish (such as grass carp, carp, crucian carp, etc.). Due to the large amount of food they eat, they often excrete a lot of feces, which will lead to excessive fertilizer in the water quality, easily causing blue algae or serious eutrophication in the water, making it unsuitable for survival.

We all know that bighead carp mainly feeds on zooplankton, while silver carp mainly feeds on phytoplankton. We can use the food chain principle of these fish co-breeding. The feces discharged by grazing fish such as grass carp, bream, black carp, carp, and crucian carp are a good source of fertilizer for fertilizing water quality and breeding plankton. With this fertilizer source, phytoplankton will breed, and silver carp feeds on phytoplankton. For this reason, filter-feeding silver carp must be co-cultured in the pond, followed by bighead carp, in order to purify the water quality and achieve mutual benefit.

But the reality is that many people disdain silver carp for its low value and refuse to raise it together, not knowing that silver carp is the nemesis of blue-green algae and must be raised together with it, otherwise the annual blue-green algae outbreak will be a real headache.

In fact, there is no cost or very low cost to raise silver carp and bighead carp together with other fish. Therefore, the profit of silver carp and bighead carp is very high. Don't think that silver carp is despised because of its low selling price. This is a wrong misunderstanding.

5. Mixed ratio of silver carp and bighead carp

From the perspective of the food chain, phytoplankton uses solar energy to carry out photosynthesis. Since fertile water first reproduces phytoplankton, and zooplankton mostly feed on phytoplankton, the food of bighead carp is converted from the leftover food of silver carp. Therefore, there is a proportional relationship in the stocking ratio of bighead carp and silver carp.

There is a saying among fish farmers in some places: "One grass carp, three bighead carp and nine silver carp". The ratio of three to nine is 1 to 3, which means that one bighead carp is needed to match three silver carp.

Why is this so?

Because the phytoplankton in the water always reproduces first, and the number is large and the variety is diverse. However, it is impossible for silver carp to eat all the phytoplankton in the water, so some of them are used as food by zooplankton and thus become food for bighead carp.

From the perspective of the food chain, if more silver carp are released, the amount of phytoplankton in the water will inevitably decrease, and the food for zooplankton will decrease accordingly, providing less food for bighead carp. However, this does not mean that all silver carp should be released to eat up all the phytoplankton in the water. This is unscientific and unrealistic.

In order to comprehensively utilize water bodies and carry out three-dimensional production (silver carp lives in the upper layer of water, while bighead carp lives in the middle layer of water), and given the high value of bighead carp, appropriately controlling the stocking amount of silver carp and leaving enough food for bighead carp is one of the measures to increase the yield per unit area.

Furthermore, silver carp may not like to eat some phytoplankton, but these phytoplankton that silver carp do not like to eat become food for zooplankton, providing a food basis for bighead carp. Therefore, in order to tap the productivity of water bodies, both should be equally important, and the core issue is the issue of proportion.

In summary, the number of phytoplankton in the water mostly exceeds the number of zooplankton, so it is better to put more silver carp and less bighead carp. Don't think that bighead carp is more valuable, so you only raise silver carp but not bighead carp, or put more silver carp and less bighead carp, which is also inappropriate.

6. Mainly or exclusively raising silver carp

Unless you have special expertise, it is possible to mainly raise or specialize in silver carp, but this is not possible according to the current level of breeding technology. It is hoped that with the improvement of scientific fish farming technology in the future, it will be possible.

Therefore, how to increase the stocking ratio and yield of bighead carp has become a technical problem that needs to be solved urgently in aquaculture production.

With the application of bio-organic fertilizers and biological agents in aquaculture, the algae composition of water bodies has also undergone fundamental changes, creating certain conditions for improving the production ratio of bighead carp.

The zooplankton that bighead carp can eat are large, nutritious and easily digestible. After using biological organic fertilizers and biological agents, diatoms, dinoflagellates and cryptoalgae may become dominant populations, providing a correspondingly abundant supply of natural bait for zooplankton. Of course, the biomass of zooplankton is also very high, providing a food basis for bighead carp to become the main farmed fish.

According to many years of production practice, in the stocking structure of silver carp and bighead carp, if the proportion of bighead carp is less than 20% or greater than 80%, the growth rate of bighead carp is faster. When the stocking ratio of silver carp is between 20% and 80%, the growth rate of bighead carp will be inhibited.

Therefore, when bighead carp is used as the main farmed fish, it can only or must be paired with a small amount of silver carp to promote the growth of the main bighead carp. Otherwise, the bighead carp will also grow poorly because there are too many phytoplankton and the zooplankton cannot digest and absorb all the phytoplankton, which is also not good for the bighead carp.

At present, under normal conditions, when mixed breeding of silver carp and bighead carp is carried out, there are about 200-300 fish per acre, including 150-200 silver carp and 50-100 bighead carp.

The prospect of returning to the countryside to raise fish is very good now. Silver carp has higher economic benefits.