中国体育彩票11选5湖北开奖结果 www.xlzjp.com Common algae in freshwater aquaculture are roughly divided into: cyanobacteria, Euglocalae, Phyllostachys, Dinophyta, Cryptophyta, Diatophyta, Chlorophyta, Dicranophyta and so on. (Non-digestible), fluttering algae (not easy to digest), flat algae, spruce, algae, microcystis (easy to digest), microcystis Produce bloom). Some of them are beneficial algae, and some are harmful algae.
The habit of cyanobacteria
The occurrence of cyanobacteria depends largely on the temperature. Cyanobacteria breeding temperature-sensitive, water temperature below 17 will not occur in large quantities, or will not harm the fish. When the water temperature rose to 28 , due to the growth of other algae are inhibited, while a large number of fish swallowed (high temperature fish feeding metabolic enhancement), cyanobacteria is easy to form a dominant population and a large number of outbreaks.
Algae like alkaline water, high pH (pH8.0 ~ pH9.5) will promote the occurrence of cyanobacteria, it should avoid a single method of using lime water to improve water quality.
2. Nitrogen and phosphorus ratio:
Cyanobacteria can use nitrogen in water and have higher ability to utilize phosphorus, low nitrogen to phosphorus or higher eutrophic water can lead to a large number of cyanobacteria. The appropriate increase in nitrogen and phosphorus ratio can be inhibited to a certain extent the growth of cyanobacteria.
3. Ecological relations:
Cyanobacteria, together with other algae, constitute producers of pond ecosystems, providing more than 89% dissolved oxygen. So these producers in addition to participate in the ecosystem of the material cycle, but also affect the survival of fish.
4. The origin of cyanobacteria bloom:
Different stages of the key factors are different, the general can be the formation of cyanobacteria bloom is divided into four stages: dormancy, recovery, increased biomass, floating. Floating after the formation of cyanobacteria bloom, and then began to turn water.
5. Hazards of cyanobacteria:
Cyanobacteria can change the pressure, in the case of high temperature and strong light weather, gathered in the surface of the water body, absorb most of the sun, in their own large number of breeding while inhibiting the growth of other algae. The proliferation of cyanobacteria, the constant secretion of toxic metabolites to the water body, thus affecting the population of plankton succession, breeding cycle, but also can cause a large number of zooplankton deaths.
Cyanobacteria is a lot of damage
Cyanobacteria particles are difficult to digest by fish, after a large number of breeding will soon become the absolute dominant population. This kind of space through the competition to form the excessive breeding, will inevitably bring in the struggle, this infighting results will lead to a large number of blue algae death. The large number of deaths of cyanobacteria caused the producers of water bodies to drop sharply, resulting in a serious shortage of dissolved oxygen in the water. At the same time, cyanobacteria death decomposition will consume a lot of dissolved oxygen, the release of a large number of hydroxylamine, hydrogen sulfide and other toxic substances. In the case of severe hypoxia and toxic substances, fish, shrimp, crabs will die, or even all die.
Control the method of cyanobacteria
1. thoroughly clear pond disinfection, filling without fresh water with cyanobacteria:
As cyanobacteria are more competitive than other algae, the control measures are mainly preventive and prevent the disease. Completely clear pond disinfection can effectively kill cyanobacteria, reduce the base, can reduce the possibility of large-scale occurrence. At the same time should be noted that with the water into the cyanobacteria, the control of cyanobacteria also have a positive meaning.
2. Regularly change the water:
For ponds with more cyanobacteria, often a lot of fresh water, can dilute the concentration of cyanobacteria. It also dilutes the concentration of toxicants secreted by cyanobacteria, promotes the growth of other algae and maintains the dynamic balance of the entire ecosystem. When a large number of cyanobacteria occur, you can choose to fight algae algae local algae, three days after re-cultivation of algae.
3. stocking a certain number of filter feed fish:
Although cyanobacteria are not easily digested, but because of its larger particles, it is easier to be fed to the body of food, to a certain extent, delay, hinder the growth of cyanobacteria. Alternative fish are silver carp, silver carp, white crucian carp and so on. Practice shows that the stocking of a certain amount of filter fish, the basic outbreak of cyanobacteria.
1. The occurrence of algae blooms produce algae bloom water environment:
Eggs grow in the organic matter rich, still no water in the small water body, and in the nutrient adequacy of a large number of breeding water bloom, become the dominant species in the water quickly occupied the entire water surface.
2. Fenghua formation of the appropriate temperature and season:
The temperature range of the algae is suitable for survival. The suitable temperature for bloom formation is 20 ~ 35 ��, and the growth period spans spring, summer and autumn, especially in 6, 7, 8 and 9 months.
3. Hazard of Eggs:
Nectar is difficult to digest, the utilization rate is low, the fish do not like feeding; algae a large number of deaths easily corrupt water quality, secreted substances also fish, shrimp, crabs produce toxic effects.
4. Eggs control:
A large number of water, so that the formation of micro-water water. As the eugenia hi in the organic matter rich, still no water flow of small water, a large number of water can change this environment, making the algae is not easy in the water or new water reproduction. Can also be used to kill algae algae algae, three days after the use of fertilizer and fertilizer, have a good effect.
1. The occurrence of three golden algae:
Mainly in the coastal saline-alkali areas of higher salinity ponds. The disease water is thin, there is no other algae in the water, the water color is light yellow.
2. San Mao Jin algae poisoning symptoms:
The pool surface covered with fish, mostly in the four corners and shallow water, the head toward the shore, arranged neatly, still resting in the water, nor floating head, disturbed and no response. Randomized fishing on the verge of death of silver carp, carp observation, body surface fins can be found in the base of the congestion, the fish behind the lighter color; open the gill cover found a large number of gills within the gill, gill silk mild rot; anatomical fish, intestinal Food, no obvious lesions.
3. San Mao Jin algae control:
To the pool into the water quality of fertilizer or near the pond of fertilizer, poisoning symptoms can be temporarily alleviated. Quanchiposa 20g / m3 of ammonium sulfate, so that the water in the ammonia up to 0.06 ~ 0.10g / m3, in order to inhibit or kill San Mao Jin.
Dinoflagellates, dacron algae
Dinoflag like to grow in organic matter, hardness, slightly alkaline water. They are Dali breeding, the water was red brown commonly known as "red water."
Dinoflagellate hazards: dinoflagellate for a large group of flagella algae in general, the body was oval, a large number of breeding, can often change the color of their living waters, some dinoflagellate can be used as some aquatic larvae of food, but some of them Group, in the breeding process, can produce a variety of toxins, causing fish numbness, metabolic disorders and respiratory disorders, and finally lead to death. Ovidia can also be attached to the fish body, parasitic life, absorption of fish nutrients to stimulate the fish hyperplastic mucus, so that the fish like a layer of rice coated like a powder, so called "powder", dinoflagate prevention and control with Cyanobacteria
The advantages of hidden algae Cryptophyta is one of the most important flagellates in natural waters, and the reservoirs rich in algae are of high productivity. (50% to 70%), and some species, such as Cryptom onas ovata, also contain more abundant unsaturated fatty acids, especially GLA with high nutritional value Octadecatrienoic acid) and EPA (eicosapentaenoic acid), which account for 20%, 16% and 4% of the total fatty acid content, respectively. Cryptomeria has a high nutritional value, coupled with its cellulose-free cell wall easily digested and absorbed. Thus, it is one of the high quality bait for fish and some precious aquaculture animals
The shortcomings of hidden algae: Cryptococcus algae growth cycle is shorter, easy to die, water color is grayish brown.
Diatoms: small algae, boat algae, straight algae, feather algae
The advantage of diatoms is:
Individual small, palatability is good. Exercise speed and distribution consistent with the habits of larvae, easy to feed, that is, more opportunities for feeding. Nutrient-rich and easy to digest and absorb, itself and its metabolites non-toxic, does not affect the larvae, seed normal growth. Is conducive to excellent floating single cell algae breeding, protection of fish, shrimp nutrient sufficient to ensure that fish, shrimp eat long fast, enhance disease resistance and improve survival rate. Efficient, no residue, to protect the breeding environment, stable water quality, do not pollute the pond. Effectively reduce the ammonia content of water, dissolved oxygen high, good water color.
Chlorella: Cynanchum mongolicus, Crescent algae, Chlorella algae, Chlorella algae, Platycladus orientalis, Streptococcus algae, water net algae (harmful to fry), spiroby (watery filamentous algae) The
1. Application of green algae:
As the green algae is easy to cultivate, thin cell wall, nutrient-rich and other characteristics, mainly as a bait used in aquaculture.
2. The advantages and disadvantages of green algae:
In our pond culture in a large number of growth for the Chlorella, because of its small individual, nutrient-rich, is the excellent rot pulp material. Can make the body produce a large number of rotifers, more suitable for fish, shrimp, crab seedling cultivation. Can be directly as aquatic seedlings of the opening bait, but also cultivate rotifers used to feed seedlings; but because of its individual smaller, the breeding of finished fish for its utilization rate is not high, can be used as a water transfer products.
Yellow algae, knot mouth algae
Yellow algae, knee mouth algae in the warm season, often appear in the fertile fish pond water. A large number of breeding, the formation of cloud-like bloom, water was yellow-green. It is a good bait for silver carp and bighead carp. Winter primary productivity is concentrated in temperate or eutrophic lakes; in winter, low-light, short-day and low-temperature, phytoplankton productivity and biomass are generally low. When the water is cold, if the ice is not thick and no snow cover, ice under the illumination is usually much higher than the algae compensation point, photosynthesis can still be carried out to varying degrees. When the ice is composed of thick black ice or long-term snow on the ice, the net yield turns negative, and the biomass is reduced to the lowest point due to the sinking of the turbidity algae.
The phytoplankton is composed of algae, algae, algae and other algae.
Spring is the first large increase in diatom population. The peak period of the diatoms is generally no more than 3 months, and thereafter the population begins to fade and be green algae or some of the cells due to the depletion of silicate (<0.5 mg / L) or other causes (animal filtration, fungal parasites, etc.) Algae replaced. During this period, if the production layer of nutrients can be added in time, productivity is still high.
In summer and autumn, with the development of green algae, the nitrogen content in water dropped to very low point, so after the midsummer nitrogen nitrogen cyanobacteria (Anabaena sp. The dominant reason for cyanobacteria is also related to high temperatures (above 25 ° C), strong light, high pH, and less feeding. The biomass of cyanobacteria is very high, but the productivity is usually decreased.
Autumn light weakened and the temperature drop and other reasons, will cause the cyanobacteria population suddenly subsided.
Since then, with the vertical mixing of the water in the autumn, the environmental conditions are similar to those in the spring, resulting in the second peak of diatoms.