Proper pond management involves a regular and steady supply of nutrient for sustained production of fish food organisms. The supply of nutrients could be from within the pond itself or from outside. It is also required to regulate the physico-chemical parameters of the pond ecosystem within the safe tolerance limits of the cultured fish species. This necessitates periodical monitoring of pond environment and taking corrective measures in time. Most of the parameters can be easily measured at the pond site while some require laboratory facilities. The monitoring gives reliable guidelines for fish farmers to optimize fish production.
Parameters to be Monitored
It is essential for extension workers to name and code-number the ponds in their area. Such coding may be based either on postal district/unit/village farmer's name, etc. The fish farmer should record the following information on his fish farm:
Nature of pond: Perennial or seasonal; nursery pond, rearing pond or stocking pond.
Water area: Measurement of the water area is essential in order to know the size of the pond for proper fish stocking and quantifying the production processes. This can be done easily with the help of a bamboo pole of known length.
Age: Age is one of the most important parameters, since it has direct relevance with the productivity of the pond which usually varies from one year to several hundred years.
Management: Management status should record the existing management techniques and its level (intensive or extensive). The species of fish present, details of culture activities, stocking structure and density, fertilization, feeding, harvesting, marketing, etc, need to be recorded. To obtain qualified data on the organic carbon and biogenic nutrient load it is necessary to know the number of livestock and human population associated with the particular pond.
The fish farmer should also monitor the following parameters on a routine basis.
Water colour: The visual colour of the pond water is a simple but important reflection of the basic production processes.
Water transparency: Water transparency measured with a Secchi disc is intended to quantify the result of those processes which determine and modify the visual colour. However, a low transparency may result either from high turbidity alone or from dense algal population and thus cannot reflect the correct trophic or production level of the water. However, the Secchi transparency readings together with the visual colour provide valuable information on the productivity of the water.
Water depth: The primary water source is usually the rainfall during the monsoon. After the rainy season the water level gradually decreases which results in a very shallow water column by the end of the dry season. The water depth can be measured with a 4–5 m long bamboo pole fitted at its base with a wooden disc of 25 cm dia.
Soft sediment depth: A soft sediment layer is usually present in the pond bottom. The depth of this layer can be measured with a 6–8 m long bamboo pole having a wooden disc of 10 cm dia at its base.
Solid sediment depth: In older ponds, in addition to the soft sediment layer, a solid sediment layer with a low water content is also present. The thickness of the layer can be measured with a 6–8 m long bamboo pole with a sharp end. The total thickness of the soft plus solid sediment layers has a direct relation to the age of the fish pond, at times the sediment layer measures more than 2 m. Such thick sediment, having a rich nutrient content, is anaerobic in nature with slow bacterial decomposition and mineral cycling rates. This should be properly utilized for fish culture.
Chemical environment in the water column: The water is chemically characterized by pH, alkalinity, NH4-N, NO3N and PO4-P measurements following standard methods. Normally the pH and alkalinity do not change from pond to pond on the same types of maternal soil. The measurements of NH4-N, NCO3-N and PO4-P indicate the basic inorganic nutrient status of the pond.' Simple chemical parameters such as dissolved oxygen and pH may be measured using field kits. Slightly alkaline water (pH 7.0–8.5) and oxygen levels of 6–9 ppm indicate optimum condition.
Dawn oxygen: Fish ponds usually exhibit wide fluctuations in the dissolved oxygen content from day to night. This diurnal oxygen fluctuation is normally measured to calculate the community metabolism of the whole pond while quantifying the production and respiration processes in the ecosystem. A single measurement just before sunrise would be an important indicator of the risk of fish kill due to oxygen depletion.
Symptoms: - Brown flakes grow on the body like white cotton wool.
Treatment: - Submerging small ponds in a 1: 1000 potassium solution of 3 percent ordinary salt solution or copper sulphate solution for 1-5 minutes in 1: 1000 potassium solution for 5-10 m water is effective.
Symptoms: - Diseased fish try to drink air on the upper surface due to rotting of the slits, suffocation. Repeatedly opens and closes the mouth.
Treatment: - Prevention of pollution, increasing the level of water in the pond with fresh water or using 50-100 kg / ha of lime or bathing in 3-5% salt solution or in ponds with 0.5 m depth rate of 8 kg / ha Using copper sulphate from.
Symptoms: - Wounds found on the head, body and tail.
Treatment: - Use of potash in the pond at the rate of 5 mg / l, lime 600 kg / ha (3 times at 7 days intervals), cephase solution in 1 liter of water and put it in the pond,
Symptoms: - water in internal organs and in the abdomen.
Treatment: - Proper arrangement of clean water and food to the fish, lime at the rate of 100 kg / ha after 15 days (2-3 times)
Protozoan Disease "Costiasis"
Symptoms: - Small macular disorder on body and gills.
Treatment: - 10 minutes in 50 ppm formiline solution or 10 minutes in 1: 500 glacial acetic acid solution.
Catla Eye Disease
Symptoms: - First symptoms of corneal redness in eyes, fall of eyes at last, faded color of gills etc.
Treatment: - Potash 2-3 ppm, food to teramycin 70-80 mg per kg of fish weight (up to 10 days) , Use of injections according to the weight of streptomycin 25 mg per kg
Ecothiopthyriosis (itching whitening)
Symptoms: - Excessive mucus secretion, small white rash appear on the body.
Treatment: - Every day for 7-10 days, 200 ppm Fargillan solution is used for bathing hours, 2 percent of ordinary solution for more than 7 days. Experiment,
Trichodinosis and Schiffidiosis
Symptoms: - Difficulty in breathing, restless body rubbing on the side of the pond, excessive synovial secretion on the skin and gills,
Treatment on the body: - 2-3% in a simple salt solution (5-10 minutes), 10 pp caper Use of sulphate solution, use of 20-25 ppm formoline
Symptoms: mustard seeds on the skin, monoplasm, gills and apicalum.
Treatment: - Immerse 1-2 equal white lacquer minutes in 0.1 ppm formalin, 50 ppm formalin, 15-25 ppm formalin in the pond every other day, till the disease ends Use, more diseased fish should be killed and the fish should be transferred to another pond.
Symptoms: - Excessive syphilis, secretions, difficulty in breathing and aggravation.
Treatment: - bathing in 2-3% ordinary salt 50 ppm formalin solution for 5-10 minutes or in 1: 500 glacial acetic acid solution (up to 10 minutes)
Dactylogarillosis and Gyradactylosic (Trematodes)
Symptoms: - The outbreak occurs on the gills and skin and black color in the body.
Treatment: - 5 minutes alternately in 1: 2000, acetic acid and sodium chloride 2 percent solution in 500 ppm potashium (gynecological) solution. To bathe.
Diplostomiasis or black spot disease
Symptoms: - Black spots on the body.
Treatment: - The life cycle of the parasite should be broken. Stop snails or birds
Symptoms: - The abdomen swells due to the collection of worms.
Treatment: - The life cycle of the parasite should be broken, for this, life-related organisms snails or birds are not allowed to enter the pond, immersed in 1: 500 Formalin solution for 10 minutes, using 1-3% salt solution.
Symptoms: - Weak deformed form, red small spots on the body etc.
Treatment: - Gumoxin spraying of lime at the rate of 0.1-0.2 g / litre is best to use two to three times in a fortnight after expelling the pond water for 24 hours. is. Dissolve 35 mL spermethylene medicine in 100 litres of water and use it three times in a span of 5-5 days in the pond at the rate of 1 ha.
Larynesis (anchor worm disease)
Symptoms: - bleeding vascularity, weakness and spots on the body.
Treatment: - Due to mild disease infection, use of 1 ppm gamaxine or bromos 50 in the pond at the rate of 0.12 ppm
Other diseases EUS (ulcerative) ulcerative syndrome
Symptoms: - In the initial stage, red spots are found on the body of the fish, which gradually become darker and rot. Ulcers are also found on the belly, head and tail of fish. Finally, the fish dies.
Treatment: - Effective treatment of 600 kg of lime per ha. Cephex 1 litre per hectare is also effective.
Understanding and managing the undrainable pond environment is the key to successful fish health management and profitable fish culture, and to ensure this the knowledge of the role of various environmental components in the occurrence of disease outbreak is essential. The main thrust of such measures is directed toward:
The following important measures are the key components of successful fish health managements:
Source : Department of Fisheries