Fish Health Reviewer PDF

1. ) Bacterial Diseases in Aquaculture What are Bacteria? - Bacteria are microscopic, single-celled organisms that lack a nucleus (prokaryotic). - They are ubiquitous, found in various environments including water, soil, and living organisms. - Bacteria reproduce asexually by binary fission, dividi...

1. ) Bacterial Diseases in Aquaculture What are Bacteria? - Bacteria are microscopic, single-celled organisms that lack a nucleus (prokaryotic). - They are ubiquitous, found in various environments including water, soil, and living organisms. - Bacteria reproduce asexually by binary fission, dividing into two identical daughter cells. - They are classified based on their shape (cocci, bacilli, spiral), gram staining (positive or negative), and biochemical properties. - Some bacteria are beneficial, while others are pathogenic (disease-causing). - Pathogenic bacteria can cause disease by producing toxins, invading tissues, and disrupting normal bodily functions. Identifying the Real Cause of a Disease: Koch's Postulates Koch's Postulates are a set of criteria used to establish a causal relationship between a specific microorganism and a specific disease. They include: 1. The organism should be found in all cases of the disease in question. 2. The organism should be cultivated outside the body of the host in pure culture. 3. The organism so isolated should reproduce the disease when introduced into other susceptible animals. 4. The organism must be reisolated from the experimentally-infected animal. Major Bacterial Diseases of Fish Columnaris Disease - Causative Agent: Flavobacterium columnare (previously Flexibacter columnaris) - Species Affected: Ayu, tilapia, carp, channel catfish, goldfish, rohu - Signs: White spots on the head, gills, fins, or body, often surrounded by a reddish zone. Lesions can develop into hemorrhagic ulcers. - Effects: Gill lesions can cause respiratory difficulty, leading to death. - Prevention and Control: Vaccination, environmental manipulation, addition of competitive bacteria, copper sulfate dip, oxolinic acid dip, sulphamerazine and oxytetracycline treatments. Edwardsiella Septicaemia or Edwardsiellosis - Causative Agent: Edwardsiella tarda - Species Affected: Tilapia, channel catfish, mullet, carp - Signs: Small, cutaneous lesions that progress into abscesses. Internal hyperemia, enlargement of the liver and kidney. - Effects: Loss of mobility, lesions in dermis, musculature, and visceral organs. - Prevention and Control: Improve water quality, reduce stocking density, oxytetracycline treatment. Vibriosis Causative Agents: Vibrio alginolyticus, V. anguillarum, and V. vulnificus - Species Affected: Grouper, rabbitfish, milkfish, seabass, sea bream - Signs: Anorexia, darkening of body color, hemorrhagic spots, necrotic fins, eye opacity, exophthalmia. - Effects: High mortalities, especially in young fish. - Prevention and Control: Maintain good water quality, good husbandry procedures, lower stocking densities, oxytetracycline or nitrofurazone treatment, vaccination. Motile Aeromonad Septicemia - Causative Agents: Aeromonas hydrophila, A. caviae, and A. sobria - Species Affected: Tilapia, milkfish, goldfish, catfish, snakehead, goby, climbing perch, gourami, mullet - Signs: Darkening in color, enlarged abdominal area, superficial reddening, necrosis of fins or tail, extensive ulceration. - Effects: High mortalities, especially in stressed fish. - Prevention and Control: Avoid overcrowding, maintain proper stock management procedures, ensure water quality, reduce stocking density. Pseudomonad Septicemia or Red Spot Disease - Causative Agents: Pseudomonas fluorescens, P. anguilliseptica, and P. chlororaphis - Species Affected: Milkfish, goldfish, tilapia - Signs: Small hemorrhages in the skin, oozing blood and slime, no reddening of fins and anus. - Effects: High mortalities, especially in stressed fish. - Prevention and Control: Maintain proper stock management procedures, ensure water quality, reduce stocking density, transfer to a tank and raise temperature. Streptococcal Infection - Causative Agent: Streptococcus sp. - Species Affected: Seabass, tilapia, rabbitfish, ayu - Signs: Erratic swimming, darkening of body color, exopthalmia, corneal opacity, hemorrhages, ulceration. - Effects: Respiratory difficulties, loss of equilibrium, blindness, high mortalities. - Prevention and Control: Avoid overcrowding, overfeeding, and unnecessary handling, remove moribund fish promptly, erythromycin treatment. Mycobacteriosis or Piscine Tuberculosis - Causative Agent: Mycobacterium marinum, M. fortuitum, and M. chelonae - Species Affected: Siamese fighting fish - Signs: Listlessness, anorexia, emaciation, exopthalmia, skin discoloration, external lesions (nodules, ulcers, fin necrosis). - Effects: Chronic, progressive disease, leading to skeletal deformities, emaciation, edema, and death. - Prevention and Control: Sanitation, disinfection, destruction of carrier fishes, avoid feeding fish with contaminated fish products, pasteurize food, chloramine treatment. Major Bacterial Diseases of Crustaceans - Bacterial Fouling of Surfaces - Filamentous Bacterial Disease: - Causative Agents: Leucothrix sp., Thiothrix sp., Flexibacter sp., Cytophaga sp., Flavobacterium sp. - Species Affected: Penaeus monodon, P. merguiensis, P. indicus - Signs: Fine, colorless, thread-like growth on the body surface and gills. - Effects: Impaired respiration, feeding, locomotion, and molting, leading to slow growth, retarded development, and death. - Prevention and Control: Maintain good water quality, Cutrine Plus or copper treatment. - Cuticular or Subcuticular Localized Infections - Shell Disease, Brown/Black Spot, Black Rot/Erosion, Blisters, Necrosis of Appendages: - Causative Agents: Shell-degrading bacteria belonging to Vibrio, Aeromonas, and Pseudomonas groups. - Species Affected: Penaeus monodon, P. merguiensis, P. indicus - Signs: Brownish to black, eroded areas on the cuticle, appendages, and gills. - Effects: Progressive destruction of the cuticle, leading to osmotic imbalances, molting problems, secondary fungal infection, and death. - Prevention and Control: Maintain good water quality, use nutritionally adequate diets, minimize handling and overcrowding, avoid injuries to the exoskeleton. Internal or Systemic Infections - Luminous Bacterial Disease: - Causative Agents: Vibrio harveyi and V. splendidus - Species Affected: Penaeus monodon, P. merguiensis, P. indicus - Signs: Weak and opaque-white shrimps, greenish glow in total darkness, densely packed bacteria in hemocoel and internal tissues. - Effects: Severe inflammation in the hepatopancreas, leading to digestive dysfunction and death. - Prevention and Control: Disinfect incoming water, use only previously disinfected water during spawning and rearing, wash eggs, siphon sediments, disinfect infected stock, use probiotics, monitor bacterial population, practice crop rotation, install greenwater culture system, apply antibiotics as a last resort. Non-luminous Vibrios: - Causative Agents: Vibrio parahaemolyticus, V. alginolyticus, V. anguillarum, V. vulnificus, V. damsela, V. fluvialis, and V. penaeicida - Species Affected: Penaeus monodon, P. vannamei, P. japonicus - Signs: Erratic swimming, loss of appetite, opaqueness of abdominal muscle, melanization, necrosis of appendage tips. - Effects: High mortalities, especially in stressed shrimp. - Prevention and Control: Maintain good water quality, use nutritionally adequate diets, minimize handling and overcrowding, apply probiotics, practice crop rotation, install greenwater culture system, perform immunoprophylaxis or vaccination, apply antibiotics as a last resort. Other Important Details - Stress Factors: Poor water quality, inadequate food, overcrowding, handling, and transport can increase susceptibility to bacterial infections. - Diagnosis: Microscopic examination of affected tissues, isolation and identification of the causative bacteria, and serological tests. - Prevention: Maintain good water quality, use nutritionally adequate diets, minimize handling and overcrowding, and avoid injuries. - Control: Use of antibiotics, vaccination, and other biological control methods. - Importance: Bacterial diseases can cause significant economic losses in aquaculture, impacting production and profitability. 2.)Fungal Diseases in Aquaculture What are Fungi? - Fungi are heterotrophic organisms, lacking chlorophyll, historically compared to plants. - They are usually filamentous and multicellular, although some are non-filamentous and unicellular. - The filaments, known as hyphae, constitute the body of a fungus. - Hyphae can be septate (divided by cross walls) or non-septate (coenocytic, without cross walls). - Fungi reproduce by both asexual and sexual means, producing different kinds of spores. - Fungal cell walls are primarily made up of chitin. - Fungi exhibit absorptive nutrition, capable of utilizing almost any carbon source as food. - Many fungi are saprobes (saprotrophs), obtaining their food from dead or decaying organic matter. - A considerable number of species live as parasites of plants, animals, and in some cases, even other fungi. Major Fungal Diseases of Fish Saprolegniosis (Saprolegniasis) - Causative Agents: Saprolegnia spp., Achlya spp., and Aphanomyces spp. - Species Affected: Many freshwater fish (e.g., carps, goldfish) - Signs: White cottony growth on fish eggs and affected tissues. - Effects: Progressive and terminal, leading to lethargy, loss of equilibrium, and death. - Prevention and Control: - Bath treatments with: - Zinc-free malachite green - Sodium chloride - Formalin Epizootic Ulcerative Syndrome (EUS) - Causative Agents: Aphanomyces invadans, rhabdovirus, and Aeromonas hydrophila. - Species Affected: Over 30 freshwater fish species (e.g., snakeheads, catfish, guorami, goby, etc.) - Signs: Darker discoloration, loss of appetite, ulcerative lesions on the body. - Effects: Lethargy, exposed head and bone tissues, visceral organs, and vertebral column. - Prevention and Control: - Eradication of the causative agent. - Prevention of reintroduction. - Proper management by reducing stocking densities. - Farming of EUS-resistant fish species. - Treatments: - 5 ppm Coptrol - 0.1 mg/L malachite green Branchiomycosis (Gill Rot) - Causative Agents: Branchiomyces spp. - Species Affected: Carps, goldfish, eels - Signs: Pale gills with brownish areas due to hemorrhage and thrombosis. - Effects: Fungal hyphae in the gills obstruct blood circulation, leading to necrosis, proliferation of lamellar epithelial cells, and death due to anoxia. - Prevention and Control: - Treatments: - Malachite green - Benzalkonium chloride - Copper sulfate - Sodium chloride - Stop feeding, remove dead fish, drain, dry, and disinfect the pond. Ichthyophoniasis (Ichthyosporidiosis) - Causative Agent: Ichthyophonus sp. (=Ichthyosporidium sp.) - Species Affected: Groupers, trouts, flounders, herrings, and cods - Signs: Erratic swimming behavior, swelling of the abdomen, whitish nodules in internal organs and muscle tissues. - Effects: Loss of appetite, emaciation, anemia. - Prevention and Control: No known treatment. Avoid feeding fish with contaminated trash fish. Major Fungal Diseases of Crustaceans Larval Mycosis - Causative Agents: Lagenidium spp., Sirolpidium spp., Haliphthoros spp. - Species Affected: All Penaeus species, crabs (e.g., Scylla serrata) - Signs: Sudden onset of mortalities in larval stages of shrimps and crabs. - Effects: Progressive systemic mycosis with little or no host inflammatory response. - Prevention and Control: - Disinfection of contaminated larval rearing tanks. - Chlorination and/or filtration of incoming water. - Treatments: - 0.2 ppm Treflan - 1-10 ppm formalin - Egg disinfection with 20 ppm detergent before hatching. Black Gill Disease (Fusarium Disease) - Causative Agent: Fusarium solani - Species Affected: All Penaeus species - Signs: Appearance of “black spots” on damaged tissues, gills, and lesions. - Effects: Progressive infection with 30% remission rate. - Prevention and Control: - Elimination of sources of Fusarium conidiophores. - Destruction of infected individuals. - No effective fungicides in field trials. Aflatoxicosis (Red Disease) - Causative Agent: Aflatoxin produced by Aspergillus flavus and other Aspergillus spp. - Species Affected: Penaeus monodon, other Penaeus spp. - Signs: Yellowish, and eventually reddish discoloration of the shrimp body and appendages, lethargy, weak swimming activity. - Effects: Necrosis in the hepatopancreas, growth retardation. - Prevention and Control: - Do not use moldy feeds. - Properly store feeds in dry and well-ventilated areas. Other Important Details - Stress Factors: Mechanical injury, extreme pH levels, prolonged exposure to low water temperatures, lack of food, and presence of other microbial infections increase susceptibility to fungal infections. - Diagnosis: Microscopic examination of affected tissues to reveal characteristic hyaline and coenocytic mycelia, sporangia, and discharge tubes. - Prevention: Maintain good water quality, use nutritionally adequate diets, minimize handling and overcrowding, and avoid injuries to the exoskeleton. - Control: Use of fungicides, such as malachite green, formalin, and Treflan. - Importance: Fungal diseases can act as major limitations on natural and cultured populations of aquatic animals, posing a threat to the aquaculture industry. 3.)Parasitic Diseases in Aquaculture What are Parasites? - Parasites are organisms that live in or on another organism (the host) and benefit at the host's expense. - They can be classified as ectoparasites (living on the external surface) or endoparasites (living inside the body). - Parasites have complex life cycles, often involving multiple hosts. - They can cause a variety of diseases, ranging from mild infections to severe and fatal conditions. Major Parasitic Diseases of Fish Protozoan Infestations: - Ichthyophthiriasis ("Ich") or White Spot Disease: - Causative Agent: Ichthyophthirius multifiliis (freshwater) and Cryptocaryon irritans (marine and brackishwater) - Species Affected: Catfish, carp, tilapia, seabass, grouper, snapper - Signs: White or grayish spots on the skin and gills, lethargy, loss of appetite, dull eyes, excessive mucus production. - Effects: Destruction of skin and gills, ulceration, secondary bacterial or fungal infections. - Prevention and Control: Increase water temperature, salt baths, formalin treatments, transfer to parasite-free tanks. Trichodiniasis: - Causative Agents: Trichodina, Trichodinella, Tripartiella - Species Affected: Carp, tilapia, milkfish, seabass, mullet, siganid, grouper, snapper - Signs: Attached to gills and skin, weak fish, excessive mucus production, frayed fins. - Effects: Interference with respiration, gill lesions. - Prevention and Control: Salt baths, freshwater baths, formalin and Acriflavin treatments. Amyloodiniasis ("Velvet Disease"): - Causative Agent: Amyloodinium ocellatum - Species Affected: Mullet, siganid, grouper - Signs: Dusty appearance of skin, excessive mucus production, abnormal surface swimming. - Effects: Disintegration of tissues, gill epithelial hyperplasia, reduced mucus cell production. - Prevention and Control: Sand filters, ultraviolet irradiation, disinfection, quarantine, freshwater baths, copper sulfate treatments, formalin treatments. Blood Protozoan Infections: - Causative Agents: Trypanosoma, Cryptobia, Ichthyobodo - Species Affected: Snakehead, carps, mullet, milkfish (blood) - Signs: Greyish-white film on fins and body, frayed fins, sluggishness, pale gills, emaciated body, anemia. - Effects: Interference with respiration, anemia. - Prevention and Control: Drying of culture facilities, use of filters, elimination of vectors (e.g., leeches), potassium permanganate treatments. - Myxosporean Infections: - Causative Agents: Myxidium, Myxobolus, Henneguya, Kudoa, Myxosoma, Thelohanellus - Species Affected: Mullet, catfish, eel, carps, climbing perch, snakehead - Signs: White cysts on skin, gills, muscle, brain, heart, ovaries, or internal organs. - Effects: Respiratory dysfunction, muscle damage, loss of equilibrium, skeletal deformities, tissue destruction. - Prevention and Control: Isolate and destroy infected fish, disinfect rearing facilities. Sphaerosporiasis: - Causative Agent: Sphaerospora - Species Affected: Grouper, seabass, marine catfish - Signs: Swollen abdomen, exophthalmia, anemia. - Effects: Spore stages found in kidney, liver, gall bladder, and blood cells. - Prevention and Control: Ultraviolet treatment of inflow water. Monogenean Infestations: - Gyrodactylosis, Dactylogyrosis, Pseudorhabdosynochus, Benedeniasis: - Causative Agents: Gyrodactylus, Dactylogyrus, Pseudorhabdosynochus, Benedenia - Species Affected: Catfish, carp, tilapia, seabass, grouper, snapper - Signs: Attached to gills, fins, and body surface, pale skin and gills, increased mucus production, frayed fins, corneal opacity. - Effects: Gill epithelial damage, interference with respiration, high mortalities. - Prevention and Control: Maintain optimum stocking density, adequate feeding, salt baths, freshwater baths, formalin treatments, hydrogen peroxide treatments. Digenean Infestations: - Bucephalosis, Lecithochiriasis, Pseudometadeniasis, Transversotrematosis, Stellantchasmus, Haplorchiasis, Proceroviasis, Prosorhynchosis, Hemiuriasis: - Causative Agents: Bucephalus, Lecithochirium, Pseudometadena, Transversotrema, Stellantchasmus, Haplorchis, Procerovum, Prosorhynchus, Hemiurus - Species Affected: Bighead carp, grass carp, milkfish, seabass, grouper, siganid, mullet - Signs: White to yellow or brown to black cysts on skin, fins, gills, muscle, stomach, or intestine. Distended abdomen, growth retardation. - Effects: Growth retardation, disfigurement, disruption of vital organ function. - Prevention and Control: Elimination of intermediate hosts. Cestode Infestations: - Botriocephalosis: - Causative Agent: Botriocephalus - Species Affected: Carps, catfish, snakehead - Signs: Sluggishness, emaciated body, non-feeding. - Effects: Hemorrhagic enteritis, interference with intestinal absorption, reduced food intake. - Prevention and Control: Elimination of intermediate hosts, disinfection of culture facilities. Nematode Infestations: - Spirocamallanosis, Raphidascaridosis, Contracaecum, Echinocephalosis: - Causative Agents: Spirocamallanus, Raphidascaris, Contracaecum, Echinocephalus - Species Affected: Siganid, grouper, catfish, snakehead, goby - Signs: Parasites in stomach and intestine, emaciated body, discolored body surface, swollen intestine. - Effects: Necrotic hemorrhagic ulcers in the intestine, growth retardation, high mortalities. - Prevention and Control: Elimination of intermediate hosts, drying of pond bottom, disinfection of culture facilities. Acanthocephalan Infestations: - Acanthocephalosis, Pallisentiasis: - Causative Agents: Acanthocephalus, Pallisentis - Species Affected: Snakehead, catfish, eel, tilapia, milkfish - Signs: Attached to intestinal mucosa, darkened and emaciated body. - Effects: Necrotic hemorrhagic ulcers in the intestine, growth retardation, high mortalities. - Prevention and Control: Disinfect pond with quicklime, control water supply and potential intermediate hosts, quarantine new stocks. Major Parasitic Diseases of Crustaceans Protozoan Infestations: Vorticella, Zoothamnium, Epistylis, Acineta, Ephelota: - Causative Agents: Vorticella, Zoothamnium, Epistylis, Acineta, Ephelota - Species Affected: Shrimps, crabs - Signs: Fuzzy mat on gills and body surface. - Effects: Respiratory and locomotory difficulties, high mortalities. - Prevention and Control: Removal of organic detritus, rigid sanitary control of rearing water, formalin treatments. - Sporozoan Infestations: - Gregarines: - Causative Agent: Gregarines - Species Affected: Penaeid shrimps - Signs: Gregarines may be detected in the digestive tract microscopically. - Effects: Interference with filtration of particles, growth retardation. - Prevention and Control: Filter or chlorinate seawater in the hatchery, eliminate molluscan intermediate host in grow-out ponds. - Microsporidian Infections: - Causative Agents: Nosema (Ameson), Agmasoma (Thelohania), Pleistophora, Glugea, Ichthyosporidium - Species Affected: Penaeid shrimps - Signs: Weakened and easily stressed shrimps, opaque white areas (cephalothorax, abdominal muscle, ovary), "cotton" or "milk" shrimp, "white ovary" disease. - Effects: Sterility of spawners, lysis of muscle tissues. - Prevention and Control: Isolate and destroy infected individuals, avoid contact of infected broodstock with offspring, disinfect culture systems. Life Cycle Patterns of Fish Parasites - Direct Life Cycle: The parasite completes its life cycle in a single host (e.g., Ichthyophthirius, Monogeneans). - Indirect Life Cycle: The parasite requires multiple hosts to complete its life cycle (e.g., Digeneans, Cestodes, Nematodes, Acanthocephalans). Other Important Details - Stress Factors: Poor water quality, overcrowding, handling, and transport can increase susceptibility to parasitic infections. - Diagnosis: Microscopic examination of affected tissues, isolation and identification of the causative parasites. - Prevention: Maintain good water quality, use nutritionally adequate diets, minimize handling and overcrowding, and avoid injuries. - Control: Use of chemicals (e.g., formalin, copper sulfate), biological control methods (e.g., elimination of intermediate hosts), and quarantine procedures. - Importance: Parasitic diseases can cause significant economic losses in aquaculture, impacting production and profitability. 4.) Environmental and Non-Infectious Diseases in Aquaculture Environmental and Non-Infectious Diseases - Environmental diseases are caused by adverse conditions in the aquatic environment, such as poor water quality, extreme temperatures, and toxicants. - Non-infectious diseases are not caused by pathogens but by factors like nutritional deficiencies, genetic defects, or physical injuries. - These diseases are not contagious, but they can be just as detrimental to aquaculture as infectious diseases. Major Environmental and Non-Infectious Diseases of Fish Gas Bubble Disease: - Cause: Supersaturation of dissolved gases (nitrogen or oxygen) due to leaks in pump systems, dense algal blooms, or other factors. - Species Affected: Many freshwater and marine fish species. - Signs: Bubbles in the abdominal cavity, eyes, skin, gills, fins, mouth, swimbladder, and digestive tract. Exophthalmia (bulging eyes). - Effects: Embolism in blood, emphysema in tissues, edema and degeneration of gill lamellae, corneal bulging, mass mortalities. - Prevention and Control: Monitor dissolved oxygen, avoid algal blooms, maintain efficient operation of waterlines and pumps, sufficient water exchange. Swimbladder Stress Syndrome (SBSS): - Cause: Malfunction of the swimbladder, often associated with handling, high temperature, high illumination, and dense algal blooms. - Species Affected: Fish larvae, especially seabass. - Signs: Large gas bubble in the region antero-dorsal to and outside the swimbladder. - Effects: Hyperinflation of swimbladder, high positive buoyancy, mass mortalities. - Prevention and Control: Filter rearing water, regulate algal blooms, provide strong aeration. Asphyxiation/Hypoxia: - Cause: Very low levels of dissolved oxygen due to high organic load, algal bloom die- off, or high temperature. - Species Affected: Many fish species. - Signs: Fish gathering at water inlets and outlets, gaping mouth, surface swimming, rapid opercular movement. - Effects: Death due to oxygen deprivation. - Prevention and Control: Monitor dissolved oxygen levels, provide aeration. High Salinity: - Cause: Extremely high salinities. - Species Affected: Fish species. - Signs: Progressive emaciation, scale loss, opaque eye lenses. - Effects: Disruption of osmotic balance, leading to death. - Prevention and Control: Monitor salinity levels, maintain optimal salinity for the species. Alkalosis: - Cause: Water pH becomes too basic (high). - Species Affected: Fish species. - Signs: Corroded skin and gills, milky turbidity of the skin. - Effects: Disruption of pH balance, leading to death. - Prevention and Control: Monitor pH levels, maintain optimal pH for the species. Acidosis: - Cause: Water pH becomes too acidic (low). - Species Affected: Fish species. - Signs: Rapid swimming movements, gasping, increased mucus secretion, rapid death. - Effects: Disruption of pH balance, leading to death. - Prevention and Control: Monitor pH levels, maintain optimal pH for the species. Sunburn Disease: - Cause: Excessive ultraviolet (UV) radiation from sunlight, especially in shallow, uncovered raceways. - Species Affected: Fish species. - Signs: Gray, focal, circular, ulcerative lesions on the head, fins, and tail. - Effects: Ulceration, secondary infections. - Prevention and Control: Place sunshades over ponds, keep fish away from UV installations. Major Environmental and Non-Infectious Diseases of Shrimp - Muscle Necrosis: - Cause: Temperature and salinity shock, low oxygen levels, overcrowding, rough handling, and severe gill fouling. - Species Affected: Penaeid shrimp. - Signs: Opaque white areas on the abdomen, blackening on the edges of the uropod, "wood grain" appearance of abdominal muscle in postlarvae. - Effects: Gradual death of cells, erosion, secondary bacterial infections. - Prevention and Control: Reduce stocking density, improve water quality, daily water change. Bent/Cramped Tails or Body Cramp: - Cause: Handling in warm, humid air, mineral imbalance. - Species Affected: Shrimp species. - Signs: Partial or complete rigid flexure of the tail. - Effects: Impaired swimming, cannibalism. - Prevention and Control: Avoid possible causes. Incomplete Molting: - Cause: Low temperature of culture water. - Species Affected: Shrimp larvae. - Signs: Presence of old exoskeleton attached to newly molted larvae. - Effects: Abnormal swimming, predation, mortality. - Prevention and Control: Maintain optimal temperature, use water heaters. Asphyxiation/Hypoxia: - Cause: High organic load, algal bloom die-off, high temperature. - Species Affected: Shrimp species. - Signs: Surface swimming, sudden mass mortality. - Effects: Death due to oxygen deprivation. - Prevention and Control: Decrease stocking density, monitor water parameters, provide aeration. Acidosis/Acid Sulfate Disease: - Cause: Low water and soil pH. - Species Affected: Shrimp species. - Signs: Poor growth, low molting frequency, yellow to orange to brown discoloration of gills and appendages, reddish pond soil. - Effects: Disruption of pH balance, retarded growth, death. - Prevention and Control: Monitor pH, apply lime and flush the ponds before stocking. Black Gill Disease: - Cause: Chemical contaminants, heavy siltation, ammonia or nitrite in rearing water, high organic load. - Species Affected: Shrimp species. - Signs: Reddish, brownish to black discoloration of gills, black gill filaments. - Effects: Tissue necrosis, melanin deposition. - Prevention and Control: Avoid heavy metal discharges, remove black soil, drain pond water from the bottom. Red Disease: - Cause: High lime application, prolonged exposure to low salinity. - Species Affected: Shrimp species. - Signs: Red streaks on gills or abdominal segments, yellowish to reddish discoloration of the body, increased fluid in the cephalothorax. - Effects: Hemocytic infiltration in the hepatopancreas, necrosis, melanized encapsulation of necrotic tissues. - Prevention and Control: Prepare pond bottom properly, reduce lime and organic matter inputs. Chronic Soft-Shell Syndrome: - Cause: Exposure to pesticides and piscicides. - Species Affected: Shrimp species. - Signs: Thin and persistently soft shell, dark, rough, and wrinkled shell surface, weak shrimps. - Effects: Soft-shelled, slow growth, death. - Prevention and Control: Flush ponds thoroughly, maintain good water quality. Diseases Associated with Physical Factors - Handling, Transport, High Stocking Density, Predation: These factors can cause physical injuries, leading to secondary infections. Diagnosis of Environmental and Non-Infectious Diseases - Gross Examination: Observe external and internal signs. - Histopathological/Histochemical Analysis: Examine tissue samples. - Hematological Analysis: Assess blood cell composition. - Water Quality Analysis: Monitor physico-chemical parameters. - Evaluation of Culture Operations: Assess management practices. Other Important Details - Stress: Environmental and non-infectious diseases are often exacerbated by stress. - Prevention: Maintaining good water quality, optimal environmental conditions, and proper management practices is crucial. - Control: Addressing the underlying causes of the disease is essential. - Importance: These diseases can cause significant economic losses in aquaculture, impacting production and profitability. 5..) Nutritional Diseases in Aquaculture Nutritional Diseases - Nutritional diseases arise from a deficiency (undernutrition), excess (overnutrition), or imbalance (malnutrition) of essential nutrients in an animal's diet. - They develop gradually as animals have body reserves that can compensate for a period. - Nutritional deficiencies can weaken the immune system, making animals more susceptible to other diseases. Major Nutritional Diseases of Fish Amino Acid Deficiency Syndrome: - Cause: Lack of essential amino acids in the diet. - Species Affected: All fish species. - Signs: Reduced or cessation of growth, poor feed conversion, lethargy, anemia, skeletal deformities. - Effects: Impaired growth, reduced disease resistance, poor reproductive performance. - Prevention and Control: Provide a balanced diet with adequate levels of all essential amino acids, use high-quality protein sources (e.g., fishmeal). Fats and Lipids Deficiency Syndrome: - Cause: Lack of essential fatty acids in the diet. - Species Affected: All fish species. - Signs: Depigmentation, fin erosion, cardiac myopathy, fatty infiltration of the liver (lipoid liver disease). - Effects: Impaired growth, reduced disease resistance, poor reproductive performance. - Prevention and Control: Provide a diet with adequate levels of essential fatty acids, use high-quality lipid sources (e.g., fish oil), avoid rancid fats. Vitamin Deficiencies: - Cause: Lack of specific vitamins in the diet. - Species Affected: All fish species. - Signs: Anemia, anorexia, ascites, atrophy, cartilage abnormalities, cataracts, cloudy lens, clubbed gills, decoloration, bone deformities, low disease resistance, edema, equilibrium loss, fin erosion, exophthalmia, fatty liver, poor feed conversion, fin fragility, poor growth, low hemoglobin, hemorrhage, lethargy, lipoid liver, lordosis, low liver glycogen, myopathy, necrosis, pinhead syndrome, iris pigmentation, scoliosis, erratic swimming, vacuolation. - Effects: Wide range of symptoms, depending on the specific vitamin deficiency. - Prevention and Control: Provide a diet with adequate levels of all essential vitamins, use high-quality vitamin sources, avoid vitamin degradation during feed storage. Mineral Deficiencies: - Cause: Lack of specific minerals in the diet. - Species Affected: All fish species. - Signs: Anemia, bone deformities, skeletal abnormalities, poor growth, low disease resistance, muscle weakness, skin lesions. - Effects: Impaired growth, reduced disease resistance, poor reproductive performance. - Prevention and Control: Provide a diet with adequate levels of all essential minerals, use high-quality mineral sources. Major Nutritional Diseases of Shrimp Vitamin C Deficiency (Black Death Disease): - Cause: Low levels of vitamin C in the diet, lack of algal growth or other vitamin C sources. - Species Affected: Penaeid shrimp. - Signs: Black lesions beneath the cuticle, slow growth, susceptibility to shell disease. - Effects: Reduced immune function, impaired wound healing, increased susceptibility to infections. - Prevention and Control: Provide a diet with adequate levels of vitamin C, use stable forms of vitamin C in feed. Chronic Soft-Shell Syndrome: - Cause: Inadequate feeding, insufficient food supply, atrophied hepatopancreas. - Species Affected: Penaeid shrimp, especially Penaeus monodon. - Signs: Thin and persistently soft shell, dark, rough, and wrinkled shell surface, weak shrimps. - Effects: Soft-shelled, slow growth, increased susceptibility to infections, reduced market value. - Prevention and Control: Provide adequate feeding, monitor shrimp biomass, improve water quality. Blue Disease or Blue Shell Syndrome: - Cause: Deficiency in dietary carotenoids (e.g., astaxanthin). - Species Affected: Penaeid shrimp, especially Penaeus monodon. - Signs: Light blue body color. - Effects: Reduced pigmentation, potential impact on growth and survival. - Prevention and Control: Provide a diet with adequate levels of carotenoids. Body Cramp or Cramped Tail Syndrome: - Cause: Imbalance in calcium:magnesium ratio, vitamin B deficiency. - Species Affected: Shrimp species. - Signs: Partial or complete rigid flexure of the tail. - Effects: Impaired swimming, cannibalism. - Prevention and Control: Maintain balanced mineral levels in the diet. Underfeeding: - Cause: Inadequate feeding rates, insufficient food supply, lack of specific nutrients. - Species Affected: Shrimp species. - Signs: Loose and oversized shells, atrophied hepatopancreas, reduced growth. - Effects: Impaired growth, increased susceptibility to infections. - Prevention and Control: Monitor shrimp biomass, provide adequate feeding rates, ensure balanced nutrient levels in the diet. Feed Quality Problems with Health Implications - Improper Storage: - Effects: Loss of vitamins and nutrients, rancidity, contamination with microorganisms and toxins. - Prevention and Control: Store feeds in cool, dry, and well-ventilated areas, avoid moisture, use mold inhibitors. - Aflatoxin Contamination: - Cause: Presence of aflatoxin produced by Aspergillus flavus and other Aspergillus species in feed ingredients. - Species Affected: Shrimp species. - Signs: Melanized tubules in the hepatopancreas, reduced growth, susceptibility to shell disease. - Effects: Hepatopancreas dysfunction, impaired growth, reduced immune function. - Prevention and Control: Avoid using moldy feeds, store feeds properly, test feed ingredients for aflatoxin. Toxic Components in the Diet: - Cause: Presence of toxins in feed ingredients (e.g., gossypol, phytic acid, chlorinated hydrocarbons). - Species Affected: All fish and shrimp species. - Signs: Anorexia, liver damage, reduced growth, mortality. - Effects: Impaired growth, reduced immune function, potential for toxicity. - Prevention and Control: Use high-quality feed ingredients, avoid using contaminated ingredients, properly process feed ingredients to eliminate toxins. Transmission of Diseases Through Trash Fish: - Cause: Feeding fish with contaminated trash fish. - Species Affected: Fish species. - Signs: Signs of the specific disease transmitted. - Effects: Transmission of bacterial, viral, or parasitic diseases. - Prevention and Control: Avoid using contaminated trash fish, freeze or heat-treat trash fish before feeding. Other Important Details - Diagnosis: Requires a combination of clinical signs, blood chemistry, hematology, tissue analysis, and feed analysis. - Prevention: Providing a balanced diet with adequate levels of all essential nutrients is crucial. - Control: Addressing the underlying nutritional deficiencies or imbalances is essential. - Importance: Nutritional diseases can have a significant impact on aquaculture production, leading to reduced growth, increased mortality, and reduced profitability.