Odisha CHSE +2 Vocational Inland Fisheries cheat sheet

Unit conversions used in fisheries: 1 hectare = 10,000 m²; 1 m³ = 1,000 L; 1 ppm = 1 mg/L = 1 g/m³; 1 kg/ha of lime spread over 1 ha of 1 m depth gives roughly 1 mg/L in water.

Pond volume (m³) = length × width × mean depth; water mass (kg) = volume in litres × 1.0 (fresh water at field temperatures).

Feed ration as % body weight: daily feed (kg) = total biomass (kg) × ration % ÷ 100; biomass = number of fish × average weight.

Dissolved oxygen saturation falls as temperature and altitude rise; oxygen solubility in fresh water at 30 °C is about 7.5 mg/L versus about 9.1 mg/L at 20 °C at sea level.

pH is a negative logarithm scale: a fall from pH 8 to pH 6 means a 100-fold rise in hydrogen ion concentration.

Ammonia toxicity: un-ionized NH₃ fraction increases with pH and temperature; at pH 9 and 30 °C a far larger share of total ammonia is toxic NH₃ than at pH 7.

Growth and feed conversion: FCR = feed offered (kg) ÷ live weight gain (kg); lower FCR means more efficient conversion.

Specific growth rate (%/day) = 100 × (ln final weight − ln initial weight) ÷ number of days.

Hardness and alkalinity are expressed as mg/L CaCO₃ equivalent; multiplying mg/L of Ca²⁺ by 2.5 approximates its CaCO₃ equivalent.

Inland fisheries cover freshwater and brackish inland waters: rivers, reservoirs, tanks, ponds, lakes, beels and canals; aquaculture is the controlled rearing of aquatic organisms.

Culture systems by intensity: extensive (no supplemental feed, low stocking), semi-intensive (fertilizer plus some feed), intensive (formulated feed, aeration, high stocking), and super-intensive (raceways, cages, recirculation).

Monoculture is one species; polyculture is several compatible species stocked together to use different pond niches (surface, column, bottom, margins).

Composite fish culture in India typically combines catla (surface), rohu (column) and mrigal (bottom) with silver carp and grass carp to exploit all feeding niches.

Integrated aquaculture links fish culture with agriculture or livestock: poultry-fish, pig-fish, duck-fish and paddy-cum-fish systems recycle wastes as pond inputs.

Cage and pen culture confine fish in enclosed structures in an existing water body; cage culture depends entirely on artificial feed and high water exchange.

Recirculating aquaculture systems (RAS) reuse water after mechanical and biological filtration; they need less water but more energy and capital.

Capture fisheries depend on natural recruitment and are regulated by mesh size, closed seasons and gear restrictions; culture fisheries depend on stocking and management.

Fish classes: Chondrichthyes (cartilaginous, placoid scales, no swim bladder) and Osteichthyes (bony, cycloid or ctenoid scales, swim bladder usually present).

Fins: paired pectoral and pelvic fins and unpaired dorsal, anal and caudal fins; the caudal fin types are homocercal (symmetrical) and heterocercal (asymmetrical).

Scales: cycloid (smooth-edged, soft-rayed fish) and ctenoid (comb-edged, spiny-rayed fish); scale rings are used in age determination.

Gills: four pairs of gill arches bearing filaments and lamellae; counter-current blood-water flow maximises oxygen uptake.

Digestive tract of Indian major carps is a coiled intestine without a stomach; grass carp have a long intestine suited to herbivory.

Air-breathing organs occur in Channa (pharyngeal), Clarias (arborescent), Heteropneustes (air sacs) and Anabas (labyrinth), allowing survival in low-oxygen water.

Reproductive modes: oviparous (most fish), viviparous (e.g., Gambusia) and ovoviviparous; fecundity is the number of ripe eggs per female.

Taxonomic hierarchy: Kingdom, Phylum, Class, Order, Family, Genus, Species; scientific names are italicised, with the genus capitalised and the species in lower case.

Catla catla, Labeo rohita and Cirrhinus mrigala are the Indian major carps; Hypophthalmichthys molitrix (silver carp) and Ctenopharyngodon idella (grass carp) are exotic carps.

Pond types by purpose: nursery (0.05–0.1 ha), rearing (0.1–0.5 ha) and stocking or grow-out ponds (0.5–1.0 ha or more); depth 1.5–2.0 m at the deepest point.

Pond shape is rectangular with a length-to-width ratio of about 2:1 or 3:1; the long axis should follow the prevailing wind to aerate the surface.

A dike should have a top width of at least 1 m, side slopes of about 1.5:1 to 2:1, and freeboard of 0.3–0.5 m above the maximum water level.

Soil with 20–30% clay is suitable for pond construction; excessive sand causes seepage, and excessive clay causes turbidity and poor workability.

Soil pH below 5.5 indicates acidity requiring liming; agricultural lime (CaCO₃) is applied at 200–1,000 kg/ha depending on soil pH and texture.

Water quality targets for carp culture: pH 6.5–8.5, dissolved oxygen above 4 mg/L, total alkalinity 50–200 mg/L as CaCO₃, hardness 50–200 mg/L, and total ammonia below 1 mg/L.

Secchi disk transparency of 25–40 cm indicates adequate plankton; below 20 cm suggests dense algal bloom, and above 60 cm suggests poor fertility.

Fertilization (cow dung 5,000–10,000 kg/ha, or inorganic N and P) promotes phytoplankton; excessive fertilizer causes oxygen depletion at night.

Water temperature controls metabolism; Indian major carps grow best between 25 and 32 °C, and thermal stratification occurs in deep ponds during summer.

Induced breeding uses pituitary gland extract (PG) or synthetic hormones such as ovaprim, ovatide or HCG; a typical dose is 2–3 mg PG/kg for the first female dose and 5–8 mg/kg for the second.

Injection sites are intramuscular (near the dorsal fin base) or intraperitoneal; females receive two doses and males a single dose at about half the female dose.

Latency period between the final injection and spawning is about 6–8 hours for catla and rohu at 26–28 °C.

The Chinese circular hatchery uses a spawning pool, incubation/hatching pool and nursery pool; eggs hatch in about 16–24 hours at 26–30 °C.

Stripping collects eggs and milt by gentle abdominal pressure; fertilization is done dry by mixing eggs and milt, then adding water.

Nursery ponds are prepared by drying, liming (200–500 kg/ha), manuring and screening against predators and insects before stocking fry.

Fry are stocked at 3–5 million/ha in nursery ponds and reared for 2–3 weeks to fingerling stage; survival of 40–60% is typical.

Hypophysation depends on broodstock maturity; females with a soft, swollen abdomen and oozing vent and males with free-flowing milt are selected.

Transport of seed uses oxygen-packed polythene bags at about 1 part water to 2 parts oxygen, with density adjusted for fry size and journey time.

Crude protein needs: fry 35–40%, fingerlings 30–35%, grow-out carps 25–30%; energy content around 300–350 kcal digestible energy per 100 g feed.

Essential amino acids for fish include lysine, methionine, tryptophan, threonine and arginine; fish meal is rich in lysine and methionine.

Feed ingredients: rice bran and wheat bran as energy sources, groundnut or soybean meal as plant protein, fish meal as animal protein, and mineral and vitamin premixes.

Pearson square method balances two ingredients to a target protein: parts of A = (target − % protein of B) and parts of B = (% protein of A − target).

Feed ingredients should be ground and pelleted; sinking pellets suit carps, and floating pellets allow observation of feeding response.

Feeding rate falls with fish size: roughly 5–10% body weight per day for fry, 3–5% for fingerlings and 1–3% for grow-out fish.

Feed should be given at fixed times and places (usually 2–3 times daily); the daily ration is adjusted monthly by sampling and weighing fish.

FCR in carp polyculture with formulated feed is typically 1.5–2.0; excessive feeding raises FCR, wastes money and fouls water.

Anti-nutritional factors such as trypsin inhibitor in raw soybean and gossypol in cottonseed meal are reduced by proper heat processing.

Disease diagnosis follows history, water quality testing, gross clinical examination, skin and gill wet mounts, and confirmatory laboratory tests.

Bacterial diseases: Aeromonas hydrophila causes haemorrhagic septicaemia with red patches and ulcers; Edwardsiella and Pseudomonas cause similar signs.

Fungal disease: Saprolegnia appears as white cotton-wool tufts on skin and eggs, usually after injury or stress.

Parasitic infestations: Argulus (fish louse), Lernaea (anchor worm), Dactylogyrus on gills, and Ichthyophthirius multifiliis (white spot) are common.

Viral diseases of concern include Koi herpesvirus in carp and infectious pancreatic necrosis; viral infections do not respond to antibiotics.

Treatment examples: common salt 2–5% dip for external parasites, potassium permanganate 2–4 mg/L, formalin 25 mg/L, and lime for pond disinfection.

Biosecurity measures: quarantine new stock, screen inlet water, disinfect nets and equipment, restrict visitors, and dispose of dead fish away from ponds.

Stress from low oxygen, high ammonia, handling and overcrowding is the main trigger of disease outbreaks; correcting water quality is the first step.

Antibiotics should be used only on veterinary advice, with correct dose and withdrawal period, to limit resistance and residue problems.

Gear types: gill nets (entangling), cast nets (covering), seine nets (encircling), traps, hooks and lines; mesh size determines the size of fish caught.

Reservoir fisheries are classified as small (below 1,000 ha), medium (1,000–5,000 ha) and large (above 5,000 ha); stocking and fishing rights are managed by the state.

Reservoir yield depends on morphometry, nutrient status and fishing effort; pen and cage culture are used to boost production in large reservoirs.

Riverine fisheries depend on river flow, spawning migrations and connectivity; barrages and dams block migration and reduce recruitment.

Closed seasons protect spawning: a common closed season in Indian rivers is during the monsoon months, with restrictions on fishing in specified stretches.

Minimum legal mesh size allows immature fish to escape and spawn at least once before capture; destructive methods such as dynamite and poisons are prohibited.

Fish passes or fish ladders at barrages allow migratory fish such as Hilsa and mahseer to reach spawning grounds.

Beel and floodplain fisheries depend on seasonal flooding; connection between the beel and the river is essential for recruitment of wild seed.

Stock assessment uses catch per unit effort (CPUE), length-frequency analysis and mortality estimates to set sustainable harvest levels.

Harvesting methods: complete draining and netting, seine netting without draining, and selective harvesting by gill net; harvest in the cool early morning to reduce stress.

Fish spoil quickly because of high moisture, neutral pH and strong endogenous enzymes; rigor mortis sets in within hours and spoilage follows.

Preservation principles: reduce temperature (chilling, freezing), reduce water activity (drying, salting), exclude oxygen (canning, vacuum packing) or use preservatives.

Chilling in ice at a fish-to-ice ratio of about 1:1 holds fish near 0 °C; freezing at −18 °C or below preserves fish for months.

Spoilage indicators: trimethylamine (TMA) from bacterial reduction of TMAO, total volatile base nitrogen (TVBN) and histamine in scombroid fish.

Traditional products: sun-dried fish, salted fish, fish sauce, fish paste and smoked fish; value addition includes fish pickle, cutlets, fish protein concentrate and surimi.

Hygiene in handling: wash fish in clean water, use clean containers, avoid contact with the ground, and keep raw and processed products separate.

Quality standards in India are set by FSSAI and export inspection is governed by EIC; HACCP identifies critical control points in processing.

By-products: fish meal and oil from trimmings, fish silage, and chitin and chitosan from prawn shell waste.

Cost components: fixed costs (pond construction, pump, aerator) and variable costs (seed, feed, labour, lime, medicine); profit = total revenue − total cost.

Benefit-cost ratio = total benefits ÷ total costs; a ratio above 1 indicates a viable enterprise.

Break-even yield is the output at which total revenue equals total cost; break-even price = total cost ÷ total output.

Payback period = initial investment ÷ annual net profit; shorter payback means lower risk.

Marketing channels for fish include producer to consumer directly, producer to retailer, and producer to wholesaler to retailer; each intermediary reduces the producer's share.

Demand factors: freshness, species preference, price, season and festival demand; supply peaks during harvest season and depresses prices.

Entrepreneurship opportunities: seed hatcheries, feed mills, ornamental fish trade, fish processing units, cold chain and cage culture ventures.

Government support includes subsidies under the Pradhan Mantri Matsya Sampada Yojana, credit through NABARD and fisheries cooperatives.

Value addition raises margins; a fish pickle or dried product sells at a higher price per kg than fresh fish but needs packaging, branding and licensing.

Water quality field kit measurements: pH by pH meter or indicator paper, dissolved oxygen by Winkler titration, ammonia by nesslerization, and alkalinity by titration with H₂SO₄.

Secchi disk depth is read where the disk disappears from view; plankton is sampled with a plankton net and counted under a microscope using a Sedgwick-Rafter cell.

Fish length is measured as total length (snout to caudal tip) and standard length (snout to caudal base); weight is recorded on a balance to the nearest gram.

Age determination uses scale reading, otoliths or opercular bones; annuli are counted to estimate age and growth.

Gonadal maturity stages are assessed by macroscopic appearance of the ovary and testes and by the gonadosomatic index (GSI = gonad weight ÷ body weight × 100).

Project work follows the scientific method: state the objective, design treatments with replicates, record data in a logbook, analyse with mean and standard deviation, and interpret.

Soil testing in the field uses a pH meter on a soil-water suspension (1:2.5) and texture by the feel or sedimentation method.

Hatchery practical skills include broodstock selection, hormone preparation and injection, egg incubation and fry rearing.

Record keeping includes stocking records, daily feed and mortality logs, water quality registers and harvest accounts for economic analysis.

Water quality field kit measurements: pH by pH meter or indicator paper, dissolved oxygen by Winkler titration, ammonia by nesslerization, and alkalinity by titration with H₂SO₄.

Secchi disk depth is read where the disk disappears from view; plankton is sampled with a plankton net and counted under a microscope using a Sedgwick-Rafter cell.

Fish length is measured as total length (snout to caudal tip) and standard length (snout to caudal base); weight is recorded on a balance to the nearest gram.

Age determination uses scale reading, otoliths or opercular bones; annuli are counted to estimate age and growth.

Gonadal maturity stages are assessed by macroscopic appearance of the ovary and testes and by the gonadosomatic index (GSI = gonad weight ÷ body weight × 100).

Project work follows the scientific method: state the objective, design treatments with replicates, record data in a logbook, analyse with mean and standard deviation, and interpret.

Soil testing in the field uses a pH meter on a soil-water suspension (1:2.5) and texture by the feel or sedimentation method.

Hatchery practical skills include broodstock selection, hormone preparation and injection, egg incubation and fry rearing.

Record keeping includes stocking records, daily feed and mortality logs, water quality registers and harvest accounts for economic analysis.