Maharashtra HSC Vocational Fisheries Technology key terms

A rapid, dense multiplication of microscopic algae or other drifting organisms in pond water, often turning it green or brown and affecting oxygen and light levels.

The amount of oxygen gas present in water and available to fish for breathing, measured in milligrams per litre and usually lowest just before dawn.

A flat white-and-black disc lowered into water until it disappears from view, giving a simple reading of water clarity and plankton density.

Applying calcium carbonate or similar material to pond soil or water to raise alkalinity, stabilise pH and improve conditions for fish growth.

Adding organic or inorganic nutrients to a pond so that natural plankton food organisms multiply, supporting fish without costly supplementary feed.

Mechanical or natural mixing of pond water with air to increase dissolved oxygen, especially during night hours or after heavy feeding.

Harm caused when un-ionised ammonia from fish waste and decaying feed builds up in water, damaging gills and reducing appetite and growth.

Removing part of the pond water and replacing it with fresh water to dilute wastes, lower ammonia and restore suitable conditions for stock.

A small, well-prepared pond used to rear fish fry or spawn for a few weeks until they are large enough to stock in grow-out ponds.

Very young fish shortly after yolk absorption, small and fragile, requiring careful handling, fine feed and predator-free nursery water.

A juvenile fish about finger length, produced after nursery rearing and used for stocking grow-out ponds because it survives better than fry.

The number of fish placed per unit area or volume of water, chosen to balance growth, survival, feeding cost and water quality.

Rearing several fish species with different feeding habits together in one pond so that food at all levels is used efficiently.

Farming two or more compatible aquatic species in the same water body to improve total yield and reduce waste build-up.

Triggering fish to spawn outside their natural season by injecting hormones or pituitary extract, allowing planned seed production.

Induced breeding by injecting pituitary gland extract, commonly from a donor fish, into brood fish to stimulate egg release.

A facility where brood fish are kept and spawned and eggs or larvae are reared under controlled conditions until they can be stocked.

A bony projection on the gill arch that strains food or plankton from water passing through the gills, differing in shape among species.

A thin structure on the gill arch richly supplied with blood vessels, where oxygen is taken up and carbon dioxide released.

The bony flap covering the gills on each side of a fish's head, protecting the delicate gill filaments and helping pump water.

An internal gas-filled sac that lets a fish adjust its buoyancy so it can stay at a chosen depth without constant swimming effort.

A row of small sense organs along a fish's side that detects water movement and pressure changes, helping in schooling and prey detection.

A small stony structure in the inner ear of a fish used for balance and hearing; its growth rings help estimate age.

A thin bony or horny plate covering fish skin, giving protection and reducing friction; its rings can indicate age and growth.

A wall of netting set vertically in water in which fish become entangled or caught by the gills when swimming into it.

A round net thrown by hand so it opens and sinks over a school of fish, then is hauled back with the catch trapped inside.

The distance between adjacent knots or bars in netting, which determines which sizes of fish are retained and which escape.

A cone-shaped net towed through water behind a boat, with its wide mouth held open to sweep fish into the narrow cod end.

Fish and other animals caught accidentally while targeting a different species, often undersized or unwanted and usually discarded.

Cooling freshly caught fish with crushed or flake ice to slow bacterial growth and enzyme action, preserving quality during transport and sale.

The stiffening of fish muscle after death as energy stores run out; handling during this stage can bruise flesh and lower quality.

An unbroken sequence of chilled storage and transport from harvest to consumer that keeps fish at safe low temperatures throughout.

Processing raw fish into products such as fillets, pickles, dried snacks or canned items to raise selling price and reduce spoilage losses.

The level of production or sales at which total revenue equals total cost, so the enterprise neither makes a profit nor a loss.

Total sales revenue minus the direct variable costs of producing the fish, showing how much is left to cover fixed costs.

Money needed for day-to-day running of a fish farm, such as feed, seed, fuel and wages, before sales income arrives.

A small group of villagers, often women, who save regularly together and lend to members, sometimes linking to bank or scheme finance.

A field officer who carries new aquaculture practices and government information to fish farmers and brings their problems back to researchers.

A pond managed to show proven practices to visiting farmers, letting them see results and learn techniques by observation rather than lecture.