lab practical (Perch)

Mouth

Captures and ingests food; also draws water into the oral cavity to be pumped across the gills for respiration.

Eyes

Large, lidless sensory organs positioned laterally to provide a wide field of vision for detecting prey and predators.

Lateral line system

A line of sensory organs running along each side of the body that detects vibrations, water currents, and pressure changes in the water.

Fins

Provide stability, propulsion, steering, and stopping; includes dorsal and anal fins (stability/anti-roll), caudal fin (forward motion/thrust), and pectoral and pelvic fins (steering/maneuvering).

Operculum

A protective, bony flap covering the gills that pumps water out of the gill chamber to assist with continuous respiration.

Gills

Feathery structures composed of filaments that perform gas exchange (absorbing dissolved oxygen from water and releasing carbon dioxide).

Heart

A two-chambered pump (one atrium, one ventricle) that receives deoxygenated blood from the body and pumps it forward to the gills for oxygenation.

Liver

Produces digestive fluids (bile), stores nutrients/glycogen, and detoxifies metabolic wastes in the blood.

Stomach

A J-shaped muscular organ that begins mechanical and chemical breakdown of swallowed food.

Intestine

Completes chemical digestion and absorbs nutrients into the bloodstream before passing waste toward the vent.

Vent

The external opening on the ventral surface that allows for the expulsion of digestive waste (feces), urine, and reproductive gametes.

Kidneys

Dark, elongated organs running along the dorsal body wall that filter metabolic waste and excess water from the blood to maintain osmotic balance.

Swim bladder

A gas-filled internal organ that controls buoyancy, allowing the fish to maintain or change its depth in the water column without sinking or floating.

Gonads

Primary reproductive organs—ovaries in females (producing eggs) or testes in males (producing sperm)—responsible for reproduction.