Propagating and Selling Fish!

Next Generation Science / Common Core Standards Addressed

• HS‐LS2‐6.Evaluate the claims, evidence, and reasoning that the complex interactions in eco systems maintain relatively consistent numbers and types of organisms in stable conditions, but changing conditions may result in a new ecosystem.

• HS‐LS4‐5. Evaluate the evidence supporting claims that changes in environmental conditions may result in: (1) increases in the number of individuals of some species, (2) the emergence of new species over time, and (3) the extinction of other species. [Clarification Statement: Emphasis is on determining cause and effect relationships for how changes to the environment such as deforestation, fishing, application of fertilizers, drought, flood, and the rate of change of the environment affect distribution or disappearance of traits in species.

Bell Work / Objectives

• Identify propagation methods of fish.

• Describe how to care for fry.

• Identify strategies for marketing fish.

• Identify factors that affect selling fish.

Terms

• Artificial spawning• Broodfish• Farm spawning• Fingerlings• Fry• Live haulers• Milt

• Mouthbrooders• Natural spawning• Photoperiod• Propagation• Spawning• Spawning container• Substrate spawning

Propagating and Selling Fish

• What product does a cattle rancher sell?

• What product does a hog farmer sell?

• What product does a fish farmer sell?

How are fish propagated?

• Propagation– Process of man controlling fish reproduction.

• Fish reproduce by spawning.– Female lays her eggs and then the male

deposits sperm over the eggs.

• Method’s of propagating fish vary by species.

Catfish propagating

• Often allowed to naturally spawn– Without the intervention of man.– Female seeks a hollow structure to lay eggs.

• Can use farm spawning– Occurs when male and female catfish are

moved to a spawning container.• Artificial nest

– Fertilized eggs can be left in pond or moved to hatchery.

– Eggs will hatch in 6 to 10 days.

Spawning Containers

Tilapia propagating

• Usually spawned in ponds, tanks or aquaria.

• Spawning controlled by photoperiod.– Number of hours of sunlight during a day.

• Spawn when days reach 10 to 16 hours.

• Spawning can be controlled by artificial lights.

Tilapia propagating

• Mouthbrooder– Lay eggs in

nest.– Allow eggs to

be fertilized.– Female will

incubate eggs in mouth until hatched.

• Substrate spawning– Lay eggs in

their nests on bottom of pond.

– Eggs are fertilized.

– Eggs remain on the bottom to hatch.

Trout propagating• Can spawn naturally but usually incubated

commercially.

• Trout eggs take 80 days to hatch.

• Often propagated by artificial spawning.– Eggs are removed from female.– Milt (sperm) is removed from male.– Humans mix the eggs and milt together.– Fertilized eggs placed in incubators.– Eggs are monitored and controlled.

How should fry be cared for?• Fry

– Immature fish

– Must be protected from predators in natural spawning.

– Dietary requirements are different than adult fish.

How should fry be cared for?

• Fingerlings– Young fish slightly

larger than human fingers.

– Ready to be stocked in ponds.

Catfish fry

• Born with an egg sac that gives nutrition for a few days.

• After egg sac is gone feed 49% protein feed that is finely ground.

• Protein percentage is reduced as fry matures.

• Fry kept in troughs or other protected areas for 1 year.

• Then they are considered fingerlings.

Tilapia fry• Cared for in similar way as catfish.• Started on feed that is as high as 60% protein.• Feed is usually ground into a fine meal or

pellets that disintegrate in water.

Trout fry

• Cared for similar to catfish and tilapia.

• Very small.

• After hatching moved to troughs.

• Fed a nutritious feed.

• Continuously graded to keep fry of similar size together.

• Done to prevent larger fry from eating the smaller ones.

What are some strategies for marketing fish?

• Sell broodfish to hatcheries– Fish used for breeding.

• Fish hatcheries– Produce eggs, fry and/or fingerlings sell

these to other producers.• Obtain eggs or fry from hatcheries.

– Raise them to fingerlings size.– Sell them to producers to stock ponds.

What are some strategies for marketing fish?

• Raise the fingerlings to harvest size.– Sell the fish to processors, fee lake

operators, or live haulers.

• Live haulers– Buy fish from growers and then resell to

fish markets or fee lakes.

What are some strategies for marketing fish?

• Fee lake operators– Obtain fish from

growers.– Stock ponds.– Charge people to

fish in their ponds.

What factors affect selling fish?

• Size of the fish– Should be marketed at optimum size.– Varies with species and stage they are

marketed.– Need uniform lots.– Separate fish by size.– Numerous mechanical devices can be used to

sort fish.

What factors affect selling fish?

• Grading Fish– Remove fish that

are diseased or injured.

– Graded on color.– Uniform looking lot

of fish is desirable.

Review / Summary

• How are fish propagated?

• How should fry be cared for?

• What are some strategies for marketing fish?

• What factors affect selling fish?

The End