2 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.
3 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.
5 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?
6 How are fish propagated? PropagationProcess 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.
7 Catfish propagating Often allowed to naturally spawn Without the intervention of man.Female seeks a hollow structure to lay eggs.Can use farm spawningOccurs when male and female catfish are moved to a spawning container.Artificial nestFertilized eggs can be left in pond or moved to hatchery.Eggs will hatch in 6 to 10 days.
9 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.
10 Tilapia propagating Mouthbrooder Substrate spawning Lay eggs in nest. Allow eggs to be fertilized.Female will incubate eggs in mouth until hatched.Substrate spawningLay eggs in their nests on bottom of pond.Eggs are fertilized.Eggs remain on the bottom to hatch.
11 Trout propagatingCan 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.
13 How should fry be cared for? Immature fishMust be protected from predators in natural spawning.Dietary requirements are different than adult fish.
14 How should fry be cared for? FingerlingsYoung fish slightly larger than human fingers.Ready to be stocked in ponds.
15 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.
16 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.
17 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.
18 What are some strategies for marketing fish? Sell broodfish to hatcheriesFish used for breeding.Fish hatcheriesProduce 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.
19 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 haulersBuy fish from growers and then resell to fish markets or fee lakes.
20 What are some strategies for marketing fish? Fee lake operatorsObtain fish from growers.Stock ponds.Charge people to fish in their ponds.
21 What factors affect selling fish? Size of the fishShould 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.
22 What factors affect selling fish? Grading FishRemove fish that are diseased or injured.Graded on color.Uniform looking lot of fish is desirable.
23 Review / Summary How are fish propagated? How should fry be cared for? What are some strategies for marketing fish?What factors affect selling fish?