Unit 4: Aquaculture - Methods Used
- Created by: rosieevie
- Created on: 24-05-15 16:35
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- Methods Used In Aquaculture
- Monosex Culture
- Higher growth rates and less aggression
- Prevents gonad production so more energy used in growth
- Greater uniformity of size
- Extensive Aquaculture
- Relatively low inputs
- Oysters - 'spat' (young larvae) settle on specially cleared estuary beds. Spaced evenly with predators and competitors controlled and are harvested when large enough to eat
- Carp - predators controlled and nutrients added to stimulate the growth of the water weeds they eat
- Intensive Aquaculture
- High yield - all possible factors controlled
- Selective breeding to increase growth rate and enhance desirable characteristics
- No competitors and predators
- Pest and disease controlled by inoculation or pesticides and antibiotics
- Limiting abiotic factors controlled
- Artifical Breeding
- Induced ovulation - hatching times optimised
- Control of spawning via hormones, pheromones, optimum temperature and appropriate food and nesting sites
- Example - Salmon
- Fish with desirable characteristics stripped of eggs (roe) and milk (sperm)
- Sperm and roe mixed to allow fertilisation
- Fertilised eggs raised in freshwater aerated tanks with dead or diseased eggs removed daily
- Hatched fish moved through a series of tanks and fed on fishmeal pellets
- 12-18 months = 'smolts' - moved to seawater tanks until they are ready for harvest
- Monosex Culture
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