Unit 4: Aquaculture - Environmental Impacts
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- Created by: rosieevie
- Created on: 25-05-15 14:03
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- Environmental Impacts
- Pollution
- Organic and Inorganic Waste - from surplus food, excretion and faeces and blood from processing plants
- Eutrophication and deoxygenation
- Increased primary production
- Changes in phytoplankton populations
- Increases in algal blooms - can be toxic
- Increased chemical oxygen demand
- Increased microbial activity
- Production of H2S and CH4
- Locate fish farms where currents dilute wastes
- Wastewater treatment
- Synchronised feeding times, optimised pellet size, color, texture and shape, even food distribution and exercise reduces food wastages
- CCTV beneath cages to monitor food wastage
- Pesticides - control weed and crustacean growth on cages and fish lice
- Use manual/ mechanical cleaning instead
- May be poisonous to wildlife
- Antibiotics - control infections
- Overuse can encourage antibiotic-resistant pathogens
- Reduced use using reduced stocking densities
- Organic and Inorganic Waste - from surplus food, excretion and faeces and blood from processing plants
- Habitat Impacts
- Overfishing - wild fish caught for farmed fish food
- May affect wild fish and predator numbers
- May also cause damage by the fishing methods
- Predator control - natural predators e.g. herons, otters may be culled if they become pests
- Use of better cages reduces this need
- Parasites - fish lice from densely populated cages may be passed to wild fish
- Wild fish more likely to suffer with infected wounds
- Less problematic with low stocking densities
- Gene Pool Contaminators - escaped farmed fish may breed with wild fish, altering gene pools
- Characteristics of selectively bred fish may be unsuitable for the wild
- Better designed cages mean fewer fish escape
- Introduced Species - escaped farm fish may compete with or become predators of indigenous species
- Habitat Loss - shrimp farms cause mangrove forest loss
- UK - Environmental Impact Assessments must be made before development occurs
- Overfishing - wild fish caught for farmed fish food
- Pollution
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