Aquaculture Notes

Sources of Food

• Hunting-gathering
• Cultivated land plants
• Domesticated animals
• Aquaculture

Earth's Water Coverage

• Ocean hemisphere
• Land-ocean hemisphere
• Water covers 71% of the Earth

Fishing Techniques and Technologies

• Spotter airplane: Used for locating schools of fish.
• Fish farming in cage: Aquaculture method.
• Trawler fishing: Utilizes a trawl to catch fish.
  • Trawl flap.
  • Sonar: For detecting fish.
  • Trawl lines.
  • Trawl bag: Collects the fish.
• Purse-seine fishing.
• Long line fishing: Employs lines with hooks.
• Drift-net fishing: Fish are caught by their gills in the net.
  • Float buoy.
  • Fish school.
• Trawler Electronic fish finders.

Bycatch

• Unintended catch of non-target species.

Shift to Aquaculture

• Moving away from "hunting" to farming of fish.

Aquaculture Details

• Production of food from aquatic habitats
  • Freshwater
  • Marine = Mariculture
• Important source of protein in Asia and Europe.

Meat Production Efficiency

• Kilograms of grain needed per kilogram of body weight:
  • Beef cattle: 7
  • Pigs: 4
  • Chicken: 2.2
  • Fish (catfish or carp): 2

Omega-3 Fatty Acid Production

• Produces 50 tons of omega-3 fatty acid (2019).

Aquaculture Trade-offs: Advantages

• Highly efficient.
• High yield in small volume of water.
• Increased yields through cross- breeding and genetic engineering.
• Can reduce over- harvesting of conventional fisheries.
• Little use of fuel.
• Profit not tied to price of oil.
• High profits.

Aquaculture Trade-offs: Disadvantages

• Large inputs of land, feed, and water needed.
• Produces large and concentrated outputs of waste.
• Destroys mangrove forests.
• Increased grain production needed to feed some species.
• Fish can be killed by pesticide runoff from nearby cropland.
• Dense populations vulnerable to disease.
• Tanks too contaminated to use after about 5 years.