Monday, February 20, 2012

Aquaculture: Fish Farming in a Nutshell

Aquaculture is the farming of aquatic lifeforms for human consumption. It produces about half of all fish that is eaten worldwide.

As wild fish populations steadily decline, and fishery catch sizes continue to shrink, humans' unwavering demand for ocean produce has fuelled a large market for fish-farming.

Is it better to eat farmed fish than wild-caught fish? It is impossible to say for sure, but probably not. It's a complex issue. There are different types of fish farms, and different fish (or non-fish aquatic lifeforms) that are farmed, each requiring unique considerations.

In theory, fish farming could be a great alternative to fishing. In reality, it's kind of terrible.

SOME MAJOR CONCERNS

  1. Overcrowding
  2. Disease
  3. Waste products
  4. Escapes

ON-LAND FISH FARMS




Closed-system fish farms kept on-land are completely separate from ocean waters. While overcrowding (1) and disease (2) are still potential concerns, waste products (3) and escapes (4) have no environmental impact on the oceans.

OFF-SHORE FISH FARMS




Fish confined in nets located off-shore can potentially violate all the major concerns listed above. Overcrowding (1) actually contributes to the high incidence of disease (2) and toxic concentrations of waste products (3) such as ammonia, which adversely affect the immediate marine environment. Escaped farm fish (4) can spread disease to wild fish populations, and outcompete them for resources.

AT-SEA FISH FARMS




A free-floating fish farm—one that can be moved from one place to another in the ocean—is a good solution to highly concentrated waste products (3).

Overcrowding and escapes can be reduced in all fish farms, but that responsibility lies completely in the hands of the humans tending the farms. More fish in the pen may mean more money in the pocket, but at what cost?

UPDATE: I created a second post with handy-dandy infographics. Check it out.

Image Sources: (1 - Environmental Anthropology & Aquaculture) (2 - Green Report) (3 - National Geographic)

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