Saturday, February 02, 2013

Four Fish

I didn't realize how much of fish in the world is now "farmed". This book takes us through the history of 4 fish that find their way to our dinner table. Salmon is first. Atlantic salmon is almost entirely farmed these days. In the past, however, salmon were abundant. However, dams destroyed their breeding grounds, and overfishing eliminated many of the survivors. Hatcheries attempted to replace some of the lost, but that backfired due to putting the wrong fish in the wrong area. There are a lot of different types of salmon, and this diversity has helped them to survive. Alas, man's intervention was too much. Many salmon have now been domesticated for human use. The initial approach was a monoculture with much waste. (And it takes 3 pounds of fish to make one pound of salmon.) However, some polycultures are being develop that use other animals, such as seaweed and mussels to provide food and consume the waste products.

Sea bass have also been "domesticated", even though they seem to fail every criteria that would make for a good domesticated fish. But, they are popular, so they were used. The Bass taxonomy seems to be based on appearance and "edibility", with most of the edible fish classified together. Bass have usually been a high value "holiday" fish, thus there was incentive to produce them in captivity. Many genetic discoveries were needed to be able to do it.

Cod are the third fish. They were an "everyday" fish known for their abundance. Alas, over-fishing has lead to the collapse of their fishery also. Attempts have been made to raise them in an organic, environmentally friendly manner - however, the fish didn't taste good and were too expensive. (You don't market a big mac as a luxury item!)

Other fish have been attempted to be raised in captivity. Some, like the Asian sea-bass were well suited for it. There were also a multitude of freshwater fish that are used for farming. Many of these require very little effort to farm successfully. Some, such as talapia can spread rapidly, and are a concern for other fish species.

The fourth fish is Tuna. Tuna can be very large and have become popular for sushi. Alas, this has lead to massive over-fishing, and made life dangerous for them. Some attempts to counter this, such as "tuna ranching", simple harvest fish when they are young - doing nothing to help the eventual breeding stock.

The "domestication" of fish is a relatively recent trend. Alas, we still don't fully understand the consequences. Northern Hemisphere farmed salmon have hurt the wild salmon when they escape and bread. Southern hemisphere salmon don't have this problem. However, they create other environmental issues. Farmed fish consume less feed per pound of meat than land animals. However, the interaction with other "wild" fish can still have negative impacts on some of the last commonly "hunted" animals. Fish also tend to cross multiple boundaries making it difficult to reach a governmental consensus. (And you often get the "late to the game" countries complaining that they didn't get as much as the people that have wiped out the population.) In the case of some animals, like whales, the public perception has shifted so that they are viewed as "wildlife" rather than "meat". Can animals exist as both? (I see that with our pet chickens. Once we got them, our kids wont touch chicken meat. The chickens, however, have no problem eating chicken nuggets.)

What will the fate of wild fish be? Will they eventually be run out of existence, similar to other ancient terrestrial mammals? Or will they become domesticated to the extent that they are optimized for meat volume at the expense of well-being and nutrition? Or will we actually reach a healthy middle ground? We will see.

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