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Apparently my fishing habits are altering the size of future fish, and not in a good way, according to a National Public Radio broadcast (January 16th 2009) on fishing and hunting.

Have you ever heard tales of epic battles with gigantic fish that took place many moons ago? Have you ever wondered why the largest fish that you ever caught you caught when you were a kid?

Apparently by catching and keeping big fish, we are all aiding the evolutionary process of natural selection that is leading to smaller fish. Why? Because we anglers who are fishing for dinner throw back the little guys and keep the larger ones. As a result, so says NPR, being small is a strategic advantage, and a characteristic that is transferable through generations.

As Jo Kettlewell writes in an article for the BBC:

“This evolutionary change could cause a whole host of problems for fish populations, such as decreased breeding rates and increased predation.

Fishing practices should preserve the natural genetic variation of fish populations rather than selecting only large individuals, say researchers, or we could see a severe decline in numbers.”

(Read full article here.)

A smaller fish future is confirmed by Canadian and Austrailian scientists in an article printed in the Scientific American:

“They find that fishing for the largest individuals targets the fastest growers, leaving behind their slower-growing counterparts. Which means that current fishing practices may favor the evolution of slower-growing fish.”

(Read the rest of the article and listen to the podcast here.)

What is the solution? As Jo Kettlewell suggests, one pragmatic fishing regulation that ought to be implemented is limiting the legal size of catchable fish to middle-sized fish. While this type of solution is quite practical for hook and line caught fish that can be easily thrown back (such limitations often exist for striped bass caught off the coast of certain states in New England), it isn´t so feasible to fish caught by industry boats trolling large nets.

Don’t fish? Well, apparently human aided evolution applies to game animals and plants as well!