Is it necessary to change?

It is amazing that such small things can make such a large impact on the environment around us. In an article featured on MSNBC.com, entitled Catch Large Fish, Encourage Small Fry, Randolph E. Schmid presents one such instance where little actions can be far reaching. Who knew that by encouraging fisherman to keep the larger fish they might be unnecessarily altering the variance of fish? By keeping the larger fish, fishermen are depleting the supply of stronger and somewhat more aggressive varieties of fish. This topic easily lends itself to the discussion of sustainability.

By taking the stronger fish we might be encouraging the growth in the population of fish that are not as strong and less likely to survive in larger numbers. Although it is fairly likely that each new generation of fish will have its stronger varieties, it is exceedingly less likely if the strong fish are always caught first. Schmid describes the circumstance as this:

“Biro and his colleague, John R. Post, stocked two lakes in western Canada with different types of rainbow trout- one type was known to be aggressive in seeking food and to grow rapidly, while the other grew more slowly and tended to take fewer risks in foraging. They set gillnets in the ponds over five day, moving them each day, and caught 50 percent of the stocked fast growing fish but just 30 percent of the more cautious ones.”

Although to many this does not seem like a big deal, but the fish that are more aggressive are the ones that will thrive and survive, whereas the fish that are not as strong will tend to show a less rapid rate of population growth. Even though it is a small matter it could have a somewhat large impact if the issue of sustainability is not taken into account. One might however ask, if this is such a big deal then why have we been taught to fish in this way for centuries, and never seen a significant impact? Is it really necessary to alter our behavior now?