Nature of Wild: Throwing the little ones back 

We value big things: big fish, big bucks, big racks. Given a choice, some hunters will wait for the largest buck or the bighorn sheep with the largest horns. Many fishing regulations have enshrined the idea that to improve the stock, we should throw the little ones back. In Michigan, for example, largemouth and smallmouth bass must be at least 14 inches in length to keep. Northern pike should be at least 24 inches in length to allow the fish to spawn before they are taken.

The theory is that we throw back the little ones so we end up with more big ones. Unfortunately, not all fish will grow to be big fish and not all deer will grow to be big deer. Some only have the genetic potential to be medium or small animals.

Dr. David O. Conover is Professor, Dean and Director of the Marine Science Research Center at Stony Brook University in New York. He observed that those tall tales about “the big one“ were true less and less frequently. He constructed a four-year-long experiment in which he placed 6,000 Atlantic silverside fish in tanks of 1,000 each and raised them through four generations in four years. Each year before spawning, he removed fish from each tank. In one tank, he removed 900 of the smallest fish. In another tank, he removed 900 of the largest fish. In the third tank, he randomly removed 900 fish. (Three of the tanks were controls.)

The results? At the end of four years, average size in the tank from which fish had been removed randomly had not changed. In the tank where small fish had been removed, the average size was longer. In the tank where big fish had been removed, the average fish was smaller.

This idea that humans have affected the course of evolution has been observed in nature, too. According to the University of California website (http://evolution.berkeley.edu/evolibrary/home.php), poaching of elephants for ivory has increased the frequency of tuskless elephants. Most populations of elephants include some that have no tusks, a hereditary condition. When poachers kill elephants for their tusks, they leave behind the tuskless to procreate and pass on their genes. This artificial selection increases the frequency of the “tuskless” gene in the gene pool.

Which raises the question:  can hunting and fishing regulations influence genetics?  We humans leave big footprints wherever we go. By hunting, or not hunting, by destroying or modifying habitat, by regulating or not regulating, we exert artificial selection, which changes the gene pool. While we often think we know what our impacts are, we sometimes—or maybe even often—don’t know. If we value wildlife, we should invest in research to help us understand our impact.

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