Lured out of the Gene Pool

A fascinating new study published in the Proceedings of the National Academy of Sciences suggests that the impact of human fishing may be reducing the fitness of fish populations overall. It may also explain why your grandfather insists that "the fish don't bite like they used to." The thinking goes like this: bold and aggressive fish tend to eat more, grow faster and ultimately have more baby fish. They also tend to be the ones that chase and bite fishing lures, and in the case of commercial fishing, get caught in gill nets.

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Aggressive, fast breeding fish are naturally attracted to huge lures.

The fish that do not go after lures and avoid the gill-nets tend to be those that are more timid. Typically, these timid, passive and slow-growing fish would lose out to their bossy, ill-tempered counterparts but in this case they are the only ones that breed. This creates an entire population of wimpy, loser fish. If only there were more software jobs for bass...

According to the study, fast-growing fish are harvested at three times the rate of the slow-growing genotypes within two replicate lake populations. Although the study was performed in freshwater, the University of Calgary researchers believe this might help explain the inability of the Atlantic Cod population to bounce back despite recent fishing reductions.

The study also explained why simply protecting the largest fish that presumably were jocks in high school, is not enough to protect the population "because fast-growing fish that are still small are zooming around gathering food at high rates which gets them into trouble."

For some additional info you can check out Mark Powell's post at blogfish.

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This sounds reasonable. There has been some work done by fisheries people on interspecies hybrids for farming, etc. There was a good bit of this work done at the Illinois Natural History Survey back in the 70's looking at hybrids among various sunfish species. The hybrids generally grew faster than the parent species and were much more catchable. I recall a comment that the hybrids behaved like one of the parent species with a particular brain lesion.

From memory, the INHS did an experiment where they stocked a park pond with 4000 hybrids and 3000 bluegill. Let them grow for a summer and had a fishing derby in the fall. All 4000 hybrids were caught before a single bluegill was caught. The two hybrids commonly available for your farm pond are green sunfish x bluegill, and redear sunfish x bluegill.

Google "meanmouth bass" for some interesting reading on black bass hybrids.

By Jim Thomerson (not verified) on 28 Feb 2008 #permalink

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