Maine Outdoor Journal
Nick Mills
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Streamside Darwinism?
Mar 2, 2009 01:23 PM
“They ain’t makin’ ‘em like they used to.”
That might be more than nostalgia, where fishing and hunting (but aren’t they the same thing?) are concerned . It might be evolution at work, on a fast track. An article from LiveScience.com reports evidence that because so many of the big ones didn’t get away, human predation has caused changes in the size and reproductive cycles of fish and animals. Examples include the drastically overfished Atlantic cod, which are mating a year earlier than they used to – at five years instead of six – and are smaller as adults, which also means that they produce fewer offspring. Alaska’s Kodiak bears, after years of selective trophy hunting which targeted the biggest animals, have gotten smaller. After decades of being killed for their ivory, some African elephant populations have unusually high numbers of tuskless animals.
The practice of trophy hunting is a form of selective breeding, according to one biologist cited, and is an express train to extinction.
When you look at the old photos of the monster trout being yanked from Maine lakes in the 19th Century, you have to wonder where those seven-and-eight-pound brookies are today? Nowhere, at least nowhere in Maine. There have been ecological changes, such as the introductions of competitive species, but a study published in the Proceedings of the National Academy of Sciences found that the changes in size and reproductive behavior are caused far faster by human predation than by changes brought about by pollution or the introduction of alien species. And this is just one study of many. The article cites 34 studies in 40 geographic systems, and the findings were consistent: ”Harvested and hunted populations are on average 20 percent smaller in body size than previous generations, and the age at which they reproduce is on average 25 percent earlier.”
Does this mean that when the Fish & Wildlife people set aside certain waters as trophy ponds, and allow only the biggest fish to be killed, they are inadvertently creating a smaller species of trout?
That might be more than nostalgia, where fishing and hunting (but aren’t they the same thing?) are concerned . It might be evolution at work, on a fast track. An article from LiveScience.com reports evidence that because so many of the big ones didn’t get away, human predation has caused changes in the size and reproductive cycles of fish and animals. Examples include the drastically overfished Atlantic cod, which are mating a year earlier than they used to – at five years instead of six – and are smaller as adults, which also means that they produce fewer offspring. Alaska’s Kodiak bears, after years of selective trophy hunting which targeted the biggest animals, have gotten smaller. After decades of being killed for their ivory, some African elephant populations have unusually high numbers of tuskless animals.
The practice of trophy hunting is a form of selective breeding, according to one biologist cited, and is an express train to extinction.
When you look at the old photos of the monster trout being yanked from Maine lakes in the 19th Century, you have to wonder where those seven-and-eight-pound brookies are today? Nowhere, at least nowhere in Maine. There have been ecological changes, such as the introductions of competitive species, but a study published in the Proceedings of the National Academy of Sciences found that the changes in size and reproductive behavior are caused far faster by human predation than by changes brought about by pollution or the introduction of alien species. And this is just one study of many. The article cites 34 studies in 40 geographic systems, and the findings were consistent: ”Harvested and hunted populations are on average 20 percent smaller in body size than previous generations, and the age at which they reproduce is on average 25 percent earlier.”
Does this mean that when the Fish & Wildlife people set aside certain waters as trophy ponds, and allow only the biggest fish to be killed, they are inadvertently creating a smaller species of trout?
Cruz says,
Nick,
Could you post a link to that article (National Academy) you mention with the citations? I'd really like to read more about this issue.
Thanks!
Mar 2, 2009 06:21 PM
frogge says,
Hey,
I think that less important than the reverse evolution issue, is the fact that the largest trout are usually females and will produce far more eggs than a smaller trout. Thus removing "trophies" removes the breeders that are most effectively going to support the population. If you must keep fish. Keeping smaller fish will impact the total reproduction less. In this age of digital photography and the ability of good taxidermists to make mounts from pictures, there is little excuse for keeping "trophies". Toodles,Frogge.
Mar 4, 2009 03:08 PM
JumpingJ says,
You should be ashamed.... Those fish are there you just have to look for them. Not as abundant, but those genetically beautiful trout are there, get off your lazy butt and find them.
Mar 4, 2009 08:47 PM
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