Post by bassgeek (Brock) on Jul 11, 2009 13:26:44 GMT -5
I just wanted to start a new thread on this subject. Shawn vtfishbio posted this information in an earlier thread, but it got burried. So rather than just bumping the thread, I thought I would start a new one. I find the information interesting.
Most anglers don't realize just how slow some fish species grow, and how many years it takes to attain some of these real trophy or quality sizes. Alot of the trout and salmon (with the exception of lake trout), can put many pounds and inches on in just a few years, while bass, walleye, pike and muskie take alot longer to get big.
Fish size and age relationships vary widely across locations, mostly latitudinally. A 4-pound smallmouth bass in Tennesee is much younger than a 4-pound smallmouth in the northern tier U.S. states or Canada.
For example, a 3 or a 4 year old smallmouth in Vermont would be around 12-inches in Vermont and would weigh less than a pound, whereas in some southern reservoir, it would be 4-pounds already.
In Vermont, a 4-pound smallmouth bass is a teenager, probably somewhere around 12-14 years old. A 20-inch, 5 pounder smallmouth could be nearly 20 years old. Largemouth are a little bigger for their age than smallmouths. A 4.5 to 5-lb largemouth bass is in it's high teens, and over 5-lbs it's like over 20 years old.
Here are a couple graphs from a size-age study on bass from Ontario, which is comparable to Vermont in terms of climate, growth parameters etc. Remember, these graphs can change from lake to lake, let alone from region to region, so use them only as a very basic guide to estimate size and age.
As for how many big bass would be in a fishery? Typically a fishery will be dominated by an abundance of younger fish, with fewer bigger, older individuals, because habitat and food supplies can't support too many huge individuals. Natural mortality weeds out and thins the smaller, younger fish, and only a small percentage ever reach those large proportions. For a typical fish population, an age-frequency graph illustrates this, and you'll see a graph that is skewed to the left, which are your younger, smaller fish. The graph below is another generic example from a bass population, showing what percentage of the population is made up of different aged individuals.
The bottom line is that big bass in Vermont are typically much older than people think, and when one is removed from the population, it takes a while to replace them as others grow into that size range. With a healthy population, there should be plenty of younger individuals ready to "recruit" or move into that vacated space and use the available resources to become larger and older, but it does take time.
Hope that helps.
Shawn
Fish size and age relationships vary widely across locations, mostly latitudinally. A 4-pound smallmouth bass in Tennesee is much younger than a 4-pound smallmouth in the northern tier U.S. states or Canada.
For example, a 3 or a 4 year old smallmouth in Vermont would be around 12-inches in Vermont and would weigh less than a pound, whereas in some southern reservoir, it would be 4-pounds already.
In Vermont, a 4-pound smallmouth bass is a teenager, probably somewhere around 12-14 years old. A 20-inch, 5 pounder smallmouth could be nearly 20 years old. Largemouth are a little bigger for their age than smallmouths. A 4.5 to 5-lb largemouth bass is in it's high teens, and over 5-lbs it's like over 20 years old.
Here are a couple graphs from a size-age study on bass from Ontario, which is comparable to Vermont in terms of climate, growth parameters etc. Remember, these graphs can change from lake to lake, let alone from region to region, so use them only as a very basic guide to estimate size and age.
As for how many big bass would be in a fishery? Typically a fishery will be dominated by an abundance of younger fish, with fewer bigger, older individuals, because habitat and food supplies can't support too many huge individuals. Natural mortality weeds out and thins the smaller, younger fish, and only a small percentage ever reach those large proportions. For a typical fish population, an age-frequency graph illustrates this, and you'll see a graph that is skewed to the left, which are your younger, smaller fish. The graph below is another generic example from a bass population, showing what percentage of the population is made up of different aged individuals.
The bottom line is that big bass in Vermont are typically much older than people think, and when one is removed from the population, it takes a while to replace them as others grow into that size range. With a healthy population, there should be plenty of younger individuals ready to "recruit" or move into that vacated space and use the available resources to become larger and older, but it does take time.
Hope that helps.
Shawn
