Harvesting large fish to promote lake productivity

[bwalt822]

I’m wondering if there is any information on what we can do as fishermen to promote a lakes productivity for good sized 12-14″ fish or something like that? My question was brought about by a situation my wife an I encountered the past few weeks.

Three or four weeks ago we made plans to visit a ~5 acre lake which based on the pattern for previous stockings was stocked every 4 or 5 years with 2016 or 2017 being the last likely year. I figured we would encounter small fish with maybe a large holdover or two if we were lucky.

When we got to the lake we saw many fingerlings too small to take a rooster tail for the most part. I had given up hope of a large fish until we got to the end of the lake and I saw a flash of something big near the bottom but was unable to catch it. We saw no medium sized fish and the fish were biting readily in other nearby lakes that day.

This got me thinking that one or two large holdovers could be eating the fresh plants and really decimate them over the winter or something. So we wanted to go back and catch it.

This past weekend our schedule and weather cooperated so we went back and were successful. My wife landed a fairly skinny 14″ fish and I caught a fat 16″ fish near where I had seen the flash before. My fish did have a fingerling in its stomach.

Given the size of the lake I doubt there were many more large fish as we were able to fish about half of it and the lighting was good to see into the water. Combined with the lack of medium sized fish, did keeping these two fish help future productivity?

Would that answer change if these were possibly breeding fish and of a different species than previous plants?

Many other lakes I’ve fished only had fish of similar size and weren’t breeding. I’m guessing taking limits of fish when the lake is full of 8″ fish wouldn’t be a good idea to promote good fishing in the future. But if a lake is recently planted do you want to make sure its cleaned out of large holdovers as much as possible?

• This topic was modified 7 years, 2 months ago by bwalt822.
• This topic was modified 7 years, 2 months ago by bwalt822.
• This topic was modified 7 years, 2 months ago by bwalt822.

[Brian Curtis]

The short answer is no, there is no advantage to keeping the larger fish. If you don’t keep them they will get even larger :-).

In reality, it is probably a bit more complicated then that. Some years plants don’t go as well as others and it isn’t always clear why. Perhaps they were stressed while being carried, or perhaps larger fish in the lake chow down on the fry. But the vast majority of the time the fry will find refuge from the larger fish and will grow just fine. When they are small they have a different diet then the larger fish in the lake so it won’t really help the smaller fish to remove the larger ones unless there are too many fish in the lake and this doesn’t sound like the scenario you encountered.

[bwalt822]

The fish we caught were actually brown trout but we didn’t know at the time that they could be considered “invasive” and the lake was not too far off I-90. Past plants were all rainbows. I read a few more older posts after making my OP and its possible they were planted illegally?

[Brian Curtis]

Yes, there have been a ton of brown trout planted illegally, especially in the I-90 corridor.

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