– How do they track fish population?

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– How do they track fish population?

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Here’s one way I remember hearing about:

You throw a net in, you get 20 fish, and tag them all. Then put them back. (This is how you would do it for lakes, I think)

Later, you cast your net, and again pick up 20 fish. If, for simple math example, you found half of that (10) to be tagged, you’re going to assume that the lake has 40 fish in it, because your sample leads you to believe that the fish you picked up before make up approximately half of the overall population.

Obviously multiple and larger samplings over more time will give you better data!

Depends specifically where you are tracking the fish, rivers, lakes or oceans.

Specifically the lake I’m near the DNR (department of natural resources) has this neat fishing boat that has this crazy contraption on it. It basically has a bunch of wires that dangle into the water and every once in a while they will electrocute the water which stuns the fish causing them to float. They float up and get counted by hand. The boat then moves on to another location of the lake and does it again.

[This](https://www.fergusfallsjournal.com/wp-content/uploads/2018/06/0619.dnr_.column-622×372.jpg) isn’t the exact style of boat they use, but might get the image across better.