In drawdown lakes or most any typical lake, crayfish generally live in water that’s 10-12 feet deep or less. On most lakes, they’re going to be in that opportune depth range. In clearer lakes, they may exist deeper as well, down to 20-30 feet.
In anticipation of winter coming, crayfish start to move into areas where they can burrow, and usually that starts around the drawdown.
When I say crayfish move, it’s not up or down. It’s sideways. They’re moving from a harder bottom to a softer bottom. Typically, they’re not changing depths, although survival instinct may tell them to go a little bit deeper if the water level falls too quickly.
The kind of move they make can be from sand to clay, sand to silt, from rock to clay – from a hard bottom, including sand in the category of a hard bottom to a softer bottom where they can build a winter home that will last till spring without collapsing in on them.
In the south, it can be water temperatures around 70 degrees when crayfish start to move. The farther south you go, the more it’s going to be like around 70, maybe even 75 when the crayfish start to migrate from summer feeding to winter burrowing locations. Once you get so far south, it just doesn’t happen. The farther south you go, the less likely the crayfish are to burrow and go dormant, just like the largemouth. The more likely they are to stay out year round. For example in Florida, Lake Okeechobee, there are crayfish that probably don’t burrow at all just because it stays warm most of the year. As you get way south, that whole low metabolism/hibernation phase of winter gets skipped.
In the north, water temperatures around 65 to 60 trigger the crayfish movement. At the extreme north range, those crayfish being totally different species, probably don’t burrow at all because they’re more of a year-round rock-dwelling species. A lot of it is they’re just selective to the different environments. There’s just not a lot of clay for them to burrow on rocky lakes up north. The farther north you go, the less softer bottoms there are, and the more rock there is in general. So there are more rock-dwelling species of crayfish that stay out year-round.They don’t have a lot of clay to burrow in like the other clay-dwelling species.
Where we see the most variety of clay-dwelling crayfish is in the middle belt where you have an overlapping ranges of different clay-burrowing species – Missouri, northern Alabama, Mississippi, Georgia, SC, NC, that whole belt right through there we see a lot more diversity of crayfish species. The clay-dwellers are usually like a reddish or a black/red shad color or a brown/orange pumpkin because they are clay-dwelling and burrowing species, but up north, those color crayfish are less likely to be common. Green pumpkin or dark browns are more common crayfish color up north. Up north the gold shiners and alewives are present. Down south, gizzard shad. That’s how the forage changes just going north and south.
It’s more than just temperature that triggers the crayfish move, but a combination of the tilt of the earth toward the sun and the length of day, as the days get shorter. The most obvious indicator or gauge we have of the days’ shortening is water temperature because as the day gets shorter, there is less UV and less sun hitting the lake heating the water, so it doesn’t stay heated up as long as in summer. It doesn’t have that retained higher temperature. So the dropping of water temperature is a reflection of the shortening of the day. Factor that with a lake that may have draw down, these are all indicators to crayfish that the time of winter is coming closer and that’s when they’ll be triggered to move. Again, it could be closer to 60 degrees up north when the crayfish start to trigger to move, around 65 degrees through the middle of the country, and say 70 at the southern end.
Across the entire country, we’re mostly talking of a falling water temperature from 70 to 60, give or take a few degrees, that triggers the crayfish move.