Why are St Croix Sturgeon so skinny?

[DTro]

Compared to other bodies of water like the Rainy River. Is it forage? Is it environment? Slight different strain?

This is a question I ask myself every year and really have not been able to find a good answer. What I find odd is that there are some very fat fish as well in the Croix though too.

For example, here are some fat fish from this year, but probably the only 3 I can recall out of more than 100 caught though.

But overall, the norm is fish like this one:

In terms of length alone, the last picture is the longest we caught all year, but compared to fish caught up North weighed probably half as much. That fish was probably 30-35lbs and the same fish on Rainy would’ve been closer to 60.

So what does everyone think? What is the difference?

[Nick Kuhn]

Time of year might have something to do with it. I know the fattest pictures I see all come from the winter. It might also have to do with the size of the body of water. Most of those fish you catchy on the Rainy spend the rest of the year roaming LotW, where they probably aren't all that densely populated. Strain also probably has a little bit to do with it, but the upstream lake fish (which are likely the same strain) all see to be pretty fat. Without a doubt though Winnebago has the longest and fattest fish. I have no idea as to why.

[fishuhalik]

heres a couple of theories i came up with. i think between the mayflies and freshwater shrimp in lotw the sturgeon dont stop eating all year. also, lotw has a ton of ciscoe, and usually every lake has a pretty good dieoff of ciscoe every year. since theyre a really fatty/oilly fish, those big sturgies really pack on the pounds when theyre munching a couple of 1-3lb ciscoes every day during that dieoff. or maybe they just cruise around the big basin all year following pods of shiners and eat em as they die/get knocked out by gamefish. or its because they dont have to spend extra energy fighting current all day every day. im probably way off but thats all i could come up with.