Post By: malty falcon Posted: 5/16/2021 2:04:43 PMPoints: 7586
Caught a very stuffed laker last week, about 20”. We cut him open to see what was on his buffet. At first glance, we thought tiny crayfish. When I got home, I zoomed in, and couldn’t identify the bugs. Fish was in 60 FOW, and there was a decent school of lakers under us- we managed 3 doubles in 3 hours, and landed 16 lakers and 3 browns, before we went looking for bigger fish.
Reply by: Barnacles Posted: May. 17, 11:42:39 AM Points: 972
My eyes are bad, but looks like 3 different things in that sample to me. I think I'm sold on the scuds, but looks like two insect nymphs in there too. I'm glad I'm not the only one that digs things out of fish stomachs.
First off, I'll say that you have a very clean and good sample, less than 12 hours old. Otherwise, you'd probably have mush.
Second, I have not studied aquatic invertebrates, but have studied aquatic insects. Those are not insects. :)
To me, they do have the appearance of the aquatic sowbugs and scuds (or fairy shrimp). Typically more shallow, so my guess is that they were breakfast before the fish went deep again. It's not uncommon for lakers to display diel vertical migration, coming shallow to feed and going deep again to digest. Walleye do the same thing.
Aquatic invertebrates are typically what produce pink meat. When the meat starts turning white, is an indication that the fish is switching meals to more fish (becoming piscivorous).
It's good to know your quarry... including their last meal. :D
I caught 2 lakers yesterday and both were packed FULL of these guys, like, stomach stretched as far as it could go full. I didn't get a picture, but the front half of the stomach was full of freshly eaten ones and they were pretty clearly aquatic sowbugs.
They were concentrated at the edge of a 60 foot flat overlooking deeper water. There was loads of fish there, and they were tough to get to bite. Considering how fresh some of the ones in the stomach were, I thought they must have been feeding on them down there.
Most of that stomach doesn't look like mysis to me. Mysis are long and thin, and would be dang near transparent by the time you got them out of the stomach.
What I'm seeing are isopods, which is a big, diverse order of crustaceans whose best-known member is the rolly-polly (or pillbug or woodlouse or whatever other name you like) that you see in your backyard. Most isopods are marine, and include those bizarre tongue-eating fish parasites (google *that*, I dare you). Regardless, all isopods pretty much look like rolly-pollies, in that they're flat with hard armor plates on their backs. It's totally reasonable that lake trout would be eating these guys, isopods like to live on any sediment surface they can find, even in deep water.
A note on common names for small freshwater crustaceans:
Most anglers don't have any idea what an "isopod" is and generally lump these dudes in with other small aquatic crustaceans and call them all "scuds", "freshwater shrimp", "fairy shrimp", or some such other local name.
To me, "scuds" mean the amphipods, which are closely related to isopods but totally different in shape and habit. That can be important if you're trying to "match the hatch"! If you hear they're getting fish on "scuds", you better find out if they mean isopoda or amphipoda!
"Freshwater shrimp" is a common term that is typically used interchangably with "scud". I hate the term because "scuds" (amphiods/isopods) are not shrimp, and true freshwater shrimps are a totally different animal with totally different shape, color, and habit.
"Fairy shrimp" is typically a term for a totally different thing, and generally not important to anglers. When most folks say "fairy shrimp", they're referring to brine shrimp (sea monkeys), tadpole shrimp, or other weird crustaceans that live in temporary pools or hypersaline lakes.
Darn it. When Brookieflyfisher posts, I end up on google or immersed in textbooks for hours just to translate to redneck. My IQ is about 12, but the Isopoda order is under the subphylum crustacea. Them is some scuds.