I caught this guy yesterday in Cook's Bay, and both species are well known from the area. First impression was a smallmouth, but now I'm having second thoughts. It fought a lot harder than the few largemouths I've caught, but never did any aerobatics. There are no stripes that I could see, horizontal or vertical. I wanted to get it back in the water, and I never thought of extending the dorsal fin in time. The mouth looks to end at the eye, not past and the eyes looked dark, not red. No overhead cover where it was caught, but lots of weeds. I'd guess about 10 feet of water. What do any of you seasoned veterans think?
That's a Largemouth, you can tell just by it's looks but if you want to delve deeper, you can see that it's mouth extends just slightly past its eye.
If you look carefully it does have the horizontal stripe that gives it away as a largemouth. It's most visible from the eye to the gills and becomes hazy on the torso but it's there.
Colour is tricky for ID sometimes...especially with pale fish. I've caught bass that, by colour alone, is so pale that you can't tell from one or the other. Largemouth that are quite bronze with not a single marking on the side or gill plate...or Smallmouth so gree you swear it was a Largemouth.
The simplest...and least confusing is the position of the rear edge of the maxillary. The maxillary is that triangular bone on the upper jaw which forms the corner of the mouth. This is the bone that keeps the hook very well when you hook the fish in the corner of the mouth. The white membrane you see in the picture connects this maxillary bone to the skull.
Now, look at the skull where this white membrane connects to the maxillary. Trace that edge to the corner of the mouth. See how the corner of the mouth goes way past the eye? This edge is where the maxillary fold up against the skull when the mouth is closed. So whether if the fish has the mouth closed (maxillary beyond the eye) or if the fish has the mouth open (maxillary forward but the edge where the membrane trace the skull is still beyond the eye), you can identify the fish as a Largemouth Bass.
Remember, the true corner of the mouth is where the maxillary meets the skull. Finding the membrane that connects the maxillary to the skull is the simplest way to find the corner of the mouth. It is not where the upper and lower jaw meets as you suggested in the picture.
Largemouth.
Scale texture in upper side of belly area also differs between the species. Largemouth has a slightly larger more coarse pattern here.
That's a baby largemouth.
Large but too small
