Fish Genus: The Differences

Every multi-species angler knows that each fish species presents unique challenges and attributes despite their visual similarities. Despite this fact, there are many people who can not identify the numerous closely related species present in our states many waters which can lead to some embarrassing issues when it comes to taking count of the days catch. So lets clear the air, or water as it were, on this issue by pointing out the critical differences between species necessary for proper identification.

1): Walleye/Sauger:

Beyond fly fishermen,I'm almost certain that there is no person in the state that doesn't know what a walleye is. This species has become so big, both in popularity and actual size, in this state that teams from all over the country come to compete in our walleye tournaments. It is surprising then, that most homegrown weekend anglers cannot identify the difference between a walleye and its close cousin, the sauger. Now sure, some may not see it as that important a difference to make but in many of our rivers and reservoirs, Fort Peck included, there is a legal distinction made in the possession limits betwixt the two species, necessitating an understanding of their minute differences.

So what is the easiest way to identify the differences? When it comes to fish identification most people just look at a fish’s general color and give their verdict. Now sure that works with brightly colored aquarium fish from the equator but up here, where fish adapt to their environment by adjusting their coloration, it becomes much more difficult. For instance, someone once told me that the only way to tell a walleye and sauger apart was by their color. Walleye were always gold and sauger were always blue or grey. That was over eight years ago, and since then I have caught many more blue and grey walleye than I have gold. Why this is, I can only speculate, but it does go to say how wrong our assumptions can be.

Ok, ok. Enough waffling, time for the meat of the issue. Walleye can be easily identified by three factors; One, every walleye has a bright white tip on the bottom tip of its tail (on sauger this is a white line running the whole bottom margin of the tail); Two, On the spinney dorsal fin of each walleye there is a dark black spot between the last two or three spines (this is not present on a sauger, which has numerous small spots on the fin); and Three,  Walleye typically have a smooth coloration with and any with splotches resemble those of perch but are far less distinct (while splotches on a sauger are dark and randomly placed).

Follow these simple rules and you will be able to easily tell walleye and sauger apart. There is only one situation in which you will see an exception made and that is with hybrids, the mysterious “saugeye”. These fish throw a spanner in the whole works and more than likely require a geneticist to identify. So if you’re ever in doubt, throw it back. There are always more fish to catch.

2): Bass (Large and Small mouthed)

Now as I’m sure you can all imaging this is a topic close to my heart. However the state of Montana makes no difference between the species so it doesn’t really matter in any legal sense. But I don’t care! It’s important to me so now it’s important to you, deal with it. All joking aside though, properly identifying species of bass can help any angler refine their lure selection as each species seems to have its own unique preferences. But that is an article for another time.

So as we’ve established before, color isn’t the best way to identify fish species. Smallmouth are supposed to be brown and Largemouth are supposed to be green but I’ve seen that completely turned on its head before so who can say. If you really want an accurate way to identify the species, you can use these simple identifiers. One, on a largemouth the dorsal fin sections (you know, the spikey and not spikey fins on their backs) are barely touching if not completely separated where they are clearly connected on a smallmouth. Two, a largemouth’s jaw hinges behind its eyes (generally, if not directly below it) while a smallmouths hinges far forward of that. I know it seems obvious, but trust me, it matters. Three, the lateral line (a predominant sensory organ of fish, again an article for another day) on a largemouth is more often than not pronounced in the form of a dark black line or tight series of splotches down its flanks where a smallmouth’s is typically not visible in any form. 

3): PanFish

(Disclaimer: when I say ‘Panfish’ I am using it in the colloquial sense, meaning I am not limited to just the members of the Sunfish Family but am encompassing all small gamefish from across the state. Note the image above.)

In Montana there are many species of unique and colorful panfish. Each has their own unique niche that they fill while still remaining visually distinct. So I find it surprising when so many people fail to properly identify species from their visually similar cousins.

Bluegill vs. Pumpkinseed: The tiny cousins of the black bass are almost exactly similar in both size and appearance but there is one way to tell the difference. Now as much as I say color isn’t a way to identify fish species, this is the only possible vector in this case. Simply put, the Pumpkinseed is more colorful than the Bluegill. Now I know this is vague but I will try to be specific. A Bluegill has only one bright patch on its body which is a tab of iridescent blue on its gill plate while the Pumpkinseed is painted in a myriad of vibrant colors ranging from orange to blue. Seems simple but it is more difficult than most people think.

Black Crappie vs White Crappie: This is one of the strangest naming glitches in all of fishing. The Black Crappie (properly pronounced Craw-pee for those who insist on saying Krap-ee) is actually predominantly white with many dark splotches, while the White Crappie is more of a dark green. Strange? Yes. Clear? As crystal.

Yellow Perch vs Everything Else: This is by far the easiest distinction to make. While all of the previous specimens are members or close relatives of the Sunfish Family, Perch are actually of the (funny enough) Perch clan, relating closely to walleye, sauger and the European Zander. Meaning this fish is distinct because it looks like a walleye but colored green and yellow. Again, seems obvious but you don’t want to know how many misidentifications I heard involving this fish. It’s actually quite depressing.

Anyway, I hoped this has helped you and your fellow anglers out. Fish identification is important, if not for legal reasons then to make yourself look like a pompous arse when you have to put your knowledge in writing feel some sense of self-righteousness. J. Peace out and fish on.