All fish species have different external characteristics that make them who and what they are. Many species of fish exibit remarkable variation in physical shape within a single species, like the smallmouth yellowfish, in which mouth shape varies considerably according to the fish`s individual food preferance and habitat. Other families of fish have two or more species that can barely be told apart by external characteristics, for example the dusky cob and its nearly identical cousin, the silver cob.

While the good old fisherman`s story has its own very important place in the pursuit of angling, your average honest fly fisherman enjoys being able to at least accurately relate the species of fish that he caught. Trout fisherman in South Africa have it quite easy in this regard. Even though enormous variation occurs within both species, trout are very well covered in fly fishing literature, and the differences between browns and rainbows quickly become quite obvious at first glance.\par
Black bass, on the other hand, sometimes present anglers with a bit more of a challenge, in that the similarities between largemouth and smallmouth bass are often too many to make an accurate identification. In this article I aim to illuminate the unique external characteristics of these two species, and in so doing eliminate the confusion. If I may..

FIRST, THE OBVIOUS

Of the eight known species of black bass, largemouth and smallmouth bass are by far the most successful. While it is true that the largemouth bass sports the largest jaws of them all, the rest of the family have very similar jaw dimensions. And none of these fish, including the smallmouth, can really be accused of having small mouths at all. This is probably the main reason that smallmouth bass are sometimes mistaken for largemouths. The size of the entire head can at times be used to help tell the two apart, since smallmouths more often than not have smaller heads in relation to their body, than largemouths. This is, however, variable with the condition of the fish. Ill fed or stunted smallmouths will have bigger heads than normal, and the opposite is sometimes true for largemouths, especially in riverine habitats. How can looking at the size of the jaws help an angler identify his catch, though? Look at the close-up below:

With its mouth closed, the jaw-line of a smallmouth (pictured on the left) ends near the middle of the eye, and never further, while in the largemouth (picture right) it extends at least to the end of the eye, and sometimes a bit more.

THE FINS

Fins are vulnerable appendages. They`re often worn and torn, and for this reason one of the more effective ways to ID your bass is often lost. If however your fish has been looking after his fins, you will be able to spot another identifying characteristic. Least conspicuous, perhaps, is the fact that the soft rayed portions of the fins are larger in smallmouths than in largemouths. This is especially true in bigger fish, and is most pronounced in the dorsal and caudal fins. This is rather relative, though, especially if you`re not looking at both species at once. The area where the spiny and soft rayed portions of the dorsal fins meet, however, show obvious differences between the species. Smallmouth show a shallow notch between the two sections, and the fins appear as one. In largemouths the two sections are clearly separated by a deeper notch, as illustrated in the picture below. Again, smallmouth on the left, largemouth on the right:

COLOUR

As mentioned, many fish show physical variations within the species. In terms of colour, black bass are no exception. Smallmouth bass are often referred to as Bronzebacks, or brown bass, while the largemouth, I guess for want of a better nickname, are sometimes called greenies. Now, even though these handles more often than not hold true for both species, I have caught enough green smallmouth, and one or two brown largies, to know that this can also lead to some confusion. It is better to look at the colour pattern, rather than the shade. All black bass show three stripes radiating from behind the eyes, fading to the edge of the gill plates. Largemouth bass have a dark, most often broken horizontal line running from behind the head to the base of the tailfin. This line separates the darker dorsal area from the lighter coloured belly. Smallmouths, on the other hand, have long vertical bars on their sides. These are often only slightly darker than the background shade which fades more gradually from dark on the back to a lighter shade on the belly. Smallmouths more often than not have greyish bellies, while the belly of the largemouth is creamy white, and sometimes yellow in tannin stained waters. Using these characteristics to identify your fish is effective, but only until you catch a bass that does not seem to show any of the characteristic markings, except maybe for the radial eye stripes, like this eighteen inch smallmouth:

This apparent lack of markings is very common in both species. It is most often seen in fish that spend a lot of time in deeper or murkier water. Largemouth bass from muddy waters can become so pale that they almost appear silvery. This is not a permanent condition, though. If the fish were to move to clearer, shallower waters, their inherant colour patterns soon become visible again. Even though the smallmouths will always have vertical stripes, and largemouths will always have the single horizontal line, each fish`s stripes, like many other creatures in nature, are as unique as our own fingerprints. This modest largie is very brightly coloured, and clearly shows the broken horizontal line typical of the species:

DOES SIZE MATTER?

Most species of black bass have basically the same potential for growth. On average, black bass reach their maximum size at about three kilograms. Fish of this size are few and far between, though, and in most locations you earn bragging rights if you catch a fish of between one and a half and two kilos. The size any fish will reach is influenced by a great variety of factors, such as availability of food and the fish`s ability to catch it, the size of the population, the speed of the current it lives in and the actual size of the body of water it makes its home. Largemouth bass, generally, are stillwater fish, living in big impoundments with little current and plenty of food. This is the major reason for largemouth on average growing substantially larger than smallmouths. Because of the largemouth`s preferance for using ambush tactics to take prey, and the fact that they don`t have to fight heavy currents in their day to day existence, they invest most of their energy in growing for most of the year, the obvious exception being the spawn in spring. Smallmouth bass, by comparison, are evolved for a riverine environment. Also, they are less inclined to settle into ambush positions while hunting, and often travel good distances actively searching for food. This, coupled with the relatively strong currents (compared to largemouths) that they prefer to make their home, means that their average day to day existence is much more energy expensive, and thus less energy is invested in growth.

Now, there is an obvious exception in terms of size that bears mentioning. While most bass do peak at about three kilos in size, there is a common strain of largemouth native to Florida, which exceeds these limits quite dramatically. It is called, strangely enough, the Florida bass, and was introduced to South African waters along with the smaller Northern largemouth. The two strains of largemouth can`t be told apart by external features alone, but once you`re catching largies, or any bass for that matter, of 4 kilos and over, you can be pretty sure that they`re Florida largemouths.

The differences in growth potential is most clearly demonstrated by looking at angling records. These show that the biggest largemouth yet taken in South African waters is a fish that at the time of capture weighed 6,3 kilograms. It was taken in the Midmar dam in January 2007. This fish was a Florida bass, as was the world record largie which weighed over 10 kilograms. The Clanwilliam Dam in the Western Cape produces world-class smallmouth bass. The current South African record was caught here in August 2007, and tipped the scales at a fantastic 3,45 kilograms. IGFA currently recognises a five kilogram fish taken in the 1950`s as the world record smallmouth, but some say that this fish was not a smallmouth bass at all. It is, however clear that both smallmouth and largemouth bass can exceed their normal growth potential, so size alone is not a reliable way to identify your catch.

So is there a single physical characteristic that can be used to positively identify your catch every time, under all circumstances? Thankfully, there is. Check this out..

THE CLINCHER

The fact is, once you can recognise the most often overlooked, and yet the most distinctive physical difference between bronzebacks and their flabby cousins, you can forever ignore every one of the traits outlined above. The next time you catch a bass, have a close look at his gill plates. If the scales on the cheeks are only slightly smaller than those on the rest of the body, you have in your hands a largemouth bass. Simple as that. If however, the fish has much finer scales on the cheeks, and shows no sign of a single dark lateral stripe, it is a smallie. The example below, again with the smallie on the top and the largemouth on the bottom, shows the different sizes of said scales:

And that`s it. Simple as that. The more you catch of both species, the clearer the differences become. You will even start noticing that, especially in rivers, you won`t often catch both species in the same kind of water, or off the same kind of structure.

THE THIRD WHEEL

Every rule has an exception. If one day you find that the fish you pulled out of the water has both a dark lateral stripe and fine scales on the cheeks, then you have caught a spotted bass, the third and apparently least successful of the black bass species introduced into South African waters. This is only likely to happen in very few locations in this country, though, like the Olifants River system in the Cedarberg. To be absolutely sure, you can check the fish`s tongue for teeth. The spotted bass is the only one that has a patch of raspy teeth on the tongue. In the other two species, the tongue is smooth, and only the jaws are lined with these raspy teeth. It is normally easy enough to identify a spottie as a bass with the colour pattern of a largemouth, and the shape and fins of a smallmouth. It`s belly is usually whiter than that of your average largemouth, and the lateral stripe darker. In build they are nearly identical to smallmouth.

So here is a recipe for quick identification of the black bass species in South Africa: Big scales on the cheeks equals largemouth bass. Fine cheek scales and a smooth tongue equals smallmouth bass, and fine cheek scales plus teeth on the tongue and the colour of a largemouth equals spotted bass.

I hope that this article has helped to solve the mystery for those who have had trouble identifying the bass they caught in the past, and that it will be a little easier in successful trips to come. All that is left now is to go out and catch them. Tight lines!