At least five species of snook are found in Florida and Texas waters.
Shown here with a dart tag, the Large Scale Fat Snook is the newcomer, that has recently been found in St.Lucie, Loxahatchee, and Sebastian Rivers.
Also known as the Mexican or Guianan Snook, its range was previously known as eastern Mexico to Brazil.
There may be 6 or 7 snook species eventually identified as genetic studies progress, according to Ron Taylor, senior biologist with FWRI.
Snook species vary greatly in maximum adult length and other characteristics.
All have a distinctive lateral line, but the shape of the head, the shape of the body, the size of scales, and the number of gill rakers are some of the variables that can help you tell them apart.
A key difference among snook species is the size of their scales. All fish, including snook, keep the same number of scales on their body no matter what their size.
The number of scales along the lateral line between head and tail is a characteristic of the species. Scales get bigger with age. The usual number of scales varies from 54 with the swordspine to 83 with the Fat. (You’ll notice one snook in the photo above has larger scales – that’s the species with the fewest)
The newcomer Large scale Fat Snook (mexicanus) can be distinguished from the small scale Fat Snook by the number of scales (83 on small scale vs 75 on large scale).
Body Shape and size characterize the five different species. Common Snook grows the largest, up to 48 inches, 44 lb, and has a more sloping forehead and protruding lower jaw.
The second-largest species, Small Scaled Fat Snook, has a fat, square body shape, and the anal spike may be short or long. The world record Fat Snook is just 10 lbs, and they seldom exceed 28 inches.
Tarpon snook looks a lot like tarpon: thin laterally, long head, upturned jaw, and the largest eyes of any snook species. Dark tips on ends of anal, ventral, and pectoral fins fade with age.
Swordspine Snook has relatively larger, shinier scales compared to other species, and is the only snook on which anal spike sometimes touches tail. It’s also the smallest, growing only to about 2 lbs.
The location of catch and habits of the fish help distinguish one species from another. For instance, adult common snook is often found in passes and along beaches, even on offshore reefs, while shyer Swordspine Snook is more often around docks and mangroves close to freshwater outlets.
Snook Species Characteristics
(C.undecimalis)largest snook species, up to 48 inches, 44 lblarger size, sloping fore-head, protruding lower jaw672-7311-12Tarpon
(C. pectinatus)usually < 3 lbtarpon-like: thin laterally, long head, upturned jaw, largest eyes of any snook species dark tips on ends of anal, ventral and pectoral fins fade with age76521-22Small Scaled Fat (C. parallelus)usually < 28 inches, 10 lb WRfat, square body shape, anal spike may be short or long 2nd largest snook species68315-16Swordspine (C. ensiferus)seldom > 1 lbrelatively larger, shinier scales compared to other species, only snook on which anal spike sometimes touches tail65418-19Large Scaled Fat
(C. mexicanus) Species recently found in Loxahatchee, St.Lucie & Sebastian rivers67515-16
Each species also has a distinct number of Gill Rakers, the white cartilaginous plates found behind the red gills. For instance, Tarpon Snook has the most of any snook species, 21-22 Gill Rakers.
One function of the Gill Rakers is to keep small prey from escaping through the snook’s gills when it closes its mouth.
So perhaps this says something about the size of prey that Tarpon Snook most often consumes, relative to the other species.
Another physical feature to help determine which species of snook are on the line is the Anal Spike and Anal Rays. In the common snook, there are 6 soft rays on an anal fin shorter than the anal spike.
In the tarpon snook, there are seven soft rays on the anal fin, not counting the first hard spike. The spike is always shorter than the longest soft ray.
Got a Puzzler? Use the guide above to recall the differences between species. Some individuals will vary in numbers of rays, scales, gill rakers– the numbers listed are norms.
When deciding whether to keep a snook remember all species are lumped under the same Florida fishing regulations governing snook size, bag, and season limits.
If you are stumped by your mystery snook, please, send us a photo, and if it’s a snook you consume, save the carcass in the freezer for later identification by otoliths and/or DNA.
Your data can add to the understanding of these fascinating fish!