Sauger

The sauger's habitat is the clearest way to understand the fish, because it is defined against its better-known relative at every point.

SAUGER ARE FISH OF LARGE, TURBID, FLOWING RIVERS. Walleye are fish of clear lakes and reservoirs. Where the two overlap, sauger occupy the moving, coloured, sediment-laden water and walleye the clearer and stiller parts of the same system.

THE EYE EXPLAINS IT. Both species carry a tapetum lucidum — a reflective layer behind the retina — that makes the eye highly efficient in dim light. Sauger's tolerance of turbidity goes further than walleye's, which means a sauger can hunt in water where its prey is effectively blind and where a walleye would be at less of an advantage.

SO THEY ARE FOUND IN MAIN RIVER CHANNELS, in deep holes, over sand and rubble bottom, and above all in TAILWATERS — the turbulent, oxygenated, food-rich water immediately below a dam. Tailwater fisheries are the classic sauger location and are where most of the recreational catch comes from.

THEY MIGRATE LONG DISTANCES TO SPAWN, ascending rivers in early spring to reach gravel and rubble shoals. In a large unobstructed system those migrations can cover a very long way.

WHICH MAKES IMPOUNDMENT A DOUBLE PROBLEM. A dam blocks the migration, and it also converts the river above it into a lake — which is to say, it converts sauger habitat into walleye habitat. Sauger populations have contracted in impounded stretches across their range while walleye have gained, and the two facts are the same fact.

THE PRACTICAL CONSEQUENCE FOR AN ANGLER is that sauger are found by looking for the water walleye anglers ignore: coloured, moving, below a dam, and often in the cold months.

Sauger size is the character that most often causes a misidentification, because the fish is smaller than a walleye at every age and a large sauger looks like an ordinary walleye.

A TYPICAL SAUGER IS 30 TO 40 CENTIMETRES AND 300 GRAMS TO A KILOGRAM. Over 1.5 kilograms and 45 centimetres is a good fish in most waters.

REPORTED MAXIMA ARE AROUND 76 CENTIMETRES AND FOUR KILOGRAMS, and fish approaching that should be checked carefully against walleye and against saugeye before being claimed — the hybrid is intermediate in exactly the characters used to separate the parents, and it is stocked deliberately in some fisheries as well as occurring naturally.

GROWTH IS SLOWER AND ULTIMATE SIZE SMALLER THAN WALLEYE in the same system. That asymmetry is why the misidentification runs one way: a large sauger gets recorded as a modest walleye far more often than the reverse.

THEY ARE MODERATELY LONG-LIVED, maturing at two to four years and reaching well beyond ten in northern populations. Large sauger are therefore old sauger, and in heavily fished tailwaters the large fish are the ones a fishery has left rather than the ones it produces quickly.

WHICH BEARS ON MANAGEMENT AND ON RETENTION. Sauger and walleye are frequently managed under different size and bag rules in the same water, precisely because they grow differently — and an angler who cannot separate the two cannot comply with rules that treat them separately. That is the practical reason the identification matters, quite apart from the satisfaction of knowing what you caught.

Sauger run to a calendar that puts the best fishing at the times most anglers have stopped, which is a large part of why the species is undervalued.

SPAWNING IS IN EARLY SPRING, on an upstream migration to gravel and rubble shoals in current. Eggs are broadcast rather than guarded. In big river systems the migration is long, and fish concentrate below any structure that interrupts it — which is both an opportunity and, where the structure is a dam, a population-level problem.

THROUGH SUMMER THEY DISPERSE into deeper river channels and tailwater flats, and are harder to locate because they are spread rather than stacked.

AUTUMN AND WINTER ARE THE CLASSIC SAUGER SEASON. Fish concentrate in tailwaters and in deep wintering holes, and they feed actively in cold water. A tailwater in November or February with a jig worked slowly along the bottom is the archetypal sauger fishery, and it is happening while most river anglers have put their gear away.

LOW LIGHT IS THE OTHER HALF OF THE TIMING. Sauger feed hardest at dawn, dusk and after dark, and in coloured water at any hour. A bright still day on clear water is the worst combination available; a grey day on a coloured river is the best.

SO THE PRACTICAL RULE IS THAT SAUGER FISHING HAPPENS WHERE AND WHEN WALLEYE FISHING DOES NOT — coloured rather than clear, moving rather than still, cold rather than warm, and dark rather than bright. An angler who understands that difference has roughly twice as much fishable year as one who does not.

Sauger handling is a percid problem with a tailwater complication, and the second part is the one that gets overlooked.

THE TEETH AND SPINES ARE THE OBVIOUS PART. Prominent canines, a spiny first dorsal fin and sharp opercular edges mean a fish that is gripped carelessly will draw blood. A lip grip or a wet towel laid over the back controls the fish; long-nosed pliers keep fingers out of the mouth. Most injuries happen while removing a treble-hooked crankbait from a fish that is still moving, so controlling the fish before touching the hooks is the whole answer.

BAROTRAUMA IS THE COMPLICATION. Sauger are caught in deep tailwaters and deep river holes, and a fish brought up quickly from depth suffers swim-bladder expansion that it cannot correct. A fish that will not stay down when released, or whose stomach is visibly everted, has been injured by the ascent rather than by handling, and no amount of careful unhooking undoes it.

THE PRACTICAL RESPONSES ARE LIMITED AND WORTH KNOWING. Bringing fish up more slowly helps. Deciding in advance to keep fish from deep water — where the rules permit it — is more honest than releasing fish that will not survive. Descending devices, which return a fish to depth so it can recompress, are used in some fisheries and are worth having where deep-water release is routine.

AND THE SKIN AND SLIME MATTER AS THEY DO FOR ANY FISH. Wet hands, minimal air time, and support under the body rather than a vertical hold by the jaw for a heavy fish.

WHERE A FISH IS BEING KEPT, the catch-to-table records apply and the ordinary sequence — dispatch, then chill — is the one that decides whether it was worth keeping.