Red drum

Red drum are among the more forgiving fish to handle, and the important intelligence is about which fish you are holding rather than about how to hold it.

THE FISH ITSELF. No cutting teeth — a hard, bony mouth with crushing pharyngeal plates for shellfish. Stiff dorsal spines and hard gill covers that will graze a hand. Lipping is safe with body support; a hand across the back finds the dorsal.

THEY ARE ROBUST and survive release well in the temperate and subtropical water they are usually caught in, which is why the fishery supports the pressure it does.

BUT THE LARGE ONES ARE THE POPULATION. Red drum spend their early years inshore and move offshore to join the spawning stock as they mature, so the very large fish — the bull reds — are the breeding adults. Slot limits exist to protect exactly those fish, and this is the clearest example in American saltwater fishing of a rule whose logic is worth understanding rather than merely obeying: keeping the mid-sized fish and releasing the big ones is the opposite of the trophy instinct and it is what keeps the fishery working.

SO A LARGE RED DRUM IS RELEASED, and it should be released properly: horizontal support with two hands, no hanging by the jaw, minimal air time, and revived in the water until it swims off strongly. A forty-inch fish held vertically for a photograph is being damaged.

AND THE WADING HAZARD IS THE ANGLER'S. Red drum are fished on shallow flats holding stingrays. Shuffle rather than step.

Red drum reproduction is organised around getting larvae into the right water, and the species announces the whole process audibly.

THE SOUND IS REAL AND IT IS THE FAMILY'S NAME. Males produce a drumming or croaking noise by contracting specialised muscles against the swim bladder, which acts as a resonating chamber. During the spawning period this is loud enough to be heard by people standing nearby or on a boat above them, and a spawning aggregation of red drum is genuinely audible. It is a courtship signal, and it is one of the few pieces of fish reproductive behaviour a person can perceive without instruments.

THE TIMING IS TIDAL ENGINEERING. Spawning occurs in nearshore water and around inlets, timed so that the buoyant eggs and the larvae that hatch from them are carried by tidal flow into shallow estuarine nursery habitat — marsh edge, seagrass, shallow creek. As with snook, the site is chosen for where the water goes rather than for the comfort of the adults, and the nursery habitat is the part that determines whether any of it works.

AND THE LIFE HISTORY PRODUCES AN UNUSUAL FISHERY STRUCTURE. Red drum spend their early years in estuaries and then, as they mature, move to nearshore and offshore waters — so the population is spatially sorted by age. The small and medium fish are inside; the large breeding adults, the bull reds, are outside. An inshore angler and an offshore angler are fishing different parts of the same population.

THAT IS THE REASONING BEHIND SLOT LIMITS, which are a common instrument for this species. A slot protects the small fish that have not yet spawned AND the large fish that do most of the spawning, permitting harvest only from the middle. It is a management design that follows directly from a population whose reproductive value is concentrated at one end of the size range, and it is worth understanding as a piece of reasoning rather than as an arbitrary rule.

FishingHQ does not state what any slot limit, season or bag limit currently is anywhere. Those are local, they change, and the biology above is the durable part.

Red drum habitat is best understood as a single system that the fish moves through as it grows, which is why the inshore and offshore fisheries for the species look like they are for different animals.

THE JUVENILE HABITAT IS THE SHALLOW ESTUARY. Larvae are carried on tidal flow into estuarine nurseries and settle into the shallowest, most sheltered water available — marsh edge, seagrass, oyster ground, shallow creek and mud flat. Those places offer two things a small fish requires: enormous invertebrate productivity, and water so shallow that most predators cannot follow. Red drum spend their early years there and are the fish an inshore angler catches.

AS THEY GROW THEY MOVE OUT. Larger fish use deeper estuarine channels, passes and nearshore water, and mature adults — the bull reds — occupy nearshore and offshore coastal water, returning toward inlets to spawn. So the population is spatially sorted by age along a gradient from marsh to ocean, and an inshore angler and an offshore angler are working different segments of the same stock.

WITHIN THE ESTUARY THEY FEED HEAD-DOWN ON THE BOTTOM. Red drum have a sub-terminal mouth and take crustaceans and molluscs from sediment and shell, which is why they tail in shallow water — the fish is nose-down on the bottom and its tail comes out of the water — and why the classic sight fishery works at all. That feeding mode ties them to soft and shelled bottom rather than to open water.

SALINITY TOLERANCE IS UNUSUALLY BROAD, which is what allows all of this. Red drum handle nearly fresh water to full seawater, so they use the whole estuarine gradient rather than a band within it, and they move up and down it with rainfall, tide and season.

AND THE OYSTER REEF AND MARSH ARE THE LOAD-BEARING PARTS. Both provide the structure, the invertebrates and the shelter the juvenile stage depends on, and both are lost to dredging, shoreline hardening, subsidence and water-quality decline. A coast can hold plenty of adult red drum offshore and be steadily failing to produce them, and the failure is happening in water too shallow for anybody to be fishing.

Red drum have one of the clearest split seasonal patterns of any inshore fish, and the split is by size and life stage rather than by month.

THE SMALLER FISH ARE ESTUARINE RESIDENTS AND THEIR YEAR IS A TEMPERATURE CYCLE. Juvenile and sub-adult red drum live in estuaries, marshes, creeks and shallow bays for their first several years. Through the warm months they are spread across flats, marsh edge and shallow shorelines feeding on crustaceans and small fish; as water cools they concentrate in deeper holes, channels and creeks where temperature is stable, and in cold snaps they can be found stacked in remarkable densities in a small amount of deep water. That concentration is a survival response, and it makes them both findable and fragile at the same time.

THE LARGE FISH ARE A DIFFERENT ANIMAL SEASONALLY. Mature red drum leave the estuaries and live in coastal and nearshore waters, and in late summer and autumn they aggregate to spawn — near inlets, passes and the mouths of estuaries, in large schools of big fish. That autumn aggregation is the origin of the entire big-fish fishery, and it is a spawning event rather than a feeding one.

WHICH MATTERS FOR HOW THOSE FISH ARE TREATED. A spawning aggregation of old, highly fecund females is the most valuable and most vulnerable concentration the population produces. Many jurisdictions manage that specifically, often with slot limits that protect large fish. What the rules are on any coast is a matter for the competent authority, and they are not inferable from the biology.

JUVENILES RECRUIT INTO THE MARSH IN AUTUMN AND WINTER. Larvae spawned near the inlets are carried into the estuary and settle into shallow marsh and seagrass, so the year class produced by one autumn's spawning appears in the shallows a few months later. Marsh condition in that window drives recruitment strongly.

AND THE SPECIES TOLERATES A GREAT DEAL, which flattens the seasonal signal in the warm parts of the range. Red drum handle a wide temperature and salinity range, so in the southern part of the range they are catchable year-round and the season is about where they are rather than whether they are there. Further north, cold winters produce genuine seasonal absence and occasional cold-kill events.