Black drum

Black drum occupy shallow, turbid, soft-bottomed coastal water, and their habitat use follows directly from what they eat.

THEY ARE SHELLFISH SPECIALISTS with powerful pharyngeal teeth capable of crushing oysters, clams and crabs. Habitat is therefore wherever those occur in quantity: oyster reef, shell bottom, mud and sand flats, and the margins of bays and estuaries.

TURBIDITY IS NOT A PROBLEM AND IS ARGUABLY AN ADVANTAGE. Black drum hunt by scent, touch and the lateral line rather than by sight, using chin barbels to locate buried prey, so the muddy water of a bay or a river mouth is prime habitat rather than a compromise.

SALINITY TOLERANCE IS BROAD. The species moves freely between full-strength coastal water and distinctly brackish estuary, and juveniles in particular use low-salinity backwaters and marsh as nursery ground.

DEPTH IS SHALLOW FOR MOST OF THE YEAR — bays, channels, passes and surf — with larger fish moving to deeper channels and nearshore Gulf and Atlantic water seasonally.

JUVENILE AND ADULT HABITAT DIFFER SHARPLY. Young fish are marsh and estuary residents; very large old fish are found in deeper channels and around passes and jetties, and the two rarely share ground.

AND STRUCTURE MATTERS LESS THAN BOTTOM TYPE. A black drum is looking for something buried, so the presence of a shell or clam bed predicts them better than a piece of hard structure does.

Black drum reproduction combines a distinctive sound-based courtship with extreme longevity, and the combination has real management consequences.

THE NAME IS THE BEHAVIOUR. Males produce a low drumming sound by vibrating muscles against the swim bladder, and the sound is central to spawning aggregation and courtship. It is loud enough to be heard from boats and through hulls, and acoustic surveys of spawning aggregations use it directly.

SPAWNING HAPPENS IN AND AROUND PASSES AND BAY MOUTHS, where fish gather in the cooler part of the year and release eggs into water that will carry the larvae into the estuary. Eggs and larvae are pelagic and recruitment depends on that transport working.

THE TRIGGER IS TEMPERATURE AND PHOTOPERIOD, with spawning concentrated in late winter and spring in the Gulf and south Atlantic, earlier than most of the species sharing that water.

MATURITY COMES EARLY BUT LIFE IS VERY LONG. Black drum are among the longest-lived inshore fishes, with documented ages beyond half a century. A large old drum represents decades of accumulated reproduction, and the biggest fish are disproportionately productive.

WHICH IS WHY THE HANDLING OF LARGE FISH MATTERS MORE THAN THE NUMBERS SUGGEST. Very large black drum are poor eating and highly valuable reproductively, and the practice of releasing them is a stock decision rather than a preference.

THERE IS NO NEST AND NO PARENTAL CARE — the investment is entirely in volume and in the timing that puts larvae where the currents will help them.

Black drum have an unusual seasonal pattern for a warm-water inshore fish: their most concentrated period is the cool one.

THE SPAWNING RUN IS LATE WINTER AND SPRING in the Gulf and south Atlantic, when large fish gather around passes, bay mouths and jetties. That is the period when the biggest fish are most concentrated and most accessible, and it is the aggregation that carries the population's reproduction.

SUMMER DISPERSES THEM INTO THE BAYS AND MARSH, where smaller and medium fish feed over shell and mud on crabs and shellfish, and the fishery becomes a shallow-water one for eating-sized fish.

WINTER PUSHES FISH INTO DEEPER CHANNELS AND HOLES as shallow water cools, and cold snaps in shallow bays can produce local mortality events — a genuine seasonal risk for the species at the northern edge of its range.

THE PRACTICAL EATING SEASONALITY IS SIZE RATHER THAN MONTH. Smaller drum are good eating year-round; very large ones are coarse and frequently carry parasites, and the seasonal concentration of large fish therefore coincides with the fish least worth keeping — which is a fortunate alignment rather than a designed one.

AND THE DRUMMING IS SEASONAL TOO, audible around aggregations in the spawning period and largely absent outside it, which makes the sound itself a seasonal indicator.

Nothing here indicates what any current season, size or bag rule permits.

Black drum carry no teeth in the jaws worth worrying about and a set of pharyngeal crushing plates deep in the throat that will damage a finger exploring where it should not be. The plates exist to break shellfish and they are entirely capable of it.

The gill covers are sharp, and the fish is heavy. A large black drum is supported horizontally with two hands or handled in the water; lifting one by the jaw puts the whole mass on a joint not built for it.

The fact that changes the handling decision is longevity. Black drum are among the longest-lived inshore fish in the western Atlantic, and a large one may have been alive for decades. Returning it properly is therefore worth disproportionately more than returning a small one, and the same is true of the effort spent reviving it.

The ground carries its own hazard, as it does for most of this fishery: much of it is conducted wading shallow estuarine flats and bars that also hold stingrays buried in soft bottom. Shuffling rather than stepping is the whole of the precaution and it works.