Channel catfish

Channel catfish are strongly temperature-driven and their season is longer than most warm-water species' because they tolerate a wider band.

FEEDING RISES WITH TEMPERATURE through spring, peaks through summer, and continues well into autumn. Channel catfish remain catchable in cooler water than flathead catfish do, so the practical season is broader.

SPRING IS PRE-SPAWN FEEDING, with fish moving shallower and feeding heavily as water warms.

EARLY SUMMER IS SPAWNING, when males occupy and guard cavities and the fishery changes character for a few weeks.

MIDSUMMER AND AUTUMN IS THE MAIN FEEDING PERIOD, with fish active day and night, though the nocturnal habit is more pronounced in clear water and in heavily pressured fisheries.

WINTER SLOWS THEM SUBSTANTIALLY. Fish move to deeper holes and channels, group tightly, and feed little — but they do feed, and winter channel catfish fishing is a genuine if slow pursuit rather than an impossibility.

FLOW EVENTS ARE THE SHORT-TERM DRIVER IN RIVERS. A rise brings fish onto flats and into current seams to intercept displaced food, and falling water concentrates them back into holes. That response to flow is more immediate and more useful than any seasonal generalisation.

AND SCENT-BASED FEEDING MEANS TURBIDITY AND WARMTH WORK TOGETHER: warm, coloured, rising water is close to ideal, which is why the species is associated with conditions other fish find difficult.

The dorsal and both pectoral spines lock. That is the fact everything else follows from: a catfish that has raised its spines can hold them rigid, so a hand closing around the fish drives them in rather than folding them down.

The puncture is not the main problem. Catfish spines carry a venom gland at the base in many ictalurids, and the wound is deep, narrow and difficult to clean — a combination that produces infection rates far above what a similar cut would. Serious hand infections from catfish spines are common enough to be a recognised presentation in emergency medicine.

The grip that avoids it comes from behind: the hand slides forward from the tail with the palm under the belly, so the pectoral spines sit between the fingers rather than in them, and the dorsal is behind the thumb web. It feels wrong the first time and it is the only grip that works on a fish that is moving.

SMALL FISH INJURE MORE PEOPLE THAN LARGE ONES. A twenty-pound catfish is handled with two hands and full attention; a one-pound one is grabbed. The spines on the small fish are proportionally sharper and the handling is proportionally more casual, and that is where the punctures happen.

Channel catfish reproduction is a cavity-nesting strategy, and the requirement for an enclosed space is the constraint that governs where they recruit.

THE NEST IS A DARK ENCLOSED CAVITY RATHER THAN AN OPEN DEPRESSION. Channel catfish spawn in undercut banks, hollow logs, root masses, rock crevices, holes in bank structure and — very readily — in artificial cavities such as drainage pipes, drums and purpose-made spawning containers. The male selects and cleans the site, and the pair spawns inside it.

THE MALE THEN GUARDS AND TENDS THE EGG MASS. The eggs are laid as an adhesive gelatinous mass, and the male remains with them, fanning to keep them oxygenated and defending the cavity aggressively, continuing to guard the fry for a period after hatching. That is a substantial parental investment and it produces high survival per spawning.

WHICH MAKES CAVITY AVAILABILITY THE LIMITING FACTOR IN MANY WATERS. A river with excellent adult habitat and hardened, engineered, cavity-free banks recruits poorly, and the readiness with which the species adopts artificial cavities is why hatchery and pond production of channel catfish is so straightforward — supplying the missing habitat is easy.

TEMPERATURE TRIGGERS IT and spawning occurs in the warmer part of the year once water reaches the appropriate range, later in the north and earlier in the south.

TURBIDITY AND DARKNESS ARE NOT OBSTACLES, which follows from the record's sensory profile: this is a fish that locates everything by chemistry and touch, so a dark cavity in coloured water is a functional nursery rather than a compromise.

THE SPECIES IS WIDELY INTRODUCED, and the combination of tolerant adults, guarded nests and adaptability to artificial cavities is a substantial part of why it establishes so successfully outside its native range — with the consequences for native fauna that follow.

AND WHAT MAY BE DONE WITH A CAPTURED FISH, particularly outside the native range, differs between jurisdictions and is a matter for the competent authority.