Hardhead catfish

Two hardhead catfish

Hardhead catfish are found mostly in the near-shore waters of the Western Atlantic Ocean, around the southeast coast of the United States, around the Florida Keys and the coast of the Gulf of Mexico.[4][5] Hardhead catfish are also found in brackish estuaries and river mouths where the bottom is sandy or muddy,[6] but only occasionally enter freshwater.[1] It tends to move from shallower to deeper waters in the winter months.[7] The species is generally common to abundant within its range.[1]

The hardhead catfish has four barbels under the chin, with two more at the corners of the mouth.[8] These barbels help the catfish find crabs, fish, and shrimp in the muddy bays where they live. The dorsal and pectoral fins each are supported by a sharp, slime-covered, barbed spine. The dorsal spine is normally erect when the fish is excited and a tennis shoe or even a leather-soled shoe offers little protection. The gafftopsail catfish looks similar to the hardhead catfish, but its dorsal and pectoral spines have a distinctive fleshy extension (like the fore-and-aft topsail of a ship).

A. felis consumes a wide range of food. It is an opportunistic consumer that uses mud and sand flats as hunting grounds.[8] It is also mainly a secondary consumer, ingesting primarily detritus, meio-, and macrobenthic fauna, and fish. Its diet primarily consists of algae, seagrasses, cnidarians, sea cucumbers, gastropods, polychaetes, shrimp, and crabs. It can occasionally be a tertiary consumer.[8]

Its diet depends on its size and location. Younger hardhead catfish tend to eat small crustaceans, like amphipods, shrimp, blue crabs, mollusks, and annelids.[9] Juveniles that are still under the protection of the male mouthbrooder feed predominately on planktonic crustaceans close by to the mouth of the parent.[8] The adults primarily consume larger fish.[9]

Significant evidence suggests correlation between the fish's activity patterns and seasonal changes. Under controlled conditions of photoperiod, temperature, and water quality, hardhead catfish display nonrandom oscillations in angular orientation of locomotive activity. There appears to be annual, bimodal cycles for all three of these variables. The cycles match with the seasonal inshore-offshore migrations of hardhead catfish. Photoperiod appears to be the exogenous cue that triggers the cyclic changes in behavior. The presence of this seasonal behavior indicates that a circadian neural mechanism may exist in hardhead catfish.[10]

The hardhead catfish has a reproductive season from around May to September.[14] Males and females reach sexual maturity before age 2.[8][14] Females at maturity are around 12.6–26.5 cm (5.0–10.4 in), and males typically are slightly larger, around 25 cm (9.8 in). At maturity, females develop flap-like fatty tissue by their pelvic fins, which results in them having larger pelvic fins than males. These enhanced pelvic fins may be the site of fertilization and play a part in moving the fertilized eggs to the male mouthbrooder for incubation. Another possibility is that males pick up eggs from depressions in the sand, as eggs tend to be demersal.[8] They also die after 4 years.

Hardhead catfish are voracious feeders and will bite on almost any natural bait. Hardhead catfish are also known to steal bait. Shrimp is a particularly effective bait to use. When fishing for this species in fresh water, assorted meats tend to work best as bait. For example: bacon, chicken, cuts of steak, and smaller fish. Hardhead catfish are generally regarded as an undesirable catch by most anglers, largely due to the risk associated with handling the venomous fish, as well as its 'fishy' taste as opposed to desirable game fish. Hardhead catfish are edible, but like all catfish, require some effort to clean. It is one of the 30 most recreationally harvested species in the five-county area (Volusia, Brevard, Indian River, St. Lucie, Martin) encompassing the Indian River Lagoon in central Florida.[8] From 1997 to 2001, 361,022 hardhead catfish were harvested within 200 miles of the shore in the IRL region.

Hardheads are also harvested for industrial purposes in commercial bottom-trawling operations. Annual harvests vary greatly, but from 1987 to 2001, 1.04 million pounds of marine catfishes (including both the hardhead catfish and the gafftopsail catfish) were harvested in the IRL region. The harvest was valued at $777,497.[8]

Hardhead catfish weigh around 1 lb (0.45 kg) and measure 10 to 12 in (25–30 cm) long.

As hardhead catfish grow longer, they increase in weight. The relationship between length and weight is not linear. The relationship between total length (L, in inches) and total weight (W, in pounds) for nearly all species of fish can be expressed by an equation of the form:

${\displaystyle W=cL^{b}\!\,}$

Invariably, b is close to 3.0 for all species, and c is a constant that varies among species. The relationship described in this section suggests that a 20 in (51 cm) hardhead catfish will weigh about 3 lb (1.4 kg), while a 25 in (64 cm) hardhead catfish will likely weigh at least 6 lb (2.7 kg).

• Smithsonian Marine Station at Fort Pierce