Herrings and shads, as a group, are silvery, flat-sided fish, easily recognized by the row of sharp-edged, spiny scales (or scutes) along the midline of the belly. These scutes are readily apparent when you rub your fingers forward along the fish’s belly.
The Alabama shad is similar to the skipjack herring, but the Alabama shad has the lower jaw equal to or projecting only slightly beyond the tip of the snout; its lower jaw has dark speckles along much of its length (not just near the tip); the teeth on the tongue are in a single row down the middle; and the gill rakers on the lower half of the first arch usually number more than 30 (the skipjack usually has fewer than 30). The last ray of the dorsal fin is not elongated into a long, slender filament. The principal rays of the dorsal fin usually number 16 or more.
Coloration is very similar to the skipjack herring: both have upperparts bluish or greenish with silvery reflections, shading to silvery white on the sides and belly. Both lack the dark spot behind the upper end of the gill opening, which is present on our other herrings.
Similar species: Four species in the herring family are recorded for Missouri:
- The skipjack herring (Alosa chrysochloris), as noted above, is the Missouri fish most similar to the Alabama shad. It is much more commonly encountered than the Alabama shad. The skipjack has the lower jaw projecting far beyond the tip of the snout; dark speckles only near the tip of the lower jaw; teeth on the tongue in 2–4 rows; and gill rakers on the lower half of the first arch usually fewer than 30.
- Both the threadfin shad and gizzard shad may be separated from both the Alabama shad and the skipjack herring by their last dorsal fin ray being elongated into a long, slender filament and by a dark spot present behind the upper end of the gill opening. Also, the principal rays of the dorsal fin usually are 14 or fewer.
Members of the herring family might be mistaken for the mooneye and goldeye (which are in a different family), but herrings have the following key characters: The dorsal fin is far forward of the anal fin. The head is without scales, but the body is covered with thin, smooth-edged (cycloid) scales that are easily dislodged. The lateral line is absent. A small, triangular projection (an axillary process) is present just above the base of the pelvic fin, and the eyes are partly covered by transparent membranes (adipose eyelids).
Habitat and Conservation
In the early 20th century, the Alabama shad was reported in the Mississippi River system from the Ohio River at Louisville, from the Mississippi River near Keokuk, and from Oklahoma. At that time it was common enough to supported a limited commercial fishery.
Since then, it underwent a marked decline, and at this point, Missouri may have the last spawning populations in the Mississippi River system. It has occasionally been reported from our state from the lower Mississippi, Missouri, Meramec, Gasconade, and Osage rivers. More than 10 times as many juveniles as adults have generally been collected. The size, condition, and timing of the collections indicate this species is probably spawning here.
In the Osage River, young were captured in swift water about rock wing dikes. In the Gasconade River, they were collected over rocky shoals having noticeable current.
A Species of Conservation Concern in Missouri. Listed as imperiled and vulnerable to extirpation from the state. Also listed globally as vulnerable to extinction. It is under consideration for listing under the U.S. Endangered Species Act.
The decline in Alabama shad seems to be connected to the construction of many locks and dams on rivers, which prevent them from being able to migrate upstream to their ancestral spawning territories.
The flesh of Alabama shad is reported to be comparable in flavor to that of the Atlantic shad, a highly regarded food fish that enters streams along the Atlantic Coast. The Alabama shad does not support a commercial fishery, however, not even in the Apalachicola River of Florida where large spawning runs occur. However, some are taken there by sport fishers while fishing for other species.
Human-built dams can have dramatic impacts on fish populations, as they seem to have done with this species: reducing its overall range and hampering its migrations and ability to reproduce.
The herring family is primarily marine. Many herring and shad are anadromous, spending most of their adult life in saltwater but ascending freshwater streams to spawn. Of Missouri’s species, this is the only one that is anadromous. Our other three species can complete their entire life cycle in freshwater.
Alabama shad consume, and therefore serve to limit, the populations of aquatic insects and small fishes. When they are young, shad provide food for a variety of larger fish, plus fish-eating birds, reptiles, and mammals. Larger shad, however, have fewer predators.
A relative, the American shad (A. sapidissama) is native along the Atlantic Coast and has been a popular food fish (both for its flesh and its roe) since the early years of our nation. Prior to spawning, large schools of them swim up coastal rivers in “runs.” That species was long ago introduced to the West Coast and now also occurs from San Francisco Bay and northward.