Freshwater Fish - Species

Threadfin shad (Dorosoma petenense)

Description: (Anatomy of a Fish)

The threadfin shad has bluish gray on its upper side that fades into a silver side and belly.  There is a prominent purple to black spot on the upper side of the body just beyond the operculum or gill flap.  The caudal fin tends to be yellow.  A distinguishingly long dorsal fin ray occurs at the back of the dorsal fin. 

Range:  Statewide in large rivers and reservoirs

Average Length:  2-3 inches

Average Size:  1 ounce

Life Expectancy: Approximately 4 years

Preferred Habitat

The threadfin shad inhabits larger rivers and reservoirs primarily, but it is also found in brackish water. 

Food Habits

• Microscopic plants and animals by filter feeding with their gill rakers which function like a strainer catching food. 

Spawning

• Threadfin shad spawn from April to July in shallow shoreline areas, between dawn to sunrise over submerged plants or other objects.  The eggs sink and stick to various substrates until they hatch. 

Miscellaneous

The threadfin shad is considered by most fishery managers to be the single most important prey fish in South Carolina’s reservoirs.  Although the threadfin shad occurs in all but the coldest of the state’s waters, they are most productive in large impoundments.  In these impoundments, the shad rarely lives past one year, and during that time it grows no more than three or four inches in length.  This makes it an ideal sized food item for all advanced predators. 

Commonly Mistaken Species

One species of fish that is commonly mistaken for this species:

Literature Cited