Spotted seatrout have a streamlined body that is dark silvery gray on the back, shading to white below. The upper parts of the fish have an iridescent sheen and have a few to many black spots. The dorsal and tail fin are always spotted. Occasionally, a spotted seatrout is captured with spots only on the fins and not the body. Their mouth is often, but not always, splashed with yellow pigment on the edges and interiors, and 1 or 2 large sharp canine teeth are located at the front of the upper jaw.

That speckled trout move within an estuary on a yearly basis is well known. Typically, they spend their summers in the high-salinity areas in the lower part of an estuary and their winters in the lower salinity waters of the upper estuary. But how far speckled trout move from estuary to estuary or bay to bay is not well known by most fishermen.

Speckled trout tend to live in or near the same bay system all their lives. In 1979, Louisiana researchers tagged over 2,600 specks. Of the 30 returns that they got, 20 came from the tag and release site. Similar Louisiana research published in 1980 and 1982 showed that 90% of tag returns came from within one mile of where the trout were tagged, although another researcher in 1982 noted that two speckled trout tagged in Calcasieu Lake were recovered 96 miles to the east in Atchafalaya Bay.

Texas research results were similar. Results of 20,912 trout tagged in bays between 1975 and 1993 showed 84% of the returns came from the same bay as release. The longest distance traveled by any tagged speckled trout before recovery was 131 miles. Of 588 trout tagged in the Texas Gulf surf, 12 were recovered in the Gulf and 2 in Texas bays.

Other states show similar research results. In Mississippi, 7,423 specks were tagged, with 221 recovered, and 90% of these were recaptured within 5 miles of their release location. In Alabama, 53% of tagged speckled trout showed no movement and the longest distance traveled was under 20 miles. Multiple studies in Florida showed that speckled trout seldom move over 30 miles and that most fish never left the estuary, although one fish tagged in the Apalachicola, Florida area was recovered 315 miles away near Grand Isle, Louisiana.

Spotted seatrout do move seasonally within a bay system, however. During the pre-spawning period of February to early April, speckled trout are scattered throughout the system. By spawning season, May to September, almost all the fish large enough to spawn are concentrated in the higher salinity waters of the lower bays. In October, with the onset of cool fronts, spotted seatrout retreat inland into lower salinity estuaries, where they typically remain well into January or February.

During spawning season, males form drumming aggregations which can number in the hundreds or even thousands of fish. Within these aggregations, each male vibrates his air bladder, producing a croaking sound. When combined with the many other males' sounds, the result sounds like drumming or roaring. The sound attracts females ready to spawn. Both drumming aggregations and spawning take place in areas 6-165 deep with good tidal flow, such as passes and channels. Spawning begins at sunset and is usually over by midnight.

Speckled trout spawning activity depends on environmental factors such as currents, salinity and temperature. Most spawning activity seems to take place in salinities of 17-35 parts per thousand (ppt). Full strength seawater is 35 ppt. The two most important factors that determine when speckled trout spawn are water temperature and day length. Egg development begins to take place as days become longer in spring. Water temperatures of 68ºF seem to trigger spawning, which continues as water temperature increases. Peak spawning takes place between 77ºF and 86ºF. The cycle of the moon also seems to affect spawning, with spawning peaks occurring on or near the full moons of the spring and summer months. Females may spawn every 7 to 14 days during the April to September spawning period.

Young spotted seatrout grow rapidly, reaching 8 inches by their first birthday and over 12 inches by age 2. Spotted seatrout can live to over 12 years of age. Male trout grow slower and don't live as long as females. Males don't reach 14 inches long until 3 or 4 years old. Few males live over 5, so virtually all spotted seatrout 5 pounds and larger are females.

Spotted seatrout are voracious predators, especially in the summer when high spawning activity creates tremendous metabolic demands. Fish under 12-14 inches eat a variety of foods, but more shrimp and other crustaceans than anything else. As they grow, they shift their food preference to fish, first to smaller fish such as silversides and anchovies, then later to larger prey fishes such as mullets, croakers and menhaden.