Redfish are primarily saltwater fish, commonly found in coastal marine environments across the Atlantic and Gulf of Mexico. These popular game fish are well-adapted to life in varied ocean conditions.
Identifying the Redfish
The fish commonly known as redfish is scientifically identified as Sciaenops ocellatus, also widely recognized as red drum. They are known by several other names including channel bass, puppy drum (for smaller individuals), and spot-tail bass. This species is distinct from other fish also sometimes called “redfish,” such as the deep-sea Acadian redfish (Sebastes fasciatus).
Red drum possess a distinctive appearance, typically showcasing a copper-bronze color on their back that gradually fades to a lighter, often white, belly. A prominent identifying feature is the presence of one or more dark, ocellated (eye-like) spots located near the base of their tail. While a single spot is common, multiple spots are not unusual, and very rarely, a redfish may have no spots at all.
These fish are characterized by large scales and powerful pharyngeal teeth, which they use to crush prey like oysters and other shellfish. Adult red drum can reach impressive sizes, with the largest recorded specimen weighing over 94 pounds and measuring more than 50 inches in length. Three-year-old red drum typically weigh between 6 to 8 pounds.
Their Preferred Habitat
Redfish are widely distributed along the Atlantic coast, from Massachusetts to Florida, and throughout the Gulf of Mexico to northern Mexico. They predominantly inhabit shallow coastal waters, thriving in estuaries, bays, and lagoons. These areas, where freshwater mixes with saltwater, support their life cycle.
Juvenile redfish primarily use these inshore, often brackish, environments as nursery grounds. These sheltered habitats offer abundant food sources like crustaceans and baitfish, and protection from predators. As they mature, redfish may transition to more saline waters, with larger individuals, called “bull reds,” moving to deeper coastal areas or offshore. They remain closely associated with structures like seagrass beds, oyster reefs, and mangroves, which provide foraging opportunities and cover.
Redfish and Salinity Adaptation
Redfish are known for their physiological adaptations that enable them to tolerate a broad range of salinities, from nearly fresh water to fully marine environments. While fundamentally adapted to saltwater, their ability to venture into lower-salinity areas is a significant aspect of their biology. This adaptability allows them to thrive in estuaries, which are dynamic mixing zones of fresh and saltwater.
Their bodies manage salt and water balance through a process called osmoregulation. In saltwater, redfish actively excrete excess salt through their gills and kidneys to maintain a stable internal environment. When in freshwater, their osmoregulatory mechanisms adjust to retain salts, which are naturally less abundant in the surrounding water.
Research indicates that the presence of specific minerals, such as calcium and magnesium, in freshwater is important for redfish to sustain proper osmoregulation in the absence of high salt concentrations. This explains why redfish can survive in certain “hard water” freshwater lakes, though they cannot reproduce there. Their eggs require high salinity to float and disperse.