Sandbar sharks, scientifically known as Carcharhinus plumbeus, are a species of requiem shark commonly found in temperate and tropical coastal waters across the globe. These sharks often inhabit sandy or muddy bottoms in shallow areas, including bays, harbors, and estuaries. They are recognized as a medium-to-large coastal shark, and in the Western Atlantic, they are one of the most frequently encountered large shark species.
Adult Size and Appearance
Adult sandbar sharks typically measure around 6 feet (1.8 meters) in length. Females of the species generally attain larger sizes than males, with females growing to about 6.6 to 8.2 feet (2 to 2.5 meters), while males usually reach up to 5.9 feet (1.8 meters). The maximum recorded length for a sandbar shark is approximately 8 feet (2.4 to 2.5 meters).
These sharks generally weigh between 100 to 200 pounds (45 to 90 kilograms). The largest recorded sandbar shark weighed around 260 pounds (118 kilograms). Sandbar sharks possess a robust body, typically displaying a brownish-gray to bronze coloration on their upper side, which fades to a white or pale underside. A distinguishing feature is their tall, triangular first dorsal fin, along with large pectoral fins and a rounded snout that is shorter than the average shark’s snout. They also have an interdorsal ridge, a ridge of skin between their two dorsal fins.
From Birth to Full Growth
Sandbar shark pups are born live in shallow, nearshore nursery grounds, measuring 20 to 25 inches (50 to 65 centimeters) in length. They are born live in shallow, nearshore nursery grounds, which provide a protected environment for the young. These sharks exhibit a slow growth rate throughout their development.
Males generally reach sexual maturity between 11.6 and 13 years of age, while females mature later, typically between 14 and 16 years. Some studies indicate that full maturity might take up to 30 years. Factors influencing their size and growth include their age, sex, and the availability of food resources within their habitat.
Ecological Role and Conservation
Sandbar sharks are important predators within their coastal habitats. They function as apex or mesopredators, consuming a diverse diet of bony fish, smaller sharks, octopuses, squid, eels, skates, rays, shrimp, and crabs. This helps regulate marine food webs.
However, their life history traits, including a slow growth rate, late sexual maturity, and the production of relatively few offspring (typically 1 to 14 pups per litter, with an average of 8 to 9), make them particularly susceptible to fishing pressures. Consequently, sandbar shark populations in some areas, such as the U.S. Atlantic, have been classified as overfished. Globally, the species is listed as Endangered by the IUCN. To address these concerns, sandbar sharks are managed under regulations like the Magnuson-Stevens Fishery Conservation and Management Act in the U.S. These measures prohibit commercial and recreational harvest in U.S. Atlantic waters, with a limited research fishery permitted to gather data for stock assessments and conservation efforts.