Sharks are present in the Long Island Sound, an estuary separating Connecticut and New York. This body of water, over 100 miles long, connects to the Atlantic Ocean through a narrow eastern passage known as The Race. While their existence is a verifiable fact, the public’s perception often overstates the frequency and danger involved.
Confirmed Shark Species in Long Island Sound
Four shark species are commonly considered residents or regular seasonal visitors to the Long Island Sound. The most frequently encountered are the two smaller species, the spiny dogfish and the smooth dogfish. Spiny dogfish are slender, reaching lengths of about four feet, and often travel in large schools near the bottom. The smooth dogfish, sometimes called a sand shark, grows up to five feet and thrives in the Sound’s brackish water by feeding on crustaceans and mollusks.
The Sound also hosts two larger species: the sand tiger shark and the sandbar shark. Sand tiger sharks are the largest species native to the area, growing up to ten feet long. Despite their formidable appearance, characterized by constantly visible, jagged teeth, they are known to be docile toward humans. Sandbar sharks, also known as brown sharks, can reach eight feet and are notable for their tall dorsal fin.
Transient pelagic species like the great white shark or bull shark may rarely enter the Sound, typically in the eastern portion near the ocean opening. A tagged, nearly ten-foot great white shark was detected in the western Sound off Greenwich, Connecticut, in 2019, confirming these larger animals occasionally venture inside. Their visits are isolated occurrences and do not represent a permanent presence.
Movement Patterns and Seasonal Presence
Shark presence in the Long Island Sound depends highly on seasonal migration driven by changing water temperatures and prey availability. Most sharks move into the New York and Connecticut coastal waters during the late spring and summer months. This migration is a response to warmer surface temperatures and the abundance of schooling baitfish, such as Atlantic menhaden, which enter the Sound to feed.
The Sound and nearby coastal areas serve as sheltered habitats for some species. Juvenile sand tiger sharks, for example, migrate north from birthing grounds in the Southeast. They spend summers in protected, food-rich coastal bays of Long Island, such as the Great South Bay, which acts as a known nursery ground. These young sharks remain in the area for several years to feed and grow before returning south in the fall.
Seasonal movement is influenced by environmental factors like sea temperature and the photoperiod, or length of daylight. As ocean temperatures continue to rise, some species, particularly the sandbar shark, may linger in northern waters for an extended period, shifting the timing of their traditional fall migration south. The deep, swift currents of The Race at the Sound’s eastern end act as the most likely entry and exit point for these migratory and transient species.
Assessing the Risk to Swimmers
The risk of a shark encounter in the Long Island Sound is low, as documented unprovoked attacks are rare throughout the region’s history. While coastal waters off Long Island’s ocean-facing beaches have seen a slight increase in minor bites recently, incidents within the Sound itself are less common. Historically, the few recorded incidents in the Sound involved superficial injuries or were attributed to mistaken identity by smaller, juvenile sharks.
Sharks that enter the Sound focus on their natural diet of fish, skates, and crustaceans, and they do not view humans as prey. Incidental bites are often attributed to the shark confusing a swimmer’s hands or feet with the small baitfish they pursue in shallow, murky waters. The presence of large schools of prey fish close to shore is a major factor that draws sharks into proximity with beachgoers.
Swimmers can minimize risk by following basic precautions. This includes avoiding swimming at dawn, dusk, and at night, which are the times when many shark species actively feed. It is also advisable to avoid areas where schools of bait fish are visible, often indicated by diving seabirds or splashing. Swimmers should also remain close to shore where lifeguards are on duty.