It's Only Natural: Tropical fish make involuntary visits to our waters

One-Way Ticket




Each summer, many fish species visit the waters along the South Shore and Long Island Sound. Many of these fish are either here temporarily (migratory) or inhabit these waters year-round. They are here to feed on the abundance of food that thrives in our nutrient-rich marine environment. These fish will linger as they see necessary, feeding and accumulating the energy needed in preparation to migrate back to their wintering grounds, or venture offshore to hunker down for the winter.

Another unique group of fish is here as well during the summer, and the fish are seldom seen because they hide and are not here on their own willpower. They are tropical fish, but unlike the other fish groups, they will not be able to venture back in the winter to their tropical marine habitats.

These tropical fish arrive via the Gulf Stream. The Gulf Stream is a powerful, warm, and swift Atlantic Ocean current originating in the Gulf of Mexico, exiting through the Strait of Florida and flowing in a northerly direction along the southeastern coast of the United States and eventually passing Long Island 150 to 200 miles to our south.

This flow of water is part of the greater North Atlantic Gyre, which is one of the five major oceanic gyres found throughout the world. This gyre includes systems of circular ocean currents that stretch across the North Atlantic from near the equator, almost to Iceland, and from the east coast of North America to the west coasts of Europe and Africa. As the Gulf Stream current flows, it influences the climate on Long Island and also brings us an array of tropical visitors.

Every year in the Gulf of Mexico many types of tropical fish spawn, releasing free-floating eggs and developing larvae into the water column. As the Gulf Stream whips past these spawning grounds, it draws in anything in its path, especially young, developing fish that eventually find themselves drifting north and away from their home range. As these fish drift unwillingly along the east coast, they are pushed-out of the Gulf Stream current by large swirls of water known as eddies. These fish are then in a “race for time” to find a sanctuary and protection from predatory fish or birds. They dash and swim into our bays, harbors, and inshore waters, where they will stay and develop throughout the summer months.

As we enter the summer season here on the South Fork, there is no better opportunity to grab your snorkel gear and flippers and head down to the bay and to try to view these wonderful creatures, such as the lookdown, trigger, banded rudder, Jack Crevalle, spot-fin butterfly, glass-eye snapper, or even a bigeye. I have seen all these fish mentioned many times here on the East End in eelgrass habitats and around bridge and dock pilings.

When the local waters become cooler, these fish are triggered through their sensory systems to head back to a warmer environment and away from our inshore waters in search of the warm current that brought them here. As these fish swim offshore in search of this climate, they are preyed upon by migratory fish such as striped bass and blue fish. Those that make it back into the Gulf Stream will be heading in a northerly direction bringing them toward the frigid waters off Nova Scotia and Europe, where they will either perish due to the cold or be eaten by other predatory marine creatures.

Before these fish depart on this one-way journey, jump in the water this summer and search for these colorful and temporary visitors here on the East End. “Staycations” are all the rage these days, so living in a beach town is a definite bonus, especially when the beauty of the Caribbean is practically in our own backyard.

Frank Quevedo is the executive director of the South Fork Natural History Museum.