"Estuaries such as Long Island Sound are among the most valuable ecosystems in the world. The Sound supports diverse marine life, including most of the fish and shellfish we value as food ..."

– Connecticut Sea Grant

Conservation & Research

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Long Island Sound Fun Fact

Long Island Sound is 113 miles long, 21 miles wide (at its widest) and holds about 18 trillion gallons of water. Its average depth is 63 feet – which is just a little deeper than the height of our IMAX screen! Can you fathom that?!

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Common Name: Moon jelly

Latin Name: Aurelia aurita

Size/weight: Up to 16 inches in diameter

Range:  Arctic to Florida or Mexican; in the Pacific from Alaska to southern California

Habitat: Floats near surface in offshore waters.

Diet: Small plankton, fish eggs, occasionally other developing jellies.

Predators: Sea turtles, sunfish.

Description: Translucent; recognizable for the four horseshoe-shaped organs in their center and a single row of short, hair-like tentacles around the bell.  Since they’re not really fish, it is more proper now to call them “jellies,” instead of jellyfish.  Moon jellies are only mildly toxic to most people; the sting is likely to cause nothing more than a persistent, itchy rash. But some folks may have more severe reactions.

Conservation Note: An abundant, non-threatened species.

See them in the Jellyfish Encounter exhibit and touch them at the "Jiggle A Jelly" exhibit! »

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Common Name: Eastern oyster (sometimes called American or Virginia oyster)  

Latin Name:  Crassostrea virginica

Description:  A prolific bivalve mollusk with thick irregular grayish-white shells with concentric ridges. The left (or bottom) shell is cupped with a purple muscle scar inside. The right (or top) shell is smaller and flatter.

Size/weight:  Shells generally are 3 to 5 inches long

Range:  Eastern North America, from the Gulf of St. Lawrence to the Gulf of Mexico 

Habitat:  Estuarine or salty water, in intertidal and subtidal zones. They can grow in great beds or reefs, with new immature animals "setting" on old empty shells. Oyster reefs provide bottom habitat for other marine invertebrates and fish species.

Diet:  Oysters are filter-feeders. They open their shell & pump in water, which draws planktonic food in as well. (Oysters filter so much water that a large population of oysters can effectively help keep a body of water clean.)

Predators:  Sea stars, crabs, oyster drills and other snails, some fish, humans.

Note:  The Eastern oyster was designated as Connecticut's state shellfish in 1989.  

Norwalk and the Eastern oyster go way back. The city’s Oyster Shell Park, which extends up the pathway along the Norwalk River north of the Aquarium, was once the site of a native American oyster midden – a place where the local tribe piled up its empty oyster shells.

The waters of Long Island Sound just off of Norwalk are a perfect place for oysters, offering just the right temperatures, salinities, substrate and currents, plus a lack of severe storms. Oysters grow wild, but – even by the early 1700s – were being farmed as well. Oystering boomed through the 1800s, serving as a huge economic driver for Connecticut’s shoreline communities. And these just weren’t any oysters. The oystermen were farming a particular variety with a deliciously distinct taste they called Bluepoints.  They could barely keep up with the demand.

(In The Maritime Aquarium at our Toy Boat-Making workshop, check out a 1937 Works Progress Administration – or WPA – mural of an oyster-shucking operation.)

Oystering in the Sound hit hard times in the early half of the 20th century (mainly from pollution) and in the late 1990s (from parasites). But the industry is thriving again today, with two of Connecticut’s biggest companies based on either side of the Norwalk harbor.  Oyster connoisseurs still rank Bluepoints among the best in the world. The legendary Oyster Bar restaurant in Grand Central Station reportedly serves 1,000 Norwalk oysters a day – one-fourth of them Bluepoints.

See oyster shells in one of the salt-marsh gallery exhibits, and touch them at our Intertidal Touch Tank.

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Common Name: North American river otter

Latin Name: Lontra canadensis

Size/weight:  Adult size is about 2.5 – 5 feet long (with tail) and 10 – 30 pounds.

Range: Throughout North America (Alaska, Canada and the lower 48 United States).

Habitat:  River otters can be found in or near fresh water (lakes, streams, marshes, etc…) and in brackish waters.  They build their dens (or take over abandoned dens of other animals) in riverbanks or in a natural hollow near the water.

Diet:  North American river otters find most of their food in the water; amphibians, fish, turtles, crayfish, crabs and other invertebrates are favorites.  Birds, eggs, aquatic plants, and small land mammals are sometimes on a river otter’s menu.

Predators:  Bobcats, coyotes, birds of prey, dogs. Hunting.

Description:  With their long, streamlined bodies and thick, tapered tails North American River otters are well suited to a life around the water. (Although they run with a distinctive "humpbacked" gait, they can run even faster than they can swim.) Otter fur is thick and dark brown, lighter on the underside.  Long, sensitive whiskers help them find food under water. 

Conservation Note:  Once heavily hunted for their fur, North American river otter populations continue to rebound. In Connecticut, the population is large and stable enough to have a legal trapping season. Threats come from development and pollution, as otters prefer quiet areas with clean water.

See Lew & Levi in the Rivers to the Sound watershed gallery »

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Common Name: Atlantic salmon (East Coast)

Latin Name: Salmo salar

Size/weight: Up to 4.5 feet and 80 pounds

Range: Arctic Circle to Delaware River, also some landlocked populations.

Habitat: Coastal waters, as well as freshwater rivers and lakes.

Diet: Herring, capelin, sand eels and large plankton.

Predators: Seals, sharks, pollack, tuna, skates, halibut, cod, striped bass, bluefish; humans.

Description:  Long body, brownish above with silvery sides featuring black spots.  Lower jaw hooked up in breeding males, who may also feature red areas on their sides.  Spawns in fresh water, but spends most of its life at sea.

Conservation Note: Listed on the U.S. Endangered Species List due to overfishing, disease, interaction with hatchery populations, and dammed and polluted spawning rivers. Seafood Watch lists farmed Atlantic salmon as a seafood to Avoid, and says Alaskan wild salmon is the Best Choice.

See them in the Rivers to the Sound watershed gallery and in "Go Fish!" »

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Common Name: Lined seahorse

Latin Name: Hippocampus erectus

Size/weight:  Up to 5 inches

Range: Nova Scotia to Argentina; Bermuda and Gulf of Mexico

Habitat: Found in shallow waters among grasses

Diet:  Brine shrimp and other live zooplankton.

Predators: Crabs, skates and rays; humans.

Description: Body is upright with a head (shaped liked a horse head) perpendicular to body.  Dorsal fin is fan shaped.  Tail is prehensile and lacks a caudal fin.  Color varies from light brown to almost black and can change depending on the background.  It is the male of the species that gives birth.

Conservation Note:  Considered a vulnerable species due to pollution, habitat destruction and overfishing (with a high demand from the Asian market for use in traditional medicines, and as a desirable fish for home aquariums).

See them in the Salt Marsh gallery »