Photos of the Long Island Sound

Status and Trends: LISS Environmental Indicators

Type of Indicators: Health/Condition Response/Performance Socio-Economic Historical/Background

Marine and Coastal Animals

Marine and coastal animal indicators include species of finfish, marine invertebrates, and coastal birds. The abundance of selected species is used to assess the overall health of populations and their habitats in the Sound. Measuring the value of commercial fisheries helps to evaluate the economic importance of the Sound.

Invertebrates (including shellfish)

Horseshoe Crab Abundance

This indicator shows the abundance of Horseshoe Crabs in Connecticut and New York. View Indicator

Lobster Abundance

Lobster has historically been an important fishery in Long Island Sound but populations have declined in recent years. This indicator is a fisheries-independent estimation of their abundance in the Sound. View Indicator

Lobster Landings

This indicator reports the number of lobsters taken from traps by commercial lobsterman in Long Island Sound. View Indicator

Approved Shellfish Acreage

This measure indicates whether water quality conditions in tidal rivers and coastal waters can support recreational and commercial shellfishing of oysters and clams. View Indicator

Hard Clam Harvest

This indicator reports the number of bushels of hard clams harvested commercially each year in Long Island Sound. View Indicator

Oyster Harvest

This indicator reports the number of oysters harvested commercially each year in Long Island Sound View Indicator


Spawning Runs in LIS tributaries

Index of Anadromous Fish Runs

These counts of river herring and shad in Long Island Sound tributaries indicate the quality of upstream habitat that has been opened up as a result of completed fishway projects. View Indicator

Herring Runs at Streams with Upstream Planned Fishway Projects

These counts indicate progress in expanding upstream habitat as fishway projects are completed. View Indicator

Atlantic Salmon Restoration in the CT River

This indicator is the abundance of Atlantic salmon counted at observation stations in the Connecticut River from 1967-2009. View Indicator

Fish Populations in Long Island Sound

Forage Fish – Open Water/CT Coastline

The forage indices measures the productivity of small fish in the Sound, which is the basis of the food supply for larger fish, including game fish. View Indicator

Finfish Biomass Index/Species Richness

Fish biomass indicates the productivity of the Long Island Sound fishery. Species richness measures the diversity of species supported within the Sound's various habitats. View Indicator

Game Fish

The abundance of game fish is a reflection of the productivity of Long Island Sound and the effectiveness of coast-wide fishery management plans that seek to stabilize populations while maximizing harvest opportunities. View Indicator

Water Temperature

Yearly seasonal temperatures from 1976-2011, measured in Niantic Bay by the Millstone Environmental Lab. View Indicator

Shad & Blueback Herring—Long Island Sound

Abundance of American shad and blueback herring, as reported in the Long Island Sound Trawl Survey. View Indicator

Coastal Birds

Least Terns

The Least Tern is the smallest of American Terns. They are migratory birds that breed along marine and estuarine shores of the United States. Their abundance indicates the quality of coastal habitat and quantity of forage fish available for food. View Indicator

Piping Plovers

Piping plovers are small shorebirds that nest on the beaches of Long Island Sound. The abundance of breeding pairs reflects availability of beach nesting habitat and management efforts to protect nesting pairs from human intrusion, storm tides and predators. View Indicator


Osprey are one of the largest birds of prey in North America, and found throughout the world. Their population was seriously affected by pesticides such as DDT in the 1950s and 1960s. Populations recovered due to the ban on DDT and management efforts to increase available habitat. Populations have recovered to the point where state conservationists have stopped tracking their numbers. View Indicator

Colonial Waterbirds

Colonial waterbirds nest primarily in groups on islands along the Atlantic coast and often feed on estuarine fish and invertebrates. The abundance of these birds indicates the ability of local salt marshes to provide a habitat for the colonial waterbirds' prey. View Indicator

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