Ecosystem Targets and Supporting Indicators

Herring Runs at Streams with Upstream Planned Fishway Projects

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.

Show/Hide Table Data

Alewife - Fish Counter
Queach BrookMill BrookGreeneville Fishlift (Shetucket River)
2002-10,0482,288
2003-4,198335
2004-2,385318
2005-1,790586
20063,1139,1312,681
20071,2501422,422
20082,684797535
20093,4779190
201050,6681,239156
20114,4769,080248
201261017,057267
20135639,137713
20141,3951,543787
2015538134502
20161,5144061,456
20173,3088,522735
20187386,9891,653
201938511,232699
- indicates no counting done.
Shad - Fish Counter
Greeneville Fishlift (Shetucket River)
20023,056
20034,573
20041,993
20051,750
20061,981
20072,453
20081,966
20092,168
20102,461
2011992
20123,312
20133,800
20142,248
20151,919
20162,669
20171,910
20181,216

WHAT ARE THESE SPECIES?

River herring is a collective term for the Alewife, Alosa pseudoharengus, and Blueback herring, Alosa aestivalis, two anadromous fish species that are related to the American Shad. Anadromous fish migrate from the ocean to rivers to spawn.  The coastal range of the Alewife extends from northeastern Newfoundland to South Carolina, while that of the Blueback Herring extends from Nova Scotia to Florida. Both species undertake upriver spawning migrations during spring.  The American Shad, Alosa sapidissima, is the largest of the herring family and is a favorite Connecticut River sportfish. It also undertakes upriver spawning migration during spring. The historic range of American Shad was from the St. Lawrence River to Florida. Shad are still distributed throughout their historic range but shad are most abundant in east coast rivers between Connecticut and North Carolina.

WHAT DOES THIS INDICATE?

River herring and shad are important to our freshwater, marine and estuarine ecosystems because adult herring and their young provide food for a variety of predators including freshwater gamefish, marine gamefish, osprey, bald eagle, harbor seals, porpoise, egrets, kingfishers, and river otter. Historically, river herring runs into Connecticut rivers and streams numbered into the millions; however, runs have been declining steadily in recent decades. To help restore river herring populations and other anadromous fish, CTDEEP has built fishways at dams, removed dams, and widened culverts to allow fish to bypass barriers to find habitat upstream to spawn.

STATUS

This group of streams has one fishway where fish are counted.  The amount of available habitat upstream of the fishway is expected to increase due to future fish passage projects (e.g. there are upstream dams that will have fishways in the future).  Because of this, the number of fish returning in the future will likely increase regardless of survival at sea.  These numbers can be used as an index of how restoration is progressing for each watershed over time.

These Alewife counts were mixed in 2018: Greeneville was up slightly, Mill Brook was down slightly, and Queach Brook was down significantly.  This kind of ‘mixed signals’ has been typical of Alewife runs in Connecticut in recent years.  It is believed that all runs are depressed since the mid-1980s and these ups and downs are relatively minor fluctuations in the respect to the Big Picture, perhaps reflecting the fact that in some years a few more fish by chance slip past nets in the ocean than those destined for another stream, yet this trend could be reversed the following year.

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