Photos of the Long Island Sound

Status and Trends: LISS Environmental Indicators

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

Forage Fish – Open Water/CT Coastline

  • Open Water
  • CT Coastline

Source: CTDEEP Fisheries Division *see data note.

Forage Fish
Open Water Counts per Tow CT Coastline Count per Tow
1988 N/A 138.78
1989 N/A 61.84
1990 N/A 64.45
1991 N/A 109.68
1992 11.36 70.95
1993 12.69 64.71
1994 10.92 57.06
1995 12.71 42.47
1996 13.14 25.85
1997 14.22 32.23
1998 14.37 99.96
1999 20.56 126.89
2000 22.54 146.29
2001 11.91 52.39
2002 16.06 125.35
2003 6.49 206.41
2004 14.52 129.75
2005 14.57 121.74
2006 11.93 59.38
2007 16.06 149.47
2008 13.60 99.64
2009 17.32 106.05
2010 N/A 137.02
2011 10.55 126.73

What are Forage Fish?

Forage fish are small, fast-growing species that provide ready food for larger fish, including game fish such as striped bass and bluefish, and mammals such as seals. Forage fish also includes juvenile stages of larger species which school in large numbers, such as scup, bluefish, and weakfish. Some forage fish inhabit the low marsh and intertidal areas of the shoreline and are food for birds, reptiles, and crabs.

 What does this indicate?

The Connecticut Coastline Forage indicator uses data collected from the CTDEEP Seine Survey, which was established in 1988.  The survey is conducted in September at eight beach sites, from Groton to Greenwich, where six standardized seine-hauls are taken. The index is a composite mean catch/haul of four species: Atlantic silversides, striped killifish, mummichog, and sheepshead minnow.  It is designed as an indicator of forage availability in intertidal and shallow water.

The Long Island Sound Open Water Forage index uses data collected from the Long Island Sound Trawl Survey, which was established in 1984. Survey catch data from spring (May, June) and fall (September, October) Survey cruises of 14 common “forage” species are averaged into a composite mean catch/tow.  These species are key small-sized adults (e.g., blueback herring, butterfish, and menhaden) or the ‘young-of-year’ life stage of abundant schooling species (i.e., weakfish, bluefish, and scup). These species are important forage for larger game fish commonly sought after by recreational anglers (e.g. bluefish, striped bass, and summer flounder).     It is designed as an indicator of forage availability for open water species, and may shed light on trends in the abundance of phytoplankton and zooplankton assemblages needed as their food base as well.


The increasing trend in Connecticut Coastline Forage index since the late 1990s indicates that productivity in the intertidal zone and marshes is good. The stable trend in the Open Water Forage index indicates that the Sound has a sufficient food base to support the wide diversity of resident marine species as well as those that migrate into the Sound specifically because it is a rich feeding ground.


data notes

Counts collected for the fall season of the Long Island Sound Trawl Survey. Data was not available for 2010. The research vessel was out of service during June, September, and October sampling.

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