Long Island Sound –
By the Numbers

• Area of the Long Island Sound 1,320 square miles
• Area of the drainage basin or watershed 16,820 square miles
• Average Depth 63 feet (60-120 feet)
• Water Volume 18 trillion gallons
• Length of Coastline 600 miles
• Salinity range at the western end 23 parts per thousand
• Salinity range at the eastern end 35 parts per thousand
• % of fresh water that comes from three major rivers 90%
• Avg. winter and summer water temperatures (2011) 37°F winter/69°F summer
• No. of tides each day (greatest tides in the west) 4 tides (2 high, 2 low)
  
• Population living within 50 miles more than 23 million people
• Estimated value to the local economy per year $8.91 billion  (2011 dollars)
• No. of finfish species found in the Sound More than 120 finfish species
• No. of tropical species that stray here seasonally 21 tropical species
• No. of species that spawn in the Sound at least 50 species