Department of Environmental Conservation

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Which Fish Where?

Students will use tables and graphs of fish collection data to draw conclusions about where fish live in the Hudson estuary.


Students will use data presented in tables and graphs to:

  • interpret organized observations and measurements;
  • recognize simple patterns, sequences, and relationships;
  • understand environmental factors that influence where fish live.

Grade level:

Elementary (Grades 4-7)

Subject Area:

Math, Science


Mathematics, Science, & Technology Standards 1, 4


  • Interpret data presented in tables and graphs.
  • Observe, identify, and communicate patterns.
  • Present inferences or generalizations indicated by data.


Preparation time: 5 minutes
Activity time: 60 minutes or two 30 minute sessions


Each student should have:

  • Worksheet: Which Fish Where?
  • Hudson River Miles map
  • Pencil


The Hudson is home to a great variety and abundance of fishes. Each kind is found in certain parts of the estuary depending on its habitat and salinity preferences. Some of the river's fish are found only in salt water, seahorses for example, others only in fresh, like sunfish; a few can live in either, like hogchokers.

During DEC's annual autumn Day in the Life of the Hudson River event, students collect fish at sites all along the tidal Hudson and New York Harbor. The tables and graph in the worksheets show data for representative fish species and sites, not all. Most of the fish recorded on Day in the Life are caught in beach seines-curtains of netting with a pole at either end.

Locations along the Hudson are often measured in Hudson River Miles. Hudson River Miles start at the southern tip of Manhattan. This spot, called The Battery, is River Mile 0. The estuary part of the Hudson ends at the Federal Dam in Troy at River Mile 153.


  1. Review the definition of estuary and salt front with the students. To reinforce these concepts, have the students do the math lesson "Tracking the Salt Front" from the Hudson River Estuary Program.
  2. Introduce the Hudson River Miles system.
  3. Go over the worksheet with the class or hand out as an in-class or homework assignment.


  1. Have students share answers to questions from worksheets, or collect and grade sheets.
  2. Find your community or the nearest river community on the Hudson River Miles map. Using the first table in the worksheet (Fish Caught on A Day in the Life of the Hudson River), have students predict which fish they would be most likely to catch at this location.

Answer Key

Available in the pdf version of this teacher's section and in the package that bundles all of the readings.


  • community: a group of living things that interact and are located in one place
  • estuary: a body of water in which fresh and salt water meet
  • fresh water: water that is not salty
  • Hudson River Miles: distance north from the Battery at Manhattan's southern tip
  • salt front: the leading edge of seawater entering an estuary
  • salt water: seawater or other water that contains salt
  • seine net: a fishing net that hangs vertically between floats and weights
  • upriver: towards a stream's source


For illustrations of and information about the fish described in this activity, visit the DEC's Freshwater Fishes web page and the Hudson River Estuary Program's gallery of common Hudson River organisms.

The Atlantic silverside and other fish of salt water are described in the Chesapeake Bay Program's Bay Field Guide. (See Offsite links)

Information about and data from the Day in the Life of the Hudson River Estuary event is available at Lamont-Doherty Earth Observatory's Hudson River Snapshot Day web page. (See Links Leaving DEC's Website)