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Fish Communities in the Hudson

Lesson Plan

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


Students will use data presented in tables to:

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

Grade level:

Elementary (Grades 3-5)

Subject Area:

Math, Science


Mathematics, Science, & Technology Standards 1, 4


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


Preparation time: 5 minutes

Activity time: 30 minutes


Each student should have:


The Hudson is home to a great variety and abundance of fishes. Each kind has its habitat and lifestyle preferences. For example, the Hudson is an estuary in which salty ocean water and fresh water mix. Some of the river's fish are found only in salt water, others only in fresh; a few can live in either. Some fish swim in schools; others tend to keep to themselves. Given these preferences, fishes occur in communities-fishes of freshwater shallows, for instance.

During DEC's annual Day in the Life of the Hudson River event, students collect fish at sites all along the tidal Hudson and New York Harbor. Of the 200+ kinds of fish found in the Hudson and its tributaries, students have caught about 50 over the years; the worksheet's tables show data for a handful of these species. To simplify, data from sites less than one mile apart were combined, and many sites were left out. Most of the fish recorded during Day in the Life events 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 concept of estuary with the students.
  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.


  • Have students share answers to questions from worksheets, or collect and grade sheets.
  • Investigate one species of fish further, using the resources listed below.

Answer Key

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


  • average: equal or close to an arithmetic mean
  • community: a group of living things that interact and are located in one place
  • fresh water: water that is not salty
  • Hudson River Miles: distance north from the Battery at Manhattan's southern tip
  • leading edge: line marking a beginning or end
  • salt front: the leading edge of seawater entering an estuary
  • salt water: seawater or other water that contains salt
  • school (of fish): a group of fish swimming together
  • seine net: a fishing net that hangs vertically between floats and weights
  • species: a class of living things of the same kind and same name
  • 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 Estuary Program's gallery of Hudson River organisms.

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

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)