Department of Environmental Conservation

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On the Trail of the Hudson's Migratory Fish

Lesson Plan

Students will practice addition and subtraction skills by tracking the movements of migratory fish of the Hudson River estuary.


Students will solve word problems that require them to:

  • add and subtract using data from tagged fish to calculate distance traveled, elapsed time, and growth;
  • understand the life cycle of anadromous fish.

Grade level:

Elementary (Grades 3-5)

Subject Area:

Math, Social Studies (Geography), Science

New York State Learning Standards:

Mathematics, Science, & Technology Standards 3, 4


  • Use whole numbers to identify locations and measure distances.
  • Add and subtract whole numbers.
  • Apply mathematics in real world settings.
  • Reason mathematically.


Preparation time: 5 minutes
Activity time: 45 minutes


Each student should have:


Scientists attach numbered tags to fish to track their travels and growth. Anglers who catch tagged fish contact the scientists using information on the tags. The data they provide can be used to determine how far and how fast fish travel and how quickly they grow.

Striped bass, Atlantic sturgeon, and American shad are born in the freshwater part of the Hudson but eventually swim out into the Atlantic Ocean. They spend most of their adult lives at sea, returning to the river only to spawn (lay eggs). We think of them as "our" fish, but their visit here is just one piece of their long-distance migrations. Fishes with this life cycle (living in the ocean but entering fresh water to spawn) are called anadromous fishes.

Distances on 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. In preparation for this lesson, have students do the Readings in Hudson River Natural History lesson titled "Atlantic Sturgeon of the Hudson River."
  2. Discuss the concept of migration and the anadromous life cycle of many Hudson River fish.
  3. Introduce the Hudson River Miles system; show students the Hudson River Miles map.
  4. Go over the worksheet with the class or hand out as an in-class or homework assignment.
  5. Some questions require students to add distance between a point upriver and New York to distance between New York and another site along the coast. A U.S. map is helpful here.

Vocabulary List and Answer Key:

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


  • Have students share answers to questions from worksheets, or collect and grade sheets.
  • Make up similar elapsed time/distance/growth problems for quiz.
  • Extension: Cut out paper tags of different colors to represent tagged fish.


  • The Hudson River Foundation's striped bass tagging program posts results. Use the links leaving DEC's website on the right side of this page to visit the Hudson River Foundation's web pages.
  • Illustrations and information about the fish described in this activity can be found on the New York State Department of Environmental Conservation's Freshwater Fishes page.