K-2

Blue Crabs

Implement this lesson:

Use this lesson when discussing animal ecosystems, habitats, or other environmental TEKs. This lesson can be used as part of a larger local theme i.e. Oceans Week. It can also be used for a crab themed day. The duration of this lesson can vary based on student and teacher needs.

Learning Objective:

Students will be able to learn about one of the most common animals found in local saltwater habitats, the blue crab. They will create an art project using their knowledge.

Texas Essential Knowledge and Skills (TEKS)

Science TEKS 

K.10(B)  identify basic parts of plants and animals  

K.10(A)  sort plants and animals into groups based on physical characteristics such as color, size, body covering, or leaf shape 

1.9(B) analyze and record examples of interdependence found in various situations such as terrariums and aquariums or pet and caregiver  

1.10(A)  investigate how the external characteristics of an animal are related to where it lives, how it moves, and what it eats

2.10(A) observe, record, and compare how the physical characteristics and behaviors of animals help them meet their basic needs   

2.10(B) observe, record, and compare how the physical characteristics of plants help them meet their basic needs such as stems carry water throughout the plant   

 2.10(C) investigate and record some of the unique stages that insects such as grasshoppers and butterflies undergo during their life cycle 

ELA TEKS

K.3(B) use illustrations and texts the student is able to read or hear to learn or clarify word meanings

K.5(B) generate questions about text before, during, and after reading to deepen understanding and gain information with adult assistance 

K.5(E) make connections to personal experiences, ideas in other texts, and society with adult assistance 

1.9(D) recognize characteristics and structures of informational text, including: (ii) features and simple graphics to locate or gain information

1.6(C) make and correct or confirm predictions using text features, characteristics of genre, and structures with adult assistance 

2.6(B) generate questions about text before, during, and after reading to deepen understanding and gain information 

2.6(I) monitor comprehension and make adjustments such as re‐reading, using background knowledge, checking for visual cues, and asking questions when understanding breaks down 

Overview 

There is a created slideshow for anyone to follow.  It is broken into days.  At the end of the slideshow there is informational slides that should read before teaching the lesson. 

https://docs.google.com/presentation/d/16nDb8FUmSRAE787FRkgQsAJIky2KfqiLbKfKzqsZBB4/edit#slide=id.p

What is it?
Callinectes sapidus means “beautiful savory swimmer.” It’s more commonly known as the blue crab or Atlantic blue crab. It lives in the western Atlantic Ocean and the Gulf of Mexico but has also spread to other parts of the world.

Importance

  • Blue crabs are very important both for food and the economy in the United States.
  • Major harvesting states include Maryland, Louisiana, North Carolina, Delaware, and New Jersey.
  • In Maryland, it’s the state crustacean and supports the state’s biggest commercial fishery.
  • Some areas, like the Chesapeake Bay, have seen declines in crab populations due to overfishing and environmental problems.

Impact of Climate Change

  • Unlike many species, blue crabs may benefit from warming waters.
    • They are expected to:
      • Breed more easily
      • Survive winters better
      • Spread to new areas along the Atlantic coast
  • However, it’s unclear what effect this population growth could have on other parts of the ecosystem.

Appearance and Features

  • Belongs to the Portunidae family (swimming crabs).
  • Blue crabs can grow up to 9 inches (23 cm) wide.
  • Males vs. Females:
    • Abdomen shape:
      • Males: long and narrow (like the Washington Monument)
      • Mature females: wide and round (like the U.S. Capitol dome)
    • Claw color:
      • Males: blue with red tips
      • Females: orange with purple tips

Where They Live

  • Native to the Atlantic coast from Cape Cod to Argentina, and all along the Gulf of Mexico.
  • Recently found farther north (e.g., Gulf of Maine)—likely due to climate change.
  • Introduced to parts of Europe and Asia (including the Mediterranean and Japan) through ship ballast water.
  • In some places, like Greece, they are now fished heavily and might be overharvested.

Diet and Predators

  • Omnivores – they eat both plants and animals:
    • Thin-shelled clams
    • Worms
    • Small fish
    • Seaweed
    • Dead animals
    • Even other blue crabs!
  • Predators include:
    • Fish like eels, striped bass, and trout
    • Sharks
    • Cownose rays and stingrays
    • Humans

Ecological Role

  • May help control the spread of invasive green crabs (Carcinus maenas).
  • Blue crab numbers tend to go up when green crab numbers go down—especially in the Chesapeake Bay, where green crabs are not common.

Possible Books:

Crabby and Nabby A Tale of Two Blue Crabs by Suzanne Tale

Crabs! An Incredible World Picture Book

Hello! Hermit Crab By Kate Perez

Stalk Eyes A Heroic Fiddler Crab By Ron Sisson

Does a Fiddler Crab Fiddle? By Corinne Demas and Artemis Roehrig

One is a Snail, Ten Is a Crab By April Pulley Sayre and Heff Sayre

Copies for One is a Snail math activity

Procedures: 

  1. Introduce blue crabs by asking what students know about them. Write what students say down in a possible KWL chart.
  2. Watch a video, read a book, or use slideshow to teach students about blue crabs.
  3. Complete one of the various art projects
  4. Read a book on blue crabs
  5. Possibly finish KWL chart

Model of a Blue Crab

  • Paper Plates
  • Modeling clay
  • Paint
  • Pipe Cleaners
  • Scissors
  • Hot Glue
Reference Craft

Sea Glass Art

  • Markers
  • Paint
  • Sea glass art pieces 
  • Glue 
  • highlighter
Reference Craft

Blue Crab Finger Paint Art

Reference Craft

Paper Plate Blue Crab

  • Paper plates
  • Cut up squares of blue construction paper
  • Elmer’s Glue
  • Blue strips of construction paper for arms
  • Possible googly eyes
Reference Craft

Questions to Ask:

  • What do you know about Crabs?
  • Have you ever seen a Blue Crab?
  • How do Blue Crabs move?
  • Do we have Blue Crabs live nearby? 
  • Can Blue Crabs harm us?
  • What 3D Shapes do we see?
  • What are some characteristics we see?
  • What ecosystem does a blue crab live in?
  • What is a blue crabs habitat?
  • What does a blue crab need plants to survive in an ecosystem?
  • Is a blue crab living or non living?
  • What does a blue crab eat? What eats it?

Evaluations:

  • Student participation
  • Student created craft

Extensions:

  • Students write a fiction or nonfiction story about a blue crab
  • Students create their own model of a blue crab using maker space materials
  • Students complete various crab worksheets and lessons

Lesson by: Yessica Azua, Gina Betancourt-More, Tanya Schilinger, Kathleen Pape, Amy Berger