"The Case of the Disappearing Blue Crab" is designed for high school Biology, Aquatic Science, and or Environmental Science students. Students begin the lesson by learning interesting facts about the Blue Crab (Callinectes sapidus) and the Hematodinium dinoflagellate spp. organism to hook them into the lesson. Students then create a graph that illustrates the population decline since the 1940’s and outbreaks of Hematodinium against environmental pressures; which then begs for the question to be asked, "Is Hematodinium the culprit?" Students then explore mock crab hemolymph samples and test for the presence of Hematodinium DNA using Gel Electrophoresis. This provides students the opportunity to apply their knowledge and understanding of DNA and current biotechnology "fingerprinting" methods. Students conclude that Hematodinium is indeed present in their crab sample and are then given the task of creating an information pamphlet or commercial to explain to the public why and how we can save the Blue Crab from Hematodinium.
In vitro life cycle of Hematodinium spp. from Norway Lobster, Appleton & Vickermen 1998. Cross referenced at,
Blue crab from the IMET blue crab project. Photo by Dr. Eric Schott.
This activity captures the students' attention, stimulates their thinking, and helps them to access prior knowledge.
Students will be able to graph data collected from scientific research in order to determine how the crab population has declined and how environmental factors influence Hematodinium outbreaks.
In this section students are given time to think, plan, investigate, collect and organize information.
Students will be able to use gel electrophoresis in order to determine if the Blue crab has been infected by Hematodinium.
Students are now involved in an analysis of their own explorations. Their understanding is clarified and modified because of the reflective nature of the activities.
Students will be able to analyze their gel in order to determine if Hematodinium DNA is present in crab hemolymph. Students will also be able to investigate various biotech techniques available to scientists in order to select the best methods for positively identifying a suspect.
This section gives students an opportunity to expand and solidify their understanding of the concepts and to apply them in a real-world context.
Students will be able to investigate the ecological role of the blue crab and synthesize the harmful effects of Hematodinium on its population in order to create in informational brochure or commercial to increase public awareness.
This performance-based activity helps students to connect all of the pieces of information involved in these lessons.
Students will be able to demonstrate their understanding of importance of the blue crab to the health of the Chesapeake Bay and the dangers of the parasite Hematodinium spp. by writing a formal lab report, creating an information brochure to increase public awareness, and implementing a blue crab population and/or Hematodinium prevalence management technique.