Decline in Saltwater Fish Populations (Chapter 7)

Victor Sampson & Sharon Schleigh
Type Category
Instructional Materials
Instructor Guide/Manual , Lesson/Lesson Plan , Activity
This resource, vetted by NSTA curators, is provided to teachers along with suggested modifications to make it more in line with the vision of the NGSS. While not considered to be “fully aligned,” the resources and expert recommendations provide teachers with concrete examples and expert guidance using the EQuIP rubric to adapted existing resources. Read more here.


This is one of 30 lessons from the NSTA Press book Scientific Argumentation in Biology. The lesson engages students in the question: Is our saltwater fish population declining? If so, what policies would be most effective in slowing that decline? The authors point out that the answer to this question is complex and may vary by geographical location. For the purposes of discussion, the lesson is constrained to data from the coastal waters of Florida. The focus of the lesson is on the human impact through both commercial and recreational fishing on six identified fish populations and the ecosystems in which they live. Data and information concerning these fish species found along both Florida coasts (Gulf and Atlantic) is provided. Using a template to construct an argument, students are guided to design and carry out an investigation that will allow them to collect evidence needed to construct an argument defending their claims. As they construct this argument, students build and apply knowledge of interdependent relationships in ecosystems. This lesson is intended for middle or high school students. Teachers are encouraged to refer to the preface, introduction, students’ assessment samples, and the appendix provided in the book for important background on the practice of argumentation and resources for classroom implementation.

Intended Audience

Educator and learner
Educational Level
  • High School
Access Restrictions

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Performance Expectations

HS-LS2-6 Evaluate the claims, evidence, and reasoning that the complex interactions in ecosystems maintain relatively consistent numbers and types of organisms in stable conditions, but changing conditions may result in a new ecosystem.

Clarification Statement: Examples of changes in ecosystem conditions could include modest biological or physical changes, such as moderate hunting or a seasonal flood; and extreme changes, such as volcanic eruption or sea level rise.

Assessment Boundary: none

This resource appears to be designed to build towards this performance expectation, though the resource developer has not explicitly stated so.

Comments about Including the Performance Expectation
The “Curriculum and Instructional Considerations” (p. 97) within the Teacher Notes offer particularly insightful comments about common student misconceptions and how to guide students to deeper understandings and more clear analyses of causality. This lesson asks students whether the saltwater fish population off the coast of Florida is declining and if so, what policies would be most effective in slowing that decline. To help students answer those questions, the lesson provides students with data on the populations of fish off the coast of Florida and with a process for preparing a claim along with evidence and a rationale in support of the claim. This lesson provides an opportunity for students to learn about limiting factors within ecosystems and the complexity of interrelationships within the ocean waters around Florida. Teachers may want to adapt this lesson to other areas that may be of more interest to their students. The National Marine Fisheries Service (NOAA – Office of Science and Technology) provides species information and commercial fisheries statistics for any area you select. States with ocean borders all have their own commercial fishing databases, too. The lesson does not address stable conditions, so teachers may want to ask their students what kinds of conditions would allow marine populations to maintain consistent numbers. Teachers need to be aware of blending the three components of the PE – considering carefully the integration of engaging in argument from evidence, knowledge about interdependence in ecosystems, and an awareness of the causality behind both stability and change. As students construct their arguments, and as they respond to the arguments of their peers, considering each of these components within the context of the others will build understanding. The lesson includes an excellent list of questions for students to help them evaluate their peers’ arguments; these same questions may be used to evaluate their own. The preface, introduction, student assessment samples, and appendix of the full book provide the teacher with background on how to support students in their small group work and facilitate class discussions as they progress through the argumentation cycle.

Science and Engineering Practices

This resource is explicitly designed to build towards this science and engineering practice.

Comments about Including the Science and Engineering Practice
This lesson is centered on the practice of “Engaging in Argument from Evidence” and will engage students in many of the elements of that practice. The final goal of the lesson is for students to produce a written argument that includes appropriate and relevant evidence. The teacher will need to supplement the students' directions with an encouragement for students to consider the ecosystem in which the fish live. Suggestions for doing this are included in the teachers’ notes. The lesson includes a highly guided student investigation in which students are provided with data and background information. Teachers may wish to modify the research aspect of the activity and provide additional data or provide more latitude to students in researching their argument.

Disciplinary Core Ideas

This resource is explicitly designed to build towards this disciplinary core idea.

Comments about Including the Disciplinary Core Idea
There is a recommendation within the teachers’ notes that this lesson should follow discussions of food webs and the complex abiotic and biotic factors that affect the interdependent relationships within an ecosystem. Information is provided for each fish species about prey, predators, habitat, behavior, and pertinent fishing regulations. Students can use population surveys of young as well as catch information to provide evidence to support their claims. This evidence should be highlighted to students as ways to draw inferences about ecosystem functioning in terms of resources. Encourage students to look at how the given species may interact within the same ecosystem. For example, bluefish are opportunistic feeders and will eat other smaller fish. Adult gulf flounder feed on Atlantic croaker. Students can compare the extreme fluctuations in catch of one species and compare it to the fluctuations in other species within the same ecosystem. Catch information can be compared to the counts of young to see the impact of fishing on the different fish species. Encourage students to look to see how these data may be linked. Teachers are advised to read both the Middle School and High School “Curriculum and Instructional Considerations” found within the Teachers’ Notes.

Crosscutting Concepts

This resource was not designed to build towards this crosscutting concept, but can be used to build towards it using the suggestions provided below.

Comments about Including the Crosscutting Concept
In this lesson, students are provided with rich data sets , allowing them to investigate how the specified fish populations may be changing around the Florida coast. With the information provided for each fish species, students can construct explanations to support their claims of how things may be changing or how they may be constant. The comparisons required to answer the question posed will force students to consider factors that affect biodiversity and the relationships among species. Push students to consider what they think may happen next. How do they think fishing may change the functioning of this complex ecosystem? Do they think that a new ecosystem may result?

Resource Quality

  • Alignment to the Dimensions of the NGSS: This and the other lessons in this book were designed to address the three dimensions of the Framework for K-12 Science Education. Teachers are advised to familiarize themselves with Sampson and Schleigh's argumentation framework, suggested teacher behaviors, and assessment approaches before implementing this lesson in the classroom. The lesson resources do not include instructional materials that directly present the core concepts targeted by the lesson. Rather, the teacher will need to provide such instruction prior to or embedded within the argumentation cycle. This lesson is aligned with the intent of the NGSS in that it engages students in authentic and meaningful scenarios and helps to deepen understanding by building on students' prior knowledge.

  • Instructional Supports: The preface, introduction, assessment chapter, and appendix of the full book provide critical instructional support information for teachers who wish to implement this lesson. Successful implementation requires skillful facilitation by the teacher throughout the argumentation cycle. Students and teachers will develop the needed skills over time and with the implementation of multiple argumentation cycles. Teachers will need to supplement the lesson to provide differentiated instruction in the classroom.

  • Monitoring Student Progress: Constant monitoring and feedback are built in to the Sampson and Schleigh's argumentation framework, but they rely on skillful teacher interactions with students. Supportive questioning is critical to student success in this and similar lessons. Teachers should monitor and provide feedback to students as they analyze data, make inferences, develop a claim and initial arguments, present and critique arguments, and draft final written arguments. Teachers can also model and guide students in providing constructive peer feedback. Teachers should consider allowing students to revise and improve final written arguments based on teacher and peer feedback.

  • Quality of Technological Interactivity: This is not a technology-based lesson. Technology may be incorporated in supporting instruction. The materials are all paper-based.