Unit All Caught Up:
Bycatching and Design

Photo under the ocean surface shows dolphins caught in a net.
What can we learn about animals to help us design fishing methods that minimize bycatch?
Copyright © Mission of the US, Geneva, Switzerland http://geneva.usmission.gov/2013/07/16/u-s-implements-trade-ruling-on-dolphin-safe-labeling/


Bycatch, the unintended capture of animals in commercial fishing gear, is a hot topic in marine conservation today. The surprisingly high level of bycatch—about 25% of the entire global catch—is responsible for the decline of hundreds of thousands of dolphins, whales, porpoises, seabirds and sea turtles each year. Through this curricular unit, students analyze the significance of bycatch in the global ecosystem and propose solutions to help reduce bycatch. They become familiar with current attempts to reduce the fishing mortality of these animals. Through the associated activities, the challenges faced today are reinforced and students are stimulated to brainstorm about possible engineering designs or policy changes that could reduce the magnitude of bycatch.
This engineering curriculum aligns to Next Generation Science Standards (NGSS).

Engineering Connection

Students study bycatch from an engineering perspective with the idea to design technological solutions to better address the problem. Many current devices and equipment designed by engineers, such as acoustic alarms, breakaway links, gear modification and time-area closures, are helpful but not enough to alleviate the problem. After learning how echolocation works, students discuss how net designs can be made easier for dolphins to "see" using echolocation and therefore less likely for dolphins become entangled.

Unit Overview

In the first lesson, Caught in the Net, students learn about bycatch—how commercial fishing nets trap large amounts of unintended and unprofitable animals while catching their target species. In the associated activity, All Caught Up, students learn about fishermen's challenge in trying to isolate a target species when a variety of animals are found in a marine habitat of interest. They discuss the large magnitude of the problem, practicing data acquisition and analysis skills by collecting and processing information to deduce target species distribution trends.

In the second lesson, Sound for Sight, the concept of echolocation is introduced as well as how dolphins use this sense to perceive environmental threats in their marine habitat, such as gillnets set by commercial fishing vessels. In the first associated activity, Can You Hear It?, students use marbles and a box made by the teacher to simulate echolocation and experience how much sound can tell us about an object. This helps to illustrate dolphins' use of echolocation, their difficulty in identifying nets, and resulting net entrapment. In the second associated activity, Your Ears Do the Walking, students play a modified game of "Marco polo" to understand the difficulty of using only the sense of sound to observe their environment. They experience an echolocation simulation by walking along a path while blindfolded. What students learn from these activities suggests the engineering approach of taking advantage of dolphins' echolocation ability in the design of bycatch avoidance methods.

Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

See individual lessons and activities for standards alignment.


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Unit Schedule

More Curriculum Like This

Upper Elementary Lesson
Radar: Using Sound for Sight

Students use these concepts to understand how dolphins use echolocation to locate prey, escape predators, navigate their environment, such as avoiding gillnets set by commercial fishing vessels. Students also learn that dolphin sounds are vibrations created by vocal organs, and that sound is a type ...

Upper Elementary Lesson
Caught in the Net: Bycatch vs.Target Species in Ocean Fishing

In this lesson, students are shown pictures of entangled marine animals and then learn the definition of bycatch. This leads to discussions on why bycatching exists, how it impacts specific animals as well as humans, whether the students believe it is an important issue, and how bycatch can be reduc...

Upper Elementary Activity
Let Your Ears Do the Walking

Students experience a simulation of echolation, using the sensory method to walk along a path while blindfolded. Students learn how echolocation works, why certain animals use it to determine the size, shape and distance of objects, and how humans can potentially take advantage of dolphins' echoloca...

Upper Elementary Activity
Echolocation Experimentation: Can You Hear It?

Students drop marbles into holes cut into shoebox lids and listen carefully to try to determine the materials inside the box that the marbles fall onto, illustrating the importance of surface composition on dolphins' abilities to sense materials, depth and texture using echolocation.


After conducting this unit, evaluate students by the following methods:

  • Lesson 1: Assign a journal reflection on the classroom discussion surrounding bycatch and its importance.
  • Activity 1: Evaluate collected data related to their experimental "bycatching" percentages, conclusions drawn and comments on other methods of reducing bycatch (such as a net design, acoustic alarms, etc.).
  • Lesson 2: Assign a journal reflection on how bycatch affects dolphins and how we may prevent it using our understanding of animals. Ask students to describe different gillnets, which are the most useful in preventing by-catch and which they would recommend (depending on cost, efficiency, protection of dolphins).
  • Activity 2: Assign a journal reflection on how their hearing/reacting process worked/failed.
  • Activity 3: Evaluate which surfaces were easiest to identify and how they could tell which surfaces were deeper than others.


© 2013 by Regents of the University of Colorado; original © 2004 Duke University


Aruna Venkatesan, Pratt School of Engineering; Matt Nusnbaum , Pratt School of Engineering; Angela Jiang, Pratt School of Engineering; Vicki Thayer, Nicholas School of the Environment; Amy Whitt, Nicholas School of the Environment

Supporting Program

Engineering K-Ph.D. Program, Pratt School of Engineering, Duke University


This content was developed by the MUSIC (Math Understanding through Science Integrated with Curriculum) Program in the Pratt School of Engineering at Duke University under National Science Foundation GK-12 grant no. DGE 0338262. However, these contents do not necessarily represent the policies of the NSF, and you should not assume endorsement by the federal government.

Last modified: January 13, 2019

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