Commercial fishing nets often trap unprofitable animals in the process of catching their target species. In the following activity, students will experience the difficulty that fishermen experience while trying to isolate a target species when a variety of animals are found in the area of interest. The class will then discuss the large magnitude of this problem. Students will practice their data acquisition and analysis skills, through the collection of data and processing of this information to deduce trends on 'target species' distribution. Students will conclude the activity by discussing how bycatch impacts their lives and whether or not it is an important environmental issue that we need to address. As an extension, students can use their creativity and innovative skills to design nets or other methods, theoretically and/or through hands-on building, that fisherman could use to help avoid bycatch.

Bycatch, the unintended capture of animals in commercial fishing gear, is one of the hottest topics in marine conservation today. About 25% of the entire global catch is by-catch This surprisingly high level of by-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 will analyze the significance of by-catch in the global ecosystem and propose solutions to help reduce by-catch Students will become familiar with current attempts to reduce fishing mortality of these animals, such as acoustic alarms, breakaway links, gear modification, and time-area closures. Through the associated activity, the problems that managers face today will be reinforced and students will be stimulated to brainstorm about possible engineering designs or policy changes that could reduce the magnitude of by-catch

In the previous lesson, students learned about the issue of by-catching by fisheries and how it affects marine habitats. Dolphins are one of the main species affected by by-catching While dolphins can use echolocation to identify the location of many objects, they have difficulty identifying nets, and thus can be caught in them by accident. Students will 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' echolocation ability when developing by-catch avoidance methods. In this activity the students will experience a simulation of echolocation and use it to walk along a path while blindfolded.

Bycatch can be defined as the act of unintentionally catching certain living creatures using fishing gear. A bycatched species is distinguished from a target species (the animal the gear is intended to catch) because it is not sold or used. Marine mammals (whales, dolphins, porpoises), seabirds, sea turtles and unwanted or undersized fish are some examples of animals caught as by-catch The incidental capture of these animals can significantly reduce their populations. The most well known example of by-catch may be the unintentional mortality of spotted and spinner dolphins in the tuna fishing industry. "Dolphin-Safe" tuna was a result of this interaction (Be prepared to discuss how this came about with students, as it is something close to their daily lives). One important aspect to consider when discussing this issue is that laws protect some of the animals caught as by-catch (Marine Mammal Protection Act and Endangered Species Act). In this lesson, students will first be shown pictures of entangled marine animals and will discuss the definition of by-catch This will lead to discussions on why by-catching exists, how it impacts specific animals as well as humans, whether the students believe it is an important issue, and how by-catch can be reduced.

In the previous lesson, students learned about the issue of by-catching by fisheries and how it affects marine habitats. Dolphins are one of the main species affected by by-catching Dolphins use echolocation to identify the location of objects in the water, but they have difficulty identifying nets, and thus can be caught accidentally. Students will 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' echolocation ability when developing by-catch avoidance methods. In this activity the students will experience a simulation of echolocation and use it to walk along a path while blindfolded.