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'em and weep: Problems involving commercial fishing
Mergler, Dan Duncan, Heather Shive
| Our project focuses on the impact
of commercial fishing on the marine environment. Because humans rely
on the sea as an important source of food and resources, they tend
to overexploit its precious commodities. Many species of animals and
plants are endangered due to the destructive nature of methods used
for harvesting. Three major issues threatening marine species include
over-fishing (catching more fish than can be reproduced), habitat
destruction (destroying of the marine enviornment through human use),
and by-catch (unwanted species of marine life that is caught). We
intend to show how fishing practices create these problems and the
effects that they have on fish populations. Through three different
projects, we hope to help children better understand the negative
effects of commercial fishing, raise their awareness of the need to
conserve marine environments, and develop safer and better ways to
obtain ocean resources.
|Best suited for grades 5-6;
ideal class size: 24-27; max: 30-33; min: 12.
description or introduction
The scientific principles
that the activity is founded on.
|This project focuses on issues
of human impact on the marine environment. It specifically investigates
the problems associated with habitat destruction, by-catch, and overfishing.
Through these three activites, students will examine how these practices
impact fish populations and habitats.
Human impact on the marine environment extends to many areas and
is frequently very detrimental. In particular, the fishing industry
affects both target (wanted) and by-catch (non-wanted) species as
well as threatening the stability of many habitats. By-catch includes
any marine organisms which are inadvertently captured and/or killed
through fishermen's activities. It can range from something as small
as a snail to dolphins and porpoises. The proportion of by-catch
species to target species is frequently as great as 100:1. The target
species itself also suffers due to constant overfishing, which disallows
the population to sustain its numbers through reproduction. Because
populations are fished above their maximum sustainable yields (highest
number fishermen can catch of one species without causing population
desecration), they can be driven to extinction over time. Finally,
habitat destruction occurs during fishing processes such as trawling
(form of fishing where a net is dragged on the ocean bottom). Thus
human impact extends far beyond the species that are targeted for
consumption and threatens the entire marine ecosystem.
for the activity
| Two of the three activities are
original ideas. The remaining activity focusing on overfishing was
developed from a lesson plan in Janice VanCleave's book Oceans for
Every Kid (Jon Wiley & Sons, Inc. 1996).
time to do the activity
|These activities take approximately
twenty minutes each for a total time of one hour.
|Familiarize students with the
idea of overfishing and its long-term effects on population sizes
of various fish species
|Help students understand how fishing
practices cause destruction to the marine environment
|Educate students about the problems
involving by-catch and the harm it does to that are not targeted for
the fishing industry
Science Education Standards. (NSES)
content standards that this lesson plan covers:
| Science as Inquiry: Content
Standard A As a result of activities in grades 5-8, all students should
develop abilities necessary to do scientific inquiry and understandings
about scientific inquiry. These activities address standard A by developing
students' abilities to follow scientific procedures. These activities
will provoke further questions pertaining to conservation issues.
|Life Science: Content Standard
C As a result of activities in grades 5-8, all students should develop
understanding of structure and function in living systems, reproduction
and heredity, regulation and behavior, populations and ecosystems,
and diversity and adaptions of organisms. Standard C is addressed
through the comprehension of how overfishing affects commercial fish
populations as well as by-catch populations. Additionally, the activity
involving overfishing includes the subject of reproduction adn the
impact humans have on population size. Ecosystems are addressed by
the activity on habitat destruction.
- dowel rods
- dixie cups
- Swedish fish (candy fish, app. 1-2 lbs.)
Habitat Destruction Activity
- plastic aquarium plants (50)
- different colored jacks (20)
- small fish nets
- sanded/rocky bottom
- various small-sized plastic fish
- marine animals
- large bucket
- dixie cups
Engage: Prior to beginning the three conservation activities,
have students list all the marine species that they consume. In
small groups, allow them to brainstorm about the ways in which fishing
could be harmful to the marine environment outside of these species.
Preparation: Prior to class, the instructor should collect
the required materials and familiarize themselves with the goals
and background information supplied for the activities. Also, it
is recommended to set up each activity in different corners of the
room to avoid congestion. Overfishing activity: collect all materials.
Habitat destruction activity: set up tank with rock/sand and plants,
set up jacks randomly in rocks, fill with water. By-catch activity:
place fish in bucket.
Procedure for the Activity
Activity 1: Overfishing
Each student should tape dowels to table and tape two dixie cups
to ends of rulers á Label one cup "consumption" and one cup "population"
á Ruler acts as balance on dowel rod á Each student starts out with
20 fish á Each student is allowed to choose however many fish they
want in the consumption cup á For remaining fish, multiply that
number by growth rate number 1 (given by teacher)...this represents
the number of offspring produced by remaining population á Place
new fish into "population" cup á Compare to see if it is balanced
á Repeat with different growth rates
Activity 2: Habitat Destruction
Each jack is considered a target species and is worth 10 points
á Each student will get 2 minutes to grab as many jacks as possible
with the fish nets á Each plant knocked over is valued at -5 points
á Determine final scores
Activity 3: By-catch
Each student receives a cup á A large bucket containing the fish
is placed above the students' heads á Bucket should contain 20%
target species compared to number of bycatch á Each student scoops
out a cupful of plastic fish á One specific fish (target fish) will
be valued at 5 points á The remaining species (by-catch) will be
valued at -2 points á Determine final scores
work sheets, additional web pages
for discussion or conclusion
|How does reproduction rate
relate to maximum sustainable yield?
|Is it possible to obtain the
target species without disturbing the environment?
|Is the number of target species
caught worth the price paid for the amount of by-catch?
|Are there better ways to obtain
target species than the ones represented in the activities?
|The students should be able
to discuss the pros and cons that are associated with fishing practices.
Understanding reproductive rate and maximum sustainable yield can
be tested by quizzes on calculating population increases or decreases
based on the reproductive rate.
activities which relate to and extend the complexity of the experiment.
|Students can brainstorm
about less destructive methods for fishing and possible ways to prevent
by-catch. Students can investigate which marine animals are endangered.
Students can research the methods that are used to obtain their favorite
types of seafood.
A web address with information on the topic of the activity.
|Castro, Peter & Huber, Michael
E. Marine Biology. McGraw-Hill, 2000.