CE/NR797
Lab: Fisheries
and Global Change
[Prepared
by R. Fortner for ¡§Digital and Field
Techniques for Coastal Environment Studies,¡¨ 7/02]
This laboratory will take a brief look at some very complex
interdisciplinary issues. Some parts will be integral to the class time on
July 12 and 15, and others are independent.
Objectives: With the exercises in this lab, students will be
able to
-
Examine changes in commercial and sport fisheries over the years
-
Analyze presence and strength of factors that could potentially cause fishery
changes
-
Evaluate wetlands change, overfishing, global climate change and invading
species as factors affecting fisheries.
Procedure:
1. Downeaster
Alexa. [Published in Mayer, Fortner & Murphy, 1993, Activities
for the Changing Earth System.
Columbus, OH: The Ohio State University Earth Systems Education Program]
a.
Data in this activity have been simplified to focus on reproductive
potential of different sizes of fish. You will consider a sample of data
(100 fish) and extrapolate to the total fishery. Work out the potential changes
to the fishery (Chart A) that could arise if size limits were imposed. How many
fish should be caught? Explain what would be a sustainable yield of striped
bass.
b.
Update or replace the charts in ACES with information through 2000 using
the SB2001.pdf file. What are the
factors seen by the National Marine Fisheries Service as the greatest effects on
the fishery? Which, if any, of the factors could be turned into digital formats
for greater information or analysis?
2.
Great Lakes fish and environmental changes
a.
Read GLIMCES p. 81-2 as background on the
issue of climate change impacts on spawning. Use a bathymetric map of the
western basin of Lake Erie and add GIS themes to identify the new shoreline if
lake levels dropped 1-3 meters. Work with classmates to see how each of the 14
species would fare with the new conditions. In other words, complete the activity
(parts 1 and 2) that begins on page 83.
b.
You have heard about the decline in walleye and perch in Lake Erie and
some of the speculations on causes. Choose one kind of sport fish in the lake
(walleye, yellow perch, smallmouth bass, lake trout) and document the catch
reported by the Ohio Division of Wildlife or the GL Fishery Commission for the
years in which records are available. What seems to be the trend in fishing for
the species? Is the catch improving or declining in numbers, fish size, or other
measures? Use Status2001.pdf.
Other resources are available on the web page for July 15.
Analysis:
Design
an investigation (digital or field) to examine the impact of two different
factors that are potentially responsible for the decline or other change in the
sport fishery for one of the Great Lakes species. Tell what your objective is,
how you would proceed to investigate the factor and how you would determine when
you had results.