Background Information:

A sea lamprey is a parasitic fish that is native to the Atlantic Ocean and many of its tributaries.  The sea lamprey invaded the Great Lakes region in the early 1900’s via shipping canals.  The sea lamprey feeds on fish by attaching to the host with a sucking disk and sharp teeth.  The sea lamprey will drain the body fluids from the host fish, ultimately resulting in the death of the fish.  Efforts to control the sea lamprey population have been in effect since the early 1960’s.  Early efforts to control populations began with mechanical and electrical weirs and the use of a lampricide, a chemical toxicant.  Today, these efforts are combined with new methods such as low-head barrier dams, stream velocity barriers, electrical barriers, and sterilization of adult male sea lampreys. 

 

Click here to download a printable student worksheet. 

 

To get started, do research about sea lampreys and sea lamprey control on the web:

http://www.iisgcp.org/EXOTICSP/lamprey.htm

http://www.glfc.org/sealamp/how.asp

 

Decision analysis is a scientific way of assessing alternatives, judging alternatives, and forecasting consequences of the alternatives.  As a team, you will follow the following series of steps:

 

Step 1 = Define the Problem;

Step 2 = identify and agree upon management Objectives to achieve; assign weights to the objectives;

Step 3 = determine probable Alternatives

Step 4 = forecast Consequences of the options; and

Step 5 = consider the Tradeoffs and use the model to rank each option

  

Procedure:

 

1.     Step 1 = Define the Problem. What is the problem we are trying to solve? In this activity, the problem is defined for us (hint, see the title!)

 

2.      Step 2 = identify the Objectives. What are the goals? What should the outcome include? 

In assigned groups establish 4 objectives.  Management objectives are those  actions which are specifically related  to the problem, can be measured, and have a specified amount of time.  The objectives should be guidelines which will be used to choose an alternative.  

 

Sample Objectives	to achieve target sea lamprey population levels of 5 mating couples per spawning area to maximize economic values of reduction options
Objective 1
Objective 2
Objective 3
Objective 4

 

3.      Of the objectives written, weigh the objectives in terms of importance and value.  Assign a value of 1 to 10 for importance with 10 indicating the most important.  Even though there are only 4 objectives, use a 10 point scale (for instance, one objective might carry much more weight than another. Rating them on a scale of 4 might not show that one objective is a lot more important). Take into consideration tangible and intangible values. 

 

 

 

 

 

 

 

4.      Step 3 = determine probable Alternatives. Read about each population reduction method (these are the alternatives). Information on sea lamprey control methods can be found at  http://www.glfc.org/sealamp/how.asp (also on this page, see fact sheets for different control methods). The control methods you will evaluate for this activity are:

      Alternative 1 = No Future Treatment
Alternative 2 = Barriers
Alternative 3 = Sterile Male Release
Alternative 4 = TFM

 

      

5.      Step 4 = forecast Consequences of the options. What can happen in each case? Evaluate each method (alternative) for possible consequences.  

 

 

      List 4 consequences for each control method (alternative). You may have to think about other possible consequences than just what is listed on the web site and fact sheets! What are the possible consequences for no future control methods? 

 

 

	Possible Consequences
Alternative 1: No Future Treatment	1. 2. 3. 4.
Alternative 2:  Barriers	1. 2. 3. 4.
Alternative 3: Sterile Male Release	1. 2. 3. 4.
Alternative 4: TFM	1. 2. 3. 4.

 

6.      Step 5 = consider the Tradeoffs. What is negotiable? What parts of the alternatives are you willing to give or take? Are some consequences negotiable? 

 

7.   As the final step, evaluate each option of sea lamprey reduction and decide which reduction method you would choose based on your objectives and possible consequences.  Taking into account all of the steps above, create an Objectives by Alternatives Matrix (see below) to see how well each alternative meets your objectives. Using the table below, fill in your objectives, and then rate how well each alternative meets your stated objectives (for example, how does alternative 1 meet objective 1?). Keep in mind the consequences for each alternative, and the tradeoffs you are willing to make.

 

 

     You can use a scale of 1 to 5, where 1=not at all, 2=not very well, 3=somewhat, 4=pretty well, 5=very well

 

 

[write Objectives in below]	Alternative 1 No Future Treatment	Alternative 2  Barriers	Alternative 3 Sterile Male Release	Alternative 4 TFM
Objective 1	.	.	.	.
Objective 2	.	.	.	.
Objective 3	.	.	.	.
Objective 4	.	.	.	.

 

 

8.   Now you have numerical results of your decision.  Finalize the process by subtracting the consequence value from the objective value.  This will give you a number that you can compare to the other reduction methods.  The method with the highest value indicates your choice of the best reduction method to use.

 

Return to list of Lessons