Question 1
The diagram shows levels of DDT, a pesticide, in an aquatic food web in Lake Kariba, Africa. Numbers represent ppm (parts per million) of DDT in fat tissue.
Outline how the population size of tilapia could be estimated.
The diagram shows levels of DDT, a pesticide, in an aquatic food web in Lake Kariba, Africa. Numbers represent ppm (parts per million) of DDT in fat tissue.
Outline how the population size of tilapia could be estimated.
a. use the capture-mark-release-recapture method
OR
use the Lincoln index method;
b. (random) sample is captured and marked/tagged (in a manner that will not harm the fish/tilapia);
c. captured sample is released (and allowed to mix with general population);
d. (after a period of time) second sample is captured and both the total number and the number of marked fish/tilapia counted/OWTTE;
e. correct formula / description of formula;
3
Marking guidance:
max