Counting/Estimating Populations

Counting Populations How do you think scientists calculate the population of wildlife, such as deer, fish, penguins, and other animals?

Why is counting a population important? Knowing the size of a population of animals is extremely important in making environmental decisions that would affect the population, but estimating the size of wild populations is very difficult.

Why is counting a population important? In the case of whales, the task is very challenging. Estimates of the number of Minke whales, for example, have differed by as much as a factor of 10. Deciding whether to allow hunting of Minke whales, based on population estimates that are too high, could lead to extinction of the species. Basing a decision on a low estimate could ban hunting of Minkes by people who rely on them for food.

Methods There are two main methods that we will look at: 1. Mark & Capture (aka catch & release) Scientists catch the animal, mark them, then release them. At a later time, animals are caught from the same population and observe how many are marked. A calculation is used to estimate the population. (Lincoln Index)

Methods 2. Line-Transect Survey Scientists will observe every animal seen while traveling in a straight line. This is usually used for land animals but has been recently applied to counting whales.

Methods https://www.youtube.com/watc h?v=7nr9rQpm2A4 https://www.youtube.com/watc h?v=5DR50IgvE7g

Methods: Set up a t-chart in your notes like the one below: Method Pros Cons line transect survey mark & capture