Objectives

Construct bootstrap confidence intervals to evaluate the effect of a management regulation on the size distribution of northern pike

  • Using standard error of the bootstrap distribution
  • Using percentile-based methods

Explore the sampling distribution of the Lincoln-Petersen mark-recapture estimator of population abundance (time permitting or on your own)

  • Effect of sampling effort on estimator variability
  • Effect of assumption violations on estimator bias

Growing Northern Pike

Slot limits of either 20 to 30 inches or 22 to 30 inches were implemented on five north-central lakes (all pike within the slot had to be released).


Were they effective?

MN Volunteer Magazine

Histogram of pike lenghts before and after a slot limit was implemented.

Data from Medicine Lake

Medicine Lake

Today’s lab:

  • You are asked to analyze data from 1989 and 1993 (pre- and post-regulation)

  • Your boss wants to know if lengths have increased, and if so, by how much (i.e., she wants an estimate with a margin of error or confidence interval).

Other considerations:

  • Can you conclude any changes were due to the slot limit? I.e., can you assume the regulations caused the changes mean size?

  • Is pseudoreplication an issue? If so, how might you communicate this issue to your supervisor?