St Louis River Estuary: The stories and the science

Barker's Bug Hunt

The Search for the Rat-tailed Maggot

This is a geocaching-based quest designed to teach about the use of aquatic insects and other macroinvertebrates as indicators of water quality. It is a team-based exercise in which groups of 2-5 people visit sites on Barkers Island and search for geocache containers. Each container contains a picture of an 'indicator' insect - players identify each insect and use their collection to calculate a water quality score for their site.

The sites represent a range of site quality, from a shallow lagoon area with considerable goose activity to open rocky shoreline. The quest concludes with players comparing scores and discussing reasons why that particular aquatic community was present. This quest is based on the Riverwatch program – a nationwide citizen-science program designed to promote and inspire stewardship of aquatic ecosystems.

Your Location

Barkers Island, Superior, Wisconsin

Quest Setup

Figure 1. Location Map. Click to zoom.

Figure 1. Location Map.

The quest uses a set of ten film canisters at each site (50 total), each containing a line drawing of an insect. The set can be checked out from the LSNERR headquarters on Barker’s Island.

The insects are organized into groups based on their tolerance to polluted waters, as follows:

  • Goose Beach – Very Tolerant
  • Swimming Beach – Fairly Tolerant
  • Whaleback – Moderately Intolerant
  • East Bayside - Intolerant
  • West Bayside – Intolerant

Step 1

In advance of the quest, hide 10 containers within 20 ft of the GPS coordinates at each site. The containers should be placed so they are relatively easy to find – hanging from branches or at the base of large rocks. Players should plan to spend about 15-20 minutes searching to find the containers and identify the indicators, using the supplied identification key.

Step 2

Load the site coordinates into a GPS unit; if necessary, show the players how to select and navigate to a site on the GPS.

  • Goose Beach – N46° 43.243 W92° 03.649
  • Swimming Beach – N46° 43.175 W92° 03.554
  • Whaleback – N46° 43.366 W92° 03.823
  • East Bayside - N46° 43.196 W92° 03.428
  • West Bayside – N46° 43.236 W92° 03.500

Step 3

Supply the teams with the bug identification key and data sheets, and provide instructions on how the quest works. Give the teams a time limit (e.g. spend no more than 20 minutes for each site) and allow time for discussion afterwards. Send them off! If there are multiple sessions, leave the containers in place, otherwise have the last team collect them.

Step 4

Wrap-up – have the teams calculate their Pollution Tolerance Index scores and compare the different sites. Some questions to guide the discussion:

  • What was the score for your site? How does your site compare with the others?
  • What did you notice about the site? Does it confirm what the macroinvertebrate indicators have told you?
  • Did you find the Red-tailed Maggot? If so, come claim your prize!