|Copyright © 2009 Tim Loh|
Aquatic Sampling- Bottle traps
Calgary, Alberta, Canada
Bottle trapping is an effective method used in capturing/collecting larger aquatic beetles, primarily dytiscids and hydrophilids. Many of these beetles are strong swimmers and especially the large ones (Dytiscus, Cybister, Hydrophilus, and others), can easily evade a dipnet.
A bottle trap is quite simple to make and requires the following materials:
1) An empty soda bottle (1-4 L is ideal)
2) tape, staplers, or other appropriate sealing material (eg. silicone)
3) string and a float
4) bait (optional)- usually pieces of meat or fish
5) scissors/pen knife
1) Trim the top 1/3 of the bottle off (down to the shoulders), invert the top and nest it in the bottom 2/3s of the bottle
2) Using an appropriate sealant, tape, or staplers, attach the inverted top to the rest of the bottle
3) tie one end of the string around the bottle and the other around a float (in this case, an empty, closed, plastic tube was used); ensure that there is sufficient distance between the trap and the float such that the float stays on the water surface and the trap stays on the bottom substrate.
4) Place the bait in the trap
And done! Now off to the pond (see other images for further explanations).
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