The goal of seining is to give you knowledge of the quantity, variety and stage of aquatic life in a body of water.   The technique for streams is intended to dislodge insects without harming them and have the water flow carry them to your net (the seine).

Water Type:  While you can test all types of water, the best water to start in is a standard riffle with good water flow and fist-sized rocks & pebbles.   This type of stream bottom is the nursery for aquatic insects.   They're able to attach to rocks, spin webs, dig into the substrate and filter nutrients from the water flowing by.

Positioning - 2 person seining 

Pick a spot towards the end of a riffle (or even the flat after a riffle) and face upstream.   Get your feet set and spread the seine out in front of you with the net toward the water.   Place the bottom of the seine firmly on the stream bottom.   Always take a "free-drift" sample as your first catch.   Just leave the seine in the water for 2-3 minutes to see what is naturally drifting in the stream.   Typical seining activity shows what is in the water, substrate, etc.   A free-drift check shows what is available within the water column to actively feeding trout.   This technique will be more successful in capturing emergers and cripples during a hatch.

Following the free-drift sample, have the second person stand ~5 feet upstream from the seine and work to dislodge insects from the stream bottom to send them drifting into the seine.   This can be done by kicking rocks & shuffling the feet.   However, it's much more effective, and you'll get more "intact" bugs if you get your hands wet and gently smooth a hand over the surface of rocks beneath the water to lift insects into the current.   As a finishing touch, try and dig your fingers into the substrate and agitate pebbles, sand and rocks there.

Leave the net in place long enough for the water to pass from the upstream person down to the seine.   When ready to check your results, lift the net out of the water up and away from your body (the bottom of the net should move upstream and towards the surface in an arch, pic 2.)  This keeps the current from washing insects off the seine while you pull it up.

Adjustment for 1 person seining

While a little more difficult, 1 person seining can be just as effective as the two person team.   In this case, position yourself facing downstream with the seine firmly planted in front of you.   Disturb rocks and sediment as best you can with feet, hands, etc.   Remember to lift the seine towards you (pic. 4) when you remove it from the water.   The remaining steps are the same for 1 or 2-person seining.

Reviewing & sorting your catch

In most rivers, you will dislodge more than insects and your seine will come up with twigs, pebbles, grasses, insect parts and hopefully a few live insects.   Don't be fooled if you can't see anything right away (okay, stonefly nymphs are pretty obvious), just wait a couple seconds and look for movement.

Once the insects start to move around you can gently pick them off with forceps.   (above Pic)  Some grip pretty tightly and need a little prodding to get moving before you can grab them, while others immediately start scampering around.   Any light-colored plastic container can be used as a sorting tray.   Place a little water in it and transfer the insects there to get your pick of the crop.   To clean the seine between samples, face downstream and let the current rinse the screen for you.

Don't miss out on the prime viewing opportunity of live insects in the sorting tray.   Insects will exhibit their individual swimming motions, cased-caddis will slowly peek out and begin crawling around, and stoneflies will begin attacking whatever they can !

With smaller nymphs you can place multiple insects in a single vial.   Larger insects store and are viewed better on their own.   Return the remaining bugs to the water !

Preserving the Catch

There are a couple approaches for preserving your catch.

1.  The easiest way is to add denatured alcohol to the vial after the insects are safely in.  Simply fill the vial with the required amount and screw on the lid.

2.  If you don't want to carry a quart of preserving fluid around, you can fill the vials in advance of your trip.  This tends to be messy as the insect displaces solution in the vial or you spill some trying to wrestle that 3rd year stonefly nymph into the vial.

3.  For longer trips away from your vehicle, just store the insects in water until the end of your day.  When you get back to camp/car, empty out the water and replace with preserving fluid.

Whichever method you choose, finish up by tightening the cap, place your new specimen in the BugBagz™ case and head for the next one!

Storing Adults

BugBagz products and the benefits of seining/collection aren't just for nymphs. Adult insects can be successfully stored in the vials as well. Denatured alcohol can still be used, but may distort the color and translucency of wings. It's best to use small pieces of cotton ball moistened with denatured alcohol and stuffed into the vial.

See the Building a Collection page for more info on storing your catch.