EEL-ectrofishing with the Canadian Wildlife Federation

One late summer night in August, 2018, I was invited by my friend, Steve Woods, a biologist with the Canadian Wildlife Federation (CWF), to photograph a night of boating on the Ottawa River for a research activity of the local eel population.

I accepted the invitation in a heartbeat and was also keen to take on the challenge of photographing in the dark in a small boat bouncing around on a river.

American Eel numbers have declined by over 99% in their Ontario range from their historical abundances. The number one threat to their decline is barriers along their migration routes.  The Canadian Wildlife Federation, in partnership with Carleton University and Energy Ottawa, are tracking the downstream routes eels use when passing through the Chaudiere Falls Generating Station in Ottawa.  Tracking of the eels is achieved by catching them upstream from the falls, surgically inserting small transmitters (tags), and monitoring them by way of radio receivers installed around the falls.     

Energy Ottawa has gone above and beyond their call of duty and installed a downstream bypass channel for eels at Chaudiere Falls. This research is testing the effectiveness of the channel.  Without the bypass channel, heaps of eggs and potential babies are lost if they get chopped up by the turbines.

I met Steve and the two biology students at the Shirleys Bay Boat Launch at 9pm.  After loading the boat and blinding them with my flash we were ready to catch some eels. The boat looks like a spaceship but is uniquely adapted for electrofishing.  For the electrical enthusiasts, the boat and the metal spaghetti strands dipping into the water are the cathode, and the booms that look like inverted metal umbrellas are the anodes.

With electrofishing, any fish about 10 feet from the boat will swim towards the anode where they can be caught with insulated dipnets ready at the bow.  It sounds mean to say that you electrocute fish to catch them, but don’t worry, when done properly, the fish don’t get hurt; it only stuns them for about 30 seconds! Electrofishing is the most effective way to sample a large area., You can cover large stretches of the river (>5 km) in one night using electrofishing.

Below, Steve attaches an anode to the insulated boom before the boat is launched.

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Steve readies the control box from which the electric current is applied between the cathode and the anode.

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Look how awesome the boat looks with the fixed electrode arrays hanging down from the bow, and the 2 deployable anodes on their insulated booms.

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Once we were all onboard, the 2 anodes were deployed and tested with the control box.  Steve enters information for the log and sends a text message off to his safety contact at CWF to confirm the night’s launch.

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Steve adjusts the intensity of the electricity here to make sure the amps are at the right level.

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Netters at the helm waiting for their eel.

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Eels are endangered in Ontario which makes them a tricky study subject.  And because biologists don’t see many eels over the course of the summer, they grow attached to the ones they find and name them.  Below, Cassy with Murieel (Steve reely :-) hated that name and tried to get me to change it to a name he liked more (Racheel), but I wanted to preserve the authenticity of the night!)

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Bringing the eel back to shore for surgery.

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Checking to see if they caught the eel before.  They put electronic tags (PIT tags) in each one they catch, and can tell if they have caught it before. It’s the same kind of tag that dogs get when they are microchipped.

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Bringing the eel ashore, note the fully deployed metal spaghetti strands (anodes) for dissipating the electric current. 

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Cassy monitoring the eel prior to anesthetic being administered.

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Measuring out the anesthetic to make her go night night.

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Putting the anesthetic in the cooler.

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Recording catch location and other data like tag numbers while we wait for the eel to go under.

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Making solutions to sterilize the surgical tools.

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This tag is surgically inserted into the eel.  The tag sends out a ping every few seconds.  The pings are picked up by receivers that are set up all around the dam.  The receivers are all triangulated so they can tell the exact path that the eel takes when going over the dam. They also have receivers downstream up to Petrie Island area. If they get picked up all the way out there, they assume they survived.

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Measuring the length of Murieel.

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Taking a sample for future DNA analysis.

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Taking head width measurements.  Steve also took head height and pectoral fin lengths.

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This is a head height measurement.  Measurements are basically to see at what size do eels start to head back to the sea to breed.

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Steve is writing out a card with the eel ID so he can take a picture of her to measure her eye later using software on a computer. It’s part of the body measurements to see when they move out.

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Team work makes the dream work! They all collaborated to take a weight of her!

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Giving her fresh, oxygenated water to wake her up after the surgery.

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Pretty happy with the success for the night and driving her back to where we caught her.

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A very quick photo op before releasing Murieel at the catch location.

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Many thanks to Steve Woods for extending me this great opportunity to photograph and blog on this important research activity.

To check out the other conservation work the Canadian Wildlife Federation is doing be sure to check out their website and blog.

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One thought on “EEL-ectrofishing with the Canadian Wildlife Federation

  1. Patricia Mossman

    Very interesting Robbie. I knew very little about electric eels.

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