Salmon, Lampreys, and Minnows—OH MY! Nighttime Snorkel Surveys

It was 11:30 at night.  The search was put on pause as someone re-adjusted their gear.  Wanting a break and to see what was going on, I flipped over to my back. Pleasantly surprised, I found myself floating as if I was in the Great Salt Lake:  completely buoyant and relaxed as the current gently pushed against me.  I removed my mask to see if I could spot anyone else.  Although we were all within talking distance, the dense night made the headlamps look like forest sprites teasing in the distance. It was announced we were near the end but would take a quick break to warm and fuel up.  Things can quickly go south when you are swimming in seven degree Celsius water.

I soon felt a gentle pull on my foot as our intern, Michaela, dragged me through the water to the edge.  I thought back on the past couple of hours as the water glided around me.  Skagit Fisheries Enhancement Group (SFEG) has been performing, with Herrera, snorkel service to officially document salmon using Marblemount Slough.  The reason the surveys are done so late at night is because of salmon evolutionary adaptations.  When temperatures begin dropping below ten degrees Celsius, so does salmon metabolism.  This means that salmon are not able to move as quickly and therefore increase their predation risk from other fish, birds, and so on.  So during the winter and early spring months, juvenile salmon reduce the daylight forage and choose to snack at night when predators cannot see them.  As a result, these surveys are done at night so we can achieve the most accurate data.

This would be our second survey for the year.  Due to the very cold nature of the surveys, dry suits, snorkels, waterproof lights, and lots of clothing are required.  Fortunately our local National Park Service let us borrow some of this necessary gear.  Then a group of about five us make our way up the stream.  Two people walk near the shore to keep an eye out for hazards while the other three swim along, looking for and noting fish.  We would switch positions (depending on gear, comfort, and temperature) as people needed breaks and to give everyone a chance to look at the fish. Walking behind the surveyors was treat this time because we saw bats swooping and feasting and heard beavers (we think) slapping their tails.  Though, my favorite part is snorkeling.  There’s nothing quite like swimming in freezing water to suddenly have a baby fish appear.  Salmon, lampreys, and minnows—oh my!

By the time midnight rolled around, we were on our way back to the truck with wet snorkels and plenty film of fish—including a video of a coastal range sculpin.  It was a successful night.  I smile to myself and remember it’s moments like this why I came to the Pacific Northwest.

By WCC Restoration Assistant Taylor Schmuki