Marine snails as biological suction cups?

We all have been stressed out at one time or another, it’s a part of life. A couple weeks ago our class set out to see how multiple stressors would affect the frilled dogwinkle or dogwhelk (Nucella lamellosa), a marine snail found around the shores of Vancouver.

For us humans, common stressors can include work, school, or going to the dentists but for the dogwhelk things are a little bit different. Living in the intertidal areas of Vancouver, these snails are exposed to stressors such as changes in water and air temperature, the amount of time exposed out of water and salinity (how much salt is in the water), to name a few. When these factors change it puts stress on the intertidal animals, just like how our levels of stress change depending on what is going on in our lives. Stress can affect various things in these snails such as their behaviours and activity levels.

Frilled dogwhelks and their yellow coloured eggs found in Stanley Park. Taken by Emma Girard on January 30, 2022.

How to stress snails out…

Today I am here to tell you how not to stress out a snail, by telling you how my class and I did stress out these snails. The two stressors which we were investigating were temperature and salinity. We wanted to know if temperature and salinity, when paired together, caused more stress in the snails overall.

For the experiment, we first super glued a bead to the snail’s shell and fed a fishing line through the bead. Then, we waited for the snail to attach to the bottom of the tank, once attached we added weights to the free end of the fishing line. Next, we waited like kids in a candy shop fascinated with what was about to happen.

Frilled dogwhelks with their beads attached ready to be stretched. Taken by Emma Girard on March 7, 2022.

Gradually, the snails began to be pulled up from their shell and were stretched out to the maximum with only their foot, a muscular body part attached to the tank. These snails turned into “biological suction cups” and fought against the stress of the weight. Over time the snails got to their breaking point of too much stress and detached from the tank going flying into the air. See below the video of our snail holding on for dear life.

The frilled dogwhelk vs 351g of weight. Disclaimer: No snails were harmed in the making of this video. Video footage by Ruby Burns on March 7th, 2022.

Some of these snails were able to hold between 200-375g before detaching which is a crazy amount of weight! We found that neither temperature or salinity had an effect on the strength of the snails; I guess they were not stressed out enough, should have given them a math midterm! As our climate changes, we will likely see stressors having a greater effect on intertidal creatures, even leading to death in some of these animals and plants.

In order to not stress out these marine snails, my suggestion would be to maybe not attach a snail to weights and see how much it can hold, as even these “biological suction cups” have to give up eventually.  

If you want to learn more about the stressors of the intertidal zone, check out this article about how the past summer heat wave in Vancouver stressed out intertidal organisms: https://www.theatlantic.com/ideas/archive/2021/07/billions-victims-heat-dome/619604/