The Fastest Way to Measure 934 Tide Pools
A tiny islet in British Columbia is a testing ground for new mapping technology.
You can walk around the treeless shores of Wizard Islet in a matter of minutes. At only a quarter of a kilometer long and 100 meters at its widest, the islet is a low bump on the horizon as you gaze out from Bamfield Marine Sciences Centre (BMSC) on the west coast of Vancouver Island. Yet, even on Wizard Islet, at one of the most intensely studied sites on the entire BC coast, novel mapping techniques are opening a whole new toolbox of scientific possibilities.
At low tide, pools of seawater dot the rocks of Wizard Islet like puddles left on an uneven parking lot after a downpour. Myriad creatures inhabit each temporary tide pool. Clusters of green anemones cling to the rocky walls. A Dr. Seuss-ian collection of seaweed lives in the pools—maroon spaghetti, chocolate-colored steel wool, electric green tissue paper, and hot pink crusts. Barely noticeable fish the size of your thumb lie motionless, their camouflage betrayed only by an occasional dash after a morsel of food.
To understand life in these tide pools, scientists try to measure every dimension of these ephemeral habitats that come and go throughout the tide cycle. But even on tiny Wizard Islet, there are a staggering 934 tide pools. Measuring the details of every single pool was almost impossible—until drones came along.
In the summer of 2016, the Hakai Institute partnered with BMSC to add a new dimension to ecological data from Wizard Islet, data that stretches back decades. Using a small drone and a specialized GPS, Hakai and Bamfield researchers mapped in a few hours what used to take scientists untold days to measure. In just one low-level drone flight, they captured enough data to map the entire islet and all 934 tide pools in incredible detail.
Once they processed that data, scientists quantified every nook and dimple, down to a resolution of three centimeters. That’s like distinguishing between blades of grass on a football field from a photo taken atop a 23-story building.
Hakai scientists use software to precisely differentiate tide pools using images taken from a drone. Map by Keith Holmes
This new mapping technique is going to save scientists a lot of valuable time in the field. Sara Smith, now a PhD candidate at the University of Calgary, researched the fish living in tide pools on Wizard Islet in 2013. Back then, they only had enough time during one low tide cycle to sample fish in a few of the islet’s pools.
“These new maps give an insight into what this islet looks like without even traveling to the site. If we had these maps during my study, it would have allowed us to tag and sample far more fish during the limited time window at low tides when research could be done,” says Smith.
Wizard Islet is just one of many sites on the BC coast that are being mapped with drones. We’re just scratching the surface when it comes to the mysteries these maps can help unlock in every crack, crevice, and cranny on the coast.
Time is of the essence when scientists conduct research that can only happen at low tide. But with drones aiding their efforts, they have more precious minutes to carry out their studies. Until the tide comes in and the site is under the sea once again.
Acknowledgements
This work would not have been possible without the planning and coordination by Iain McKechnie. This project was part of broader mapping efforts in Barkley Sound conducted under Huu-ay-aht heritage investigation permit 2016-11 with the logistical support of the Bamfield Marine Sciences Centre and the Huu-ay-aht government. We additionally thank Bamfield Marine Sciences Centre staff Sean Rogers, Eric Clelland, Shirley Paulka, and John Richards, and Brad Anholt, as well as Huu-ay-aht First Nation members Rita Johnson and Stella Peters. Mapping was conducted by Hakai staff Will McInnes and Keith Holmes.