B.C's pink sea urchins are on the move to shallower waters thanks to climate change

Photo: The Canadian Press

Deepsea fragile pink sea urchin aggregating to feed on decaying seaweed at the Endeavour site during a 2016 expedition, is seen in this image provided February 7, 2023. Pink urchins like these are expanding their territory into shallower B.C. water. Researchers say the movement is a sign of how fast climate change is impacting life in the water. THE CANADIAN PRESS/HO-Ocean Networks Canada/WHOI 

Pink sea urchins off the coast of Vancouver Island are expanding into shallower waters, in what researchers say is an indication of how rapidly climate change is affecting ocean life.

Researchers at Memorial University, Ocean Networks Canada and the University of Victoria found the urchins were moving into shallower water at an average rate of 3.5 metres per year as climate change and warming water reduce oxygen levels and food sources at lower depths.

The study's co-author Rylan Command says the movement of the pink urchins could, over time, lead to them replacing other species, like red sea urchin harvested in fisheries.

Researchers looked at 14 years of data including before, during and after the marine heat wave that persisted in the Pacific Ocean between 2013 to 2016 and became known as "The Blob."

Study co-author Fabio De Leo, who's with Oceans Network Canada, says warming from The Blob destroyed much of the kelp the urchins eat causing their populations to drop off dramatically.

The researchers say the warmer-than-normal surface temperatures also disrupted the ocean process known as "upwelling" when nutrient-rich water from lower depths cycles up to the surface, potentially affecting where the urchins find food.