Blue Whales and the Circle of Poo
In the Southern Ocean, surrounding Antarctica, blue whales were nearly wiped out by industrial whaling from the 1920s to 1940s. But now, with whaling curtailed, the whales are surging back: their population growing by 7.3 percent per year. By 2066, blue whale numbers could be back to historic levels. For conservationists, this last-minute rescue of the largest animals on Earth is a good news story. For others, the blue whale’s return is a daunting prospect. As conventional thinking suggests, the resurgence of these massive creatures—with their equally massive appetites—is creating an ever-greater competition for the commercial krill fishery.
These worries are not entirely unfounded. In the Southern Ocean, shrimp-like krill sit near the base of the food web. Estimates place the total krill biomass in the sea at 379 million tonnes. Each year, commercial trawlers pull in up to 5.6 million tonnes, and during peak feeding season a blue whale can eat nearly four tonnes of krill a day. With a pre-whaling population of 239,000 in the Southern Ocean, blue whales will soon be consuming a decent chunk of the total krill. That would leave the commercial trawl fleet—mostly from Norway, South Korea, and China—with fewer krill to use in fish meal for aquaculture and aquarium feeds, in vitamins or pharmaceuticals, or as bait for sport fishing.
Hakai Magazine explores science, society, and the environment from a coastal perspective. The magazine is part of the Tula Foundation and Hakai Institute family. While proudly independent, Hakai Magazine shares the same philosophies as the Tula Foundation, celebrating exploration, discovery, and science. The name Hakai is inspired by the Hakai Lúxvbálís Conservancy, the largest protected marine area on the west coast of Canada, located about 400 kilometers north of Vancouver.