Taken from the Pacific Institute for Climate Solutions website
Reports of jellyfish populations booming around the world have become commonplace over the last few years. Now, a study from the University of British Columbia has quantified these reports for coastal waters. In about 62 per cent of the ocean’s major ecological regions, it seems jellyfish are blooming in greater numbers, blooming earlier, or staying later in the year than normal. The paper doesn’t declare any one factor as the cause, but lists several contributing problems including lower oxygen levels, overfishing, lower salinity and global warming. Waters warming in regions further and further north are supporting a poleward shift in the range of jellyfish species and introducing them to new ecosystems. Some ecosystems previously dominated by fish have already shifted to being dominated by jellyfish.
Jellyfish may not seem overly harmful, but blooms have caused issues such as capsizing ships, or more seriously, potentially causing a nuclear incident. Sweden shut down a reactor last year after jellyfish clogged the intake of cooling seawater at a nuclear plant. On Jellywatch.org users can track blooms and help create data, as well as download an app for iPhone and Android. Last weekend, for example, one user reported seeing a ‘fried egg’ jellyfish near Comox on Vancouver Island. Off the BC coast, populations of jellyfish are expected to remain stable coming years, but along the west coast of the US they are expected to increase, and some areas off the coasts of Antarctica, Alaska and Japan can expect significant increases. The study’s authors say that with a phenomenon this widespread, adaptation to greater jellyfish populations will become a requirement, not an option.