There are a number of factors contributing to the increase
of jellyfish blooms, most of which are linked to global warming. Jellyfish are thriving due to warmer
and saltier waters as well as an increase in plankton growth. In addition, overfishing has created a
niche for jellyfish to exploit. In
years before predators were consuming much more of the ocean’s nutrients. Now however, there is less competition
leaving more for jellyfish. This
is also the case with agricultural runoff, where jellyfish are able to
capitalize on the organisms feeding on the bacteria.
The current trend in climate change shows that the ice cover
is melting much later in the spring, spawning more rapid and increased amounts
of plankton growth. There are
various theories based on this evidence, but perhaps the strongest supports the
idea that increased sunlight is favorable for the plankton. This is especially true in colder
regions such as the Bearing Sea, where scientists and fisherman alike have
noticed drastic increases in jellyfish blooms. But despite recent awareness, population control will only
be a reality once the global climate patterns stabilize.
For most, summer draughts mean hot days and dry
gardens. For jellyfish, however,
it means saltier waters. As rain
becomes less frequent there is less fresh water entering the ocean. Although it’s not the case with all
jellyfish, most will benefit from a higher salt content. This also relates to other predators
and fish species, which are less tolerant of the salt increase and will often
move from the coast into deeper, less salty waters.
As the ocean gets warmer and the water level rises, the jellyfish
survival rate also goes up. It
creates the right conditions for jellyfish blooms to prosper, which results in
a longer span of migration. Now
there are jellyfish species that are being labeled invasive. Beachgoers have to swim with a new
element of caution, unable to know which new species has moved in, and which
has left.