An introduction on Jellyfish blooms
Chennai’s coastal waters and harbor-waters have witnessed jellyfish blooms time and again. As early as in 2018, for instance, visitors gathered at the city’s port as a part of the Defence Exhibition were treated with an unexpected surprise – the sight of hundreds of orange blobs blanketing the ocean surface near the shore.
Jellyfish blooms are sudden upsurges in the jellyfish population within a short span of time, and humans are believed to have a major hand in their occurrences.
Swarms of jellyfish have been observed at numerous coastal regions of our country, such as Mumbai, Goa and Thiruvananthapuram, in addition to Chennai. Having no brains, lungs or intestines, and made up of about 95% water, these free-swimming marine creatures are slimy mysteries that are waiting to be unravelled completely.
Why do jellyfish blooms occur?
The reasons behind the booming jellyfish population are not clear, but are often associated with adverse impacts of human activities on marine ecosystems. Some marine experts think that their increasing numbers are related to rising pollution. When sewage, fertilizers, pesticides, etc. are drained into oceans (directly or indirectly), they increase the volume of nutrients present in them. These nutrients increase plankton that are fed on by jellyfish. Putting two and two together, jellyfish numbers are bound to increase with rising pollution levels of oceans. But pollution alone does not cap the list of reasons behind burgeoning jellies.
Sudden blooming of jellyfish may also be caused by the effects of climate change on ocean temperatures. Global warming has been heating oceans for decades now. Many marine species have already begun dwindling. Unfortunately, an often ignored threat adds on to the list of problems they are facing. Unlike many marine species, jellyfish can flourish in warmer waters with less oxygen. So, the warmer oceans become, the more jellyfish we get to see.
A rising jellyfish population undoubtedly means negative impacts on socio-economic activities. But a greater threat lies in the fact that these creatures feed on fish eggs and larvae, implying a bleak future and grim survival possibilities for most marine species.
According to Dr C Venkataraman, a scientist at the Zoological Survey of India, overfishing and trawling could also contribute to the exploding population of jellyfish. Overfishing reduces predatory fish that consume these gooey creatures. This creates a mismatch in enumerable food chains and food webs of marine ecosystems, threatening to snap the delicate thread that we have treaded on so far.
For some, jellyfish may be a source of fascination; for others, a source of disgust. In either case, it’s hard to deny that they represent our fundamental errors of today. These jellies are mirroring the adverse environmental consequences that our actions have reaped. It’s up to us now to take their presence as a cue with foresight and reform our actions before it’s too late.