GS3 – Environment
Context
Sudden jellyfish blooms have been observed in Kerala’s Cochin backwaters, raising ecological and economic concerns.
What is a Jellyfish Bloom?
- A dense aggregation of jellyfish triggered by environmental changes, typically during April–May and October–December across Indian coasts.
Species Reported:
- Acromitus flagellatus, Blackfordia virginica, Pleurobrachia sp., Pelagia noctiluca.
Causes:
- Nutrient Overload: Eutrophication from agricultural runoff increases phytoplankton, jellyfish prey.
- Environmental Degradation: Warming waters and pollution deplete oxygen, favouring jellyfish over fish.
- Coastal Dynamics: Tides, winds, and currents push jellyfish toward shores, increasing bloom density.
Kerala’s Unique Bloom Pattern:
- Extended Bloom Periods compared to other coasts.
- Persistent Salinity: Backwaters remain saline during dry months, supporting jellyfish survival.
- Low River Discharge: Delays flushing of jellyfish out to sea.
- Tidal Mixing: Maintains warm conditions suitable for bloom persistence.
Impacts:
- Fisheries Affected: Jellyfish block fishing nets, damage gear, and reduce fish catch.
- Tourism Losses: Jellyfish stings deter beach tourism, affecting local economies.
- Ecosystem Imbalance: Jellyfish dominate degraded environments, lowering biodiversity.
- Biogeochemical Shifts: Blooms speed up organic matter decomposition and disrupt nutrient cycles.
About Jellyfish:
- Belong to phylum Cnidaria, soft-bodied, gelatinous, and unable to resist strong ocean currents.
- Found in marine and brackish ecosystems across climate zones.
- Highly responsive to variations in temperature, salinity, and nutrient concentration.
Positive Ecological Roles:
- Zooplankton Regulation: Feed on small organisms, maintaining ecological balance.
- Nutrient Cycling: Decaying jellyfish contribute to coastal nutrient flows.
- Biochemical Applications: Being researched for use in nutraceuticals and pharmaceuticals.