Polychaete Worms

About Polychaete Worms

• Polychaete worms are segmented worms, or annelids.
• They are among the most diverse groups of marine invertebrates on Earth.
• The name Polychaeta means “having much hair”.
• Bristles are present on their fleshy, leg-like body parts thus, these worms are also called bristle worms.
• Habitat: They are found in almost all marine habitats, including estuaries, mangroves, sandy shores, coral reefs, seagrass beds, continental shelves and deeper waters.
  • A small number of species can also live in low-salinity and inland waters.
• Distribution: India has a large diversity of polychaete worms because of its long coastline and varied marine habitats.
  • There are about 8500 species worldwide which includes 400 species reported from Indian waters.
• Characterstics:
  • They have parapodia (small leg-like structures) for crawling, swimming and burrowing.
  • Each segment has a pair of parapodia with chaetae (bristles).
  • Their bodies consist of circular layer of muscle around a coelom (fluid-filled space).
  • Many have tentacles for feeding or feather-like branchial radioles for feeding and breathing.
  • They range in size from a few millimetres to more than a metre.
  • They may be of dull brown, yellow or orange-red in colour.
• Ecological role: They play several important roles in marine ecosystems.
  • They may act as deposit feeders, filter feeders, grazers or predators.
  • As detritivores, they help break down organic matter, transport oxygen and redistribute nutrients.
  • They are also an important food source for other marine organisms.
  • Their sensitivity to environmental changes makes them useful bioindicators of ecological health.
• Threats: Their habita can be affected by sediment changes, tidal exposure, dredging and other human disturbances.
  • Although some species can survive polluted and low-oxygen sediments.
  • Wild harvesting is another concern because polychaete worms are widely used as live feed in shrimp hatcheries due to their rich polyunsaturated fatty acid (PUFA) content.