Ragworm

Ragworm is a common name for several large marine polychaete worms in the family Nereididae. In Europe and North America, species such as Hediste diversicolor (formerly Nereis diversicolor) and Hediste virens (formerly Nereis virens) are frequently referred to as ragworms. They occupy shallow coastal habitats including estuaries, mudflats, and sandy or silty sediments.

Ragworms are elongated, segmented worms with numerous parapodia (paired outgrowths) along most segments. Each parapodium bears bristle-like chaetae. The body coloration varies by species and can range from reddish or brownish to greenish hues. Individuals can reach several centimeters to well over 10 to 20 centimeters in length, depending on species and conditions.

Ecologically, ragworms are important benthic invertebrates. They excavate burrows that aerate sediment and influence sediment structure. Their feeding habits are omnivorous and carnivorous, including detritus and small invertebrates. They serve as a significant prey item for shorebirds, fish, and other predators and thus form an important link in coastal food webs.

Reproduction in ragworms is typically sexual with external fertilization. Eggs and sperm are released into the water column, and early development proceeds through free-swimming trochophore larval stages before settling as juveniles. Some species may exhibit seasonal spawning patterns tied to environmental cues.

Humans interact with ragworms mainly as valuable live fishing bait and as indicators of estuarine and coastal ecosystem health. They are also studied for their roles in sediment turnover and ecotoxicology due to their sensitivity to environmental changes.