Salpidae

Salpidae is a family of pelagic tunicates within the order Salpida, class Thaliacea, subphylum Tunicata of the phylum Chordata. Members are free-swimming, gelatinous, barrel-shaped animals that can occur as solitary individuals or as chains of linked zooids produced by asexual budding. The body is enclosed by a tunic made of tunicin and has two openings: an oral siphon for drawing in seawater and an atrial siphon for exhaling it. Muscular contractions along transverse bands propel the animal by jet propulsion. Feeding occurs as seawater passes through a pharyngeal basket; a mucous net secreted by the endostyle traps phytoplankton and other tiny particles for digestion.

Life cycle in Salpidae is often complex, with alternation between generations. Asexual, chain-forming generations bud off new zooids from the leading end of the colony, while sexual generations release gametes to produce larvae that develop into new individuals. Some species also maintain solitary life stages. This combination allows rapid local population expansion under favorable conditions and contributes to their ubiquity in open-ocean environments.

Distribution and ecological role: Salps are found in oceans worldwide, from tropical to temperate regions, primarily in open, nutrient-rich waters. They can form dense blooms and contribute substantially to zooplankton biomass. Through filter feeding, they help regulate phytoplankton communities, and their fast-sinking fecal pellets and, when present as colonies, gelatinous bodies, contribute to the marine carbon cycle by transporting carbon to deeper waters. Salps are prey for a range of predators, including fish, sea birds, and marine mammals.