Salpa fusiformis, sometimes known as the common salp, is the most widespread species of salp. They have a cosmopolitan distribution, and can be found at depths of 0to. They exhibit diel vertical migration, moving closer to the surface at night.[1] [2] They can occur in very dense swarms, as solitary zooids or as colonies. Solitary zooids usually measure 22to in length. They are barrel-shaped and elongated, with a rounded front and a flat rear. Aggregate zooids are 7to in length individually (excluding projections). They are usually barrel or spindle-shaped.[3]
The incursion of a large number of Salpa fusiformis into the North Sea in 1920 led to a failure of the Scottish herring fishery.[4]