Why are there salps?

Laurence P. Madin, Ph.D.
Woods Hole Oceanographic Institution

Wednesday, April 15, 1998
3:30 p.m.—Pacific Forum

Salps are pelagic tunicates that seem almost perfectly adapted to life in the oceanic water column. They possess unique and highly efficient modes of jet propulsion and filter-feeding that enable them to travel further and eat more than many other zooplankters of comparable size. Some species occur in dense seasonal populations in coastal waters or polar oceans; others appear to be sparsely distributed everywhere. Some species migrate up to 800 meters daily, while others never leave the epipelagic zone. All appear to have the same feeding mechanism and diet.

This talk summarizes what we know currently about the functional morphology, physiology, behavior, and ecological role of salps, reviewing recent research on feeding and energetics, diel migration, and reproduction. Among many unanswered questions to be discussed are: How did salps evolve? Why are some vertical migrators and others not? Why are there so many species? How do they navigate? What controls their reproductive cycle? What causes some species to form huge blooms? Where do they fit in planktonic food webs?

Next: Photoluminescence and fluorescence