SCOTLAND: The Big Picture / Maiden's salp (Thetys vagina) , west coast of Scotland, UK, July.

Juergen Freund / Salp (Salpidae) colony with diver in the background, North Sulawesi, Indonesia.

Norbert Wu / Scuba diver and salp chain showing asexual reproduction of salps, southern California

David Fleetham / Pelagic tunicate or salp (Salpa aspera) Hawaii.

David Fleetham / Pelagic tunicate / salp (Salpa aspera), at night, Hawaii.

Doug Perrine / Rover fish (Emmelichthyidae) juvenile sheltering inside a colonial salp at night in surface waters of deep ocean off Kailua Kona, Hawaii, USA.

Doug Perrine / Parasitoid deepsea hyperiid amphipod (Phronima sp.) parasite riding inside the shell of its host salp, Kona, Hawaii. USA. Central Pacific Ocean.

SCOTLAND: The Big Picture / Amphipods (Amphipoda) living on a salp (Salpidae), Scotland, UK, July.

Solvin Zankl / Pram bug (Phronima) female with young in nest made from salp body, Atlantic Ocean off Cape Verde. Captive. Highly commended in the GDT European Wildlife Photographer of the Year 2017.

Albert Lleal / Salp (Thalia democratica), oozoid in solitary phase, Mediterranean Sea, Barcelona, Spain

Tim Laman / Salp (Salpidae) floating on the currents of Cebu island, Philippines.

Richard Herrmann / Salp (Salpidae), San Diego, California