Nick Hawkins / American lobster (Homarus americana) in eelgrass (Zostera marina). Nova Scotia, Canada. July

Juergen Freund / Saltwater crocodile (Crocodylus porosus) swimming at water surface, split-level, New Guinea, Indo-pacific

Gary Bell/ Oceanwide / Eelgrass (Zostera tasmanica), Hopkins Island, South Australia, Australia

Nick Hawkins / Common eel grass (Zostera marina) in Kejimkujik Seaside National Park, Nova Scotia, Canada. July.

Nick Hawkins / An Atlantic polluck (Pollachius pollachius) swimming over a patch of eelgrass (Zostera marina). Nova Scotia, Canada. September

SCOTLAND: The Big Picture / Seagrass (Zostera marina) bed, Scotland, UK, May.

Alex Mustard / Spiny seahorse (Hippocampus guttulatus) female in a meadow of seagrass. (Zostera marina) Studland Bay, Dorset, England, UK. English Channel.

David Fleetham / Eel grass (Zostera) off the Wakatobi Resort, Indonesia.

Nick Hawkins / Atlantic herring (Clupea harengus) schoal of juveniles in eel grass beds, Nova Scotia, Canada, July.

Sue Daly / Tracking shot over a patch of Eel grass (Zostera marina), Sark, British Channel Islands, UK, June.

Alex Mustard / Seagrass meadow / Common eelgrass / Seawrack (Zostera marina) next to Swanage Pier, Swanage, Dorset, UK August

Doug Perrine / Group of California sea otters (Enhydra lutris nereis) resting in a raft at the edge of a bed of Eel grass (Zostera) Morro Bay, California, USA, June.