Photographer Susan Middleton captures extraordinary world of marine invertebrates in all their colourful, diverse, and prickly glory

Middleton has been taking portraits of rare plants and animals for 30 years

Pink Brittle Starfish (Susan Middleton)

When Susan Middleton packed up her latest project, in July last year, she was bereft. And so the photographer, who had spent the previous seven years capturing the extraordinary world of marine invertebrates, turned to her diary for solace.

"I miss the animals," she wrote. "I miss watching them, the sound of water, the calmness, the chance to eavesdrop on their world. They inspire me, amaze me, surprise me – I can almost experience the distinction between me and them dissolving. Immersed and enraptured."

While squiggly underwater oddities might not sound like your average coffee-book subject, Middleton captures them in all their colourful, diverse, squishy and prickly glory.

The photographer, who lives in San Francisco, has been taking portraits of rare plants and animals for the past 30 years, and for this project, she travelled the Pacific Ocean with scientists doing field work.

The creatures were captured by marine biologists and divers, while Middleton set up a studio in the wet lab of the ship and modified aquariums to accommodate her subjects, building trays with glass bottoms. By then using white or black backgrounds, she was able to visually isolate them, and, after she took their mugshots, they would be reunited with the sea.

"As time has gone on, I have gravitated to the lesser-known, less conspicuous inhabitants of terrestrial and marine environments, which are no less important to how those eco-systems function than the larger, more well-known creatures," she says. "In a sense I am focusing on the 'underdogs' here. I think they could use some PR assistance."

'Spineless', by Susan Middleton, is published by Abrams & Chronicle Books, priced £30