Donning full scuba gear and tank—with a clipboard, fins, and underwater camera somehow all wedged, clipped, or balanced around my body—I sank into the inky, inscrutable water. Earthly burden lifted, I joined the weightless and serene world of the coral reef at dawn.

Crossing the reef crest, with the sun rising behind me, I dropped down the coral wall, still in blackness save for a school of bioluminescent flashlight fish, whose symbiotic bacteria emitted an incongruous glow from specialised sacs beneath their eyes. My presence scared off these skittish biological lanterns, leaving the reef uncharacteristically quiet as I descended into the dark. My goal at this unsociable hour was to become one of the privileged few who have ever witnessed the birth of a pygmy seahorse. Enigmatic, charismatic, and poorly known, these miniature fish had been reluctant to give up their secrets, until now.”

The above expert from my book, The World Beneath: The Life and Times of Unknown Sea Creatures and Coral Reefs, describes a day from my PhD fieldwork as I learned about the lives of little-known pygmy seahorses.  I have long-been fascinated by the natural world, so the career I have forged is a dream come true. Combining natural history observation, with underwater photography and the science of marine biology allows me to really see coral reefs and their inhabitants in a different light.

I started in underwater photography as a way of recording detail in the tiny nudibranchs I would find, but had no way to identify – the scrappy little sketches on my slate just didn’t cut it. Photography later became invaluable in my PhD research on the biology and conservation of pygmy seahorses. Without physically accosting a pygmy, the only way to identify its gender is by taking a very close up picture underneath its trunk.

The biggest thrill in my line of work is descending on a dive, with no idea what I might find. This might be a behaviour I have never before seen, a species I have never encountered or even something entirely new to science…in the ocean it’s impossible to know what you might come across.  It certainly helps to have a good knowledge of the usual suspects on a reef, those species that you would expect to encounter, so when you see something different you will recognise it.

Each time I dive a new location, I am sure to have investigated all the special or indigenous animals that reside there, to make the most of my limited time in the water. In the Galapagos recently, I was a huge annoyance to the local sealions as I photographed the stunning endemic pikeblenny. The three-inch-long male fish popped out of the sand and opened wide their stunning dorsal fins. Meanwhile, the sealions were desperate to known why I wasn’t paying them any attention. In fact, the same situation occurred in the Sea of Cortez, whilst I was shooting indigenous triplefin fishes. The sealions got so irritated that one put my whole head in its mouth in a ‘play with me’ kind of way. It was very delicate; I only had the faintest scratch on my forehead from a canine!

I have always favoured the smaller, overlooked underdogs in the natural world. Sadly, these are the species that have and will go extinct first. In conservation, big charismatic animals like tigers and pandas take most of the limelight, but smaller animals also suffer wide-ranging threats. This situation is the same both above and below the waves, although we start from a position of extreme ignorance when it comes to the biology of most marine animals.

Parasites are certainly one group that are overlooked, and have the dubious honour of being the only ones that biologists aim to eradicate. We humans suffer from several hundred parasites, such as malaria, tapeworms and lice, but they are equally prevalent in the oceans. Having become fascinated by the isopod parasites I saw clinging to the flanks of damselfishes, I spent the next few years hunting for more. The majority I have come across appear to be undescribed, including one that lives inside the nostrils of crocodilefish and another that is ghostly white to camouflage itself under the chin of fusiliers. As much as they might sound repulsive they are just another component of the tree of life and vital for its healthy functioning.