"I was filming in the Coral Sea when a huge shark rocketed up from the deep and came straight for me..."

How did you get into photography?

I tried being a normal person with a respectable career, but that got old really quickly. I started dabbling with underwater photography and within a few years I had traded business suits for wetsuits.

• "I was simply terrified. I felt the whoosh of the current – then it was gone, leaving only a cloud of scales and blood swirling in my flashlight beam"

What shot is most meaningful to you?

In 2000, I met a juvenile sperm whale who used me as a chew toy. We then became best friends and spent three hours together. One of the resulting photos, a shot into its open mouth, won a major contest in Japan.

It also made the headlines, because the whale had a longline and hook embedded in its mouth.

Many of your shots are of whales defecating. Which poo stands out?

So many... If I have to pick one, then the great defecation of 2014. Dozens of sperm whales were intertwined in a cluster, and many let go' as they unravelled. I had to swim for 150m through a fog of watery poo.

Why is whale poo good for the planet?

What's been your closest shave?

I was filming in the Coral Sea when a huge silvertip shark rocketed up from the deep and came straight for me. It dug into the sand just centimetres to my left, shoving my legs aside. Then it was to my right, its body vertical, tail flailing. After what felt like hours - but was probably 15 seconds - it lost interest and streaked away. The footage was deemed too scary for the final cut.

• Watch terrifying, close up footage of a great white shark stalking a lone, vulnerable spear fisherman deep in the ocean
• How deadly are sharks to humans? 

How many cameras have you lost at sea?

Four. One drowned by a breaching whale, two whose seals failed, and a customised piece of kit that fell off the back of a boat.

By the time I noticed, the camera, housing and all my photos were at the bottom of the sea. Therapy might help me to recover more repressed memories.

Getting a shot of what species will make you die happy?

The platypus. It is so unique, so awkward in appearance, so intriguing. From the marine world, it'd have to be the giant squid. But one dragged a friend 40m underwater, so maybe I'll stick to the platypus...

Tony Wu is a marine photographer from Japan.

• “A colossal crab the size of a car tyre was pushing against my door”
• “Seriously underestimated.” Shark experts looked into the eyes of this deep-sea giant and were stunned by what they saw