How Blue Planet II filmed the stingray vs spider crab battle

Sequence director Yoland Bosiger reveals all…

“We’d heard about this massive aggregation of giant spider crabs — hundreds and thousands of them — which come out of the deep sea in the winter months just off the coast of Victoria in Australia. They come into the shallow waters to moult their hard shell and grow a bigger one.

“When they do that they become extremely vulnerable to predators because it takes a couple of days for that new shell to harden. It’s thought they come together like this to allow greater protection from predators.

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“When we first dropped down on them, it just looked like an incredibly dense patch of sea grass, but in fact it was this great writhing, undulating mass of spider crabs, ten deep in places. An incredible spectacle.

“We were sitting down there and they weren’t worried by us at all — they’d walk right over the top of us. While I’m not afraid of spiders, they do have these big long spidery arms, so it took a while to get used to that.

“Once they’ve shed their skeleton, they can’t really move their legs and are just sitting ducks for these huge stingray, which were like spaceships swooping down over the vulnerable crabs. They did try to fight back, but it was very much a one-sided battle.”