A Season of Tiny Claws

It’s an overcast day in March, so there aren’t many people on the beach. This is my favourite time to swim. The tide is on its way out but this day won’t bring it very far. The water is relatively clear; no blooms, just a bit of sediment where the tide retreats from the rocks. Normally you don’t see Dungeness crabs close to shore unless you find a piece of their molt or they’ve been brought up by fishermen, so I’m pleasantly surprised when I see something move near my feet—until he tries to pinch me. We do a dance, if you can call it that—I try to get away, he chases me. I leave him in the water because I’m aware those claws have enough muscle power to take off a toe and I sit on the beach, watching him from the shore. He retreats back to deeper water. One day I’ll walk on this beach with my friend Vicky, pick up a carapace from the sand, hold it up so the light shines through it and she’ll tell me when she looks at it she sees the face of a deer. Vicky is a natural science and botanical illustrator. She sees magic everywhere and can translate it with expert precision. The first time I met her she gave me a magnifying glass. I've been looking at the world differently ever since.

Four months later I’m hauling up a light trap from the edge of a dock. It's exceptionally windy and the sun is blazing hot already at 9am. Iryana is next to me; we’re both helping trap and collect data about Dungeness megalopae this summer so we can better understand their life cycles. We talk about how much we love diving, how good it is that we’re fond of the sea since the waves are trying to pitch us off the dock. We count the megalopae. Dungeness crabs have 5 life stages they move through before they begin to crawl. Megalopae are planktonic, fragile; they have two outsized compound eyes and they are frequently eaten by schools of fish. We see a lot of those around the docks now, I think they see just as much value in the light traps as we do.

The megalopae are about the size of the tip of my pinkie finger, translucent for the most part with a dark spot of pigment in the centre. This will become their exoskeleton when they begin to molt. As the summer drags on there are fewer and fewer megalopae, more instars—these are the juvenile crabs at their next life stage. The larger ones fight each other in the tray while we try to count them. After this stage they’ll be too big for the traps. Juvenile Dungeness crabs leave behind the water column and their former planktonic lifestyle to settle onto the substrate. Preferably they do this somewhere like a bed of eelgrass where they’ll be protected and find adequate nutrients while they molt again and again and again—each time growing larger until they reach sexual maturity and their molting slows down. Once they’re sexually mature, male Dungeness crabs go searching for pre-molt females to mate with. Before they mate, they embrace. 

One day in June I am kayaking at Cates park. I spend a lot of my summer on the North Shore, swimming with moon jellyfish, hiking, chatting with fishermen on the docks about their catch. Not everyone is invested in sustainability, nor do they all see crabs as sentient and important. Their ecological role is lost on many. It’s illegal to harvest females and the small ones are insubstantial and commercially useless so they pick them up by the legs and chuck them back in the ocean—startling for the crabs, but they’ll be okay. Crabs are tough; they can regenerate their limbs and they’re hardy intertidal predators. They help control fish populations, recycle nutrients and provide nourishment to shore birds and sea mammals. Part of our focus with the light traps is predicting population numbers so we can ensure longevity of Dungeness crabs, not just for their economic value but for their ecological value as well. 

On this day I mainly wanted to spend time on the water for the sake of itself and to take pictures of kelp, but on my way back in I spotted what looked like two Dungeness crabs fused together, one quite a lot bigger than the other. Naturally (and irrespective of their privacy), I took some photos and then left them alone. When male Dungeness crabs find their premolt female, they hold onto her for around a week until she’s ready to molt. When she molts he transfers his sperm into her spermatheca where she’ll store it until the time comes. 

A man on the shore was hauling in an empty trap, discouraged. He saw me looking down and asked if I’d seen any crabs. I told him I hadn’t. 

Crabs, like all arthropods, are vulnerable after they molt, so the male will continue embracing her for several days to protect her from predators. Then he moves on, she fertilizes and broods her eggs, and then a few months later they’ll float along the water column, swimming up at night to feed and getting drawn in by a warm light that leads them into a bucket that Iryana and I will lift out of the water when the sun comes up.