During our class’s recent trip to Brady’s Beach near the Bamfield Marine Sciences Centre on Vancouver Island, I became particularly enamoured with a little beastie common to the shorelines of British Columbia: the ochre sea star (or, Pisaster ochraceus if you’re feeling fancy). Almost a third of all the photos I took during the trip were of these five-limbed, brownish-orange and earthy-purple sea stars. The mushy-looking little guys are fairly unassuming at first glance – they pretty much just hang around, sitting on rocks, munching on mussels, and getting eaten by seagulls.
#1 – They live in tough neighbourhoods
Despite appearances, ochre sea stars are actually pretty tough dudes. For one thing, they are adapted to live in the intertidal zone (basically the area between where the waterline is during low tide and high tide). That may sound nice and pleasant, but it pretty much means they spend half their time underneath British Columbia’s not-so-warm water, and the other half getting pummelled with crashing waves. Every. Single. Day. Can you imagine what it would be like if you had to spend half your life getting punched in the face by Poseidon?
#2 – They have super powers
The ochre sea star is a freak with super-powered self defences. Kinda. The ochre sea star has the ability to regrow lost limbs in a pinch, so losing an arm or two doesn’t really matter all that much. While that may be pretty par for the course if you’re a sea star, from a human perspective it’s pretty unusual. For us, a normal response to getting mugged usually isn’t to yank your own arm off and hand it over. Nbd. But if you happen to be a sea star, a chopped off arm is no big deal because YOU CAN JUST GROW ANOTHER ONE. Some species of sea star can even reproduce this way, check it out here.
#3 – Everything falls apart if they skip town
Another cool thing about the ochre sea star is the fact that despite being smallish, slowish hunks of star-shaped tissue, they more or less run the show in the intertidal zone. That’s because they are what’s known as a key-stone species: an organism upon which a particular ecosystem depends. Sea stars eat animals such as mussels and barnacles, and even removing a few sea stars from the local ecosystem can allow the mussel population to grow out of control, displacing their neighbours (chitons, limpets, and hyrdoids, to name a few) lowering biodiversity, and throwing off the whole intertidal ecosystem. The humble sea star is basically the most important dude in the intertidal: nobody knows what do if he’s not around, and if he’s gone the whole town goes to shit.
So the next time you come across a sea star on the beach, give the little guy some respect.
For some more cool info on sea stars, check out this video: