The continuing adventures on Kawakawa Island - in which we make an exciting discovery
As you may have read in my previous posts Kawakawa Island - our lockdown nature restoration project and Journey to Kawakawa Island, our family has been spending a bit of time down the bottom of our gully, removing the thick carpet of tradescantia and planting kawakawa and other seedlings of species that naturally grow in the gully ecosystem.
Yesterday, when I was rescuing a mahoe from the suffocating tentacles of tradescantia, I asked my son to fetch a rock from the stream, to prop the little fellow up (the long-suffering plant had been growing horizontally under the wait of the ravaging succulent). My son, was grabbing a rock, when he uncovered a freshwater crayfish. He yelled out with such excitement that I raced over and indeed - they he was (everyone is a 'he' in this story), a fine-looking fellow indeed.
I remember seeing freshwater crayfish (Paranephrops planifrons) hanging out at the stream down the back of my cousins' farm in Tokomaru as a kid - but I have not seen one as an adult (then again, I don't spend a huge amount of time looking under rocks in streams!). My son, by contrast, has never seen a kōura in real life - though he knew immediately what it was. So we felt privileged to meet this little fellow, let alone in the small, ephemeral stream down our gully.
This discovery has only made us more motivated to make this a suitable place for kōura, through restorative planting (reducing sedimentation) and we see our neighbours upstream are fencing off the tributaries to the gully stream, so this can only help contribute to stream health. So here comes the important part of the story. We swear (and this is not one of those big fish stories!) that the fellow we saw was 7cms long. This would make him a grandaddy because this is how big the North Island species grows. And did you know (we didn't) it takes 3-4 years for a kōura to just reach 2 cms in length? Just this knowledge really reinforces how precious these little survivors are.
Anyway, keen to have photographic proof of his discovery of a monster cray, my son rushed back up to the house to get his phone to take a photo, but in the fading light of the afternoon (the sun sets even quicker when you are down a deep gully) he couldn't get a clear shot.
Mum went back this morning and searched the area for about half an hour when the little fellow pictured above scuttled out (to bring some gender balance, we will call her a girl). She was about 4.5 - 5cm long (I took my son's metal ruler) - and her front pincers were much less pronounced, so evidently another individual in this kōura whānau.
This stream pretty much dries up at the height of summer, just with some isolated muddy pools left here and there, so I wondered, how would kōura survive through a dry period. But apparently, while kōura generally shelter between stones on gravelly stream bottoms, in wetlands they can burrow well down to wait until water returns. I guess our little stream-dwellers also have such burrowing abilities to have survived this long in the gully stream. As kaitiaki of our stretch of stream, we will be doing our utmost to ensure that they continue to thrive here.
See also Subterranean adventures.