Just call me “Kimfishley” because I’m going off brand!
I recently went looking for freshwater fish with the wonderful Stella McQueen. She runs an awesome Facebook page about New Zealand’s native fish where she educates and advocates for these quirky and amazing creatures. Not many New Zealanders know we have freshwater fish or that 74% of them are threatened or at risk of extinction.
Our trip took us to Korokoro Stream, which runs through an industrial area in Lower Hutt (just out of Wellington). It meanders through a weed-infested valley, dodging old rubbish and piles of brick from the mill that was once there.
Pair this with the patches of filamentous green algae scattered through the river and it’s easy to guess why I was sceptical there would be any fish living here. Especially after reading about how sensitive they are to pollution and changes in water quality.
Korokoro Stream surrounded by weeds, weeds, and more weeds (seriously, invasive plants like Old Man’s Beard can just block out native species and take over!)
But Stella was confident there would be something to see and had even heard a rumour the stream was full of bluegill bullies, which she had never seen in the wild before. So we set about our adventure, scuttling down the bank with a net and a bucket to get started.
New Zealand has 66 fresh water fish species, but around half of them are nocturnal and very secretive. You’re unlikely to see them while swimming in your local river or stream over the summer. No, finding these elusive creatures takes a special technique…
Stella started by showing me the easiest way to look for fish, using a hand net. She put her net downstream of something called a “riffle” (where the water flows more quickly) and turned over the rocks. The idea is to catch anything that becomes dislodged in the net as it heads down-stream.
Stella with her hand net on a “riffle” turning over stones to find elusive native fish.
Using a hand-net is an easy way for people to get started looking for fish, but Stella was keen to find a bluegill bully. So she called in the cavalry – a large net (known as a stop-net) with two poles and a chain along the bottom to anchor it in the stream.
Her friend Duncan held it in place downstream, while Stella twisted her feet through the stones to dislodge any fish that were hiding. I joked that it could take off as a cool, new summer dance craze (though all joking aside, I fully intend to bust it out the next time I find myself on the d-floor).
Stella and Duncan demonstrate what we have called “riffling” for fish by turning over stones and holding a net downstream to catch any dislodged fish.
After our first try “riffling” (which is the name we gave it after we realised there isn’t a specific name for this fishing technique), we caught our first fish for the day. Stella leapt with joy as she realised it was a bluegill bully, a species she had never seen in the wild!
Named after the bright blue membrane that covers their gills, they are the smallest of New Zealand’s “bullies” and only grow to around 60 millimetres long.
Although not a lot is known about the bluegill bully’s life-cycle, we know that they become fiercely territorial during breeding season. Males decide on a “spawning rock” where females are likely to lay eggs for them to fertilise. They defend it viciously until the eggs hatch and the tiny bully larvae wash out to sea. After around six months, they swim back to fresh water where they live under rocks near riffles and rapids in their chosen stream.
A bluegill bully showing off its distinctive blue gull
As we moved upstream, we kept getting more and more fish. About 7 out of every 10 times we lifted the net, there was one wriggling around.
We quickly started catching redfin bullies which, as you will probably guess from their name, have beautiful red fins. The ones we caught were a more reddy-brown colour because they were females, which have duller colours. Interestingly, the vibrancy of their colouring depends on how dark or light their surroundings are.
Redfin bullies that live in darker streams or environments have a more vibrant red colour to them, while fish living in shallow, clear streams with lots of light (like the one we were fishing in) are a lighter, red-brown.
This male redfin bully was one of the bigger fish we caught.
After catching the fish, we put them in a covered bucket to make sure they weren’t too stressed, making sure to change the water part-way through so the fish had enough oxygen and adding branches to give them something to hide under.
We caught around 27 fish – plus a juvenile eel (which are known as elvers). Stella guessed it had only been in the stream for a few months. Before that, it had swum all the way from Tonga where it was spawned. What amazing life-cycles our native fish have!
A bucket with just some of the fish we caught.
At the end of our adventure, we released the fish. I crouched in front of the bucket with Stella’s underwater camera to film their liberation (watch a video of them in the bucket here). However, I didn’t quite think this through as once we released the fish, they swam upstream to the nearest large object under which they could take cover.
I quickly found myself surrounded by 20 little fish, swimming vigorously around my knees, ankles, and hands to find a safe place to hide. I carefully removed myself from the water and left them to find some fish cover that was less… temporary.
Releasing the fish back into the stream (and being temporary fish accommodation).
It was an incredible day and I can’t thank Stella enough for taking me to see my first freshwater fish in the wild (seriously, follow her Facebook page and buy her book about freshwater fish).
Sadly, more of our freshwater fish are under threat than ever before, because the way we use land has changed. Over the past 25 years, there has been more intensification of land for agriculture and urbanisation is increasing, which means the quality of our streams is being degraded, polluted, and in some places drained or diverted.