For this installment of Video of the Week, we had the chance to sit down with Jack Kos, and ask him a few questions about his film that documents the introduction of the brown trout in New Zealand. If you do not know too much about the history of the New Zealand brown trout, be sure to tune into this film to learn about this interesting story.

Fly Lords: What prompted you to start digging so deep into the history of the brown trout in New Zealand?
Jack: A combination of curiosity and opportunity. I was going into an Honours year in History at Canterbury University, and had the chance to write my thesis on anything I wanted. Given as I’d probably skipped a hundred lectures in the prior few years to go fishing it seemed only fitting to bring the trout to school. I started researching the introduction of brown trout to Canterbury, and became entirely lost in the story. Through an incredible public newspaper archive I was able to follow the introductions day by day, sometimes even hour by hour and I came to realise how significant of an event it was to transport these fish thousands of miles, rear and then distribute them. From then on it was only natural to follow the story to its completion and I was lucky enough to get funding to do a PhD at Otago University on the introduction of brown trout to New Zealand.
Fly Lords: There are obviously stocking programs all over the world for brown trout, what has caused New Zealand to stand out and given these fish the opportunity to grow to the massive size that they are?
Jack: Honestly, you’d have to ask an freshwater ecologist to really get to the bottom of this one. From my understanding it’s a combination of water clarity (facilitating excellent visual feeding), relatively mild winters and water temperatures falling within the optimal growth size. This is then moderated by having relatively marginal habitats in terms of stability and insect numbers, which results in few, but large, trout. How I often explain it to friends is that in most instances rivers around the world seem to have a similar biomass of trout – it’s just that in blue ribbon waters in the US that might mean 1000 smaller fish a mile, whereas in New Zealand it’s more likely to be 100 larger fish per mile (or in some instances as low as 5 typically very large fish per mile).
Fly Lords: Is there still an active stocking program in New Zealand, or are these fish now self sufficient?
Jack: Well, both… The majority of New Zealand’s rivers aren’t regularly stocked and have self-sufficient populations of wild rainbow and brown trout, but there are a few exceptions to this rule. Some regions, such as Rotorua, stock fairly heavily and produce phenomenal fish – I guess it’s all just different management strategies. The postcard backcountry South Island brown trout, however, are more than likely wild and self-sustaining. In many instances they’re part of populations that could trace their origins back to those original brown trout brought to New Zealand in the late 1860s.
Fly Lords: Because all of these fish have been stocked, is there a risk of coming across a river that still has yet to see a trout?
Jack: Stocking took a few different forms. What we first think of in the case of New Zealand is British colonists physically placing trout fry into rivers and lakes, and a huge number of waterways were stocked this way. But the trout were themselves colonists, spreading throughout those river systems into tributaries and even running out sea and along the coastline and up rivers that probably hadn’t seen a human being at that time . Through this combination of human assistance and natural spread brown trout became hugely wide spread throughout the country. That said, there’s still a risk of coming across a river without trout, usually because a natural feature like a waterfall prevents passage.¬† But truthfully I don’t think that’s something we should think of as a “risk” at all. Trout predate heavily on native fish, so to have certain waterways that exist as a sort of native fish reserve is likely a very beneficial thing, even if it is a bit of a bugger for an angler that might have walked 10 miles to get there…
Fly Lords: What are the first steps in ensuring that New Zealand continues to be a world class fishery in the years to come?
Jack: For starters, watch and share this film! I think the biggest factor in protecting our fishery is simply to be aware of the threats, which are twofold in New Zealand. Lowland fisheries are subject to immense environmental pressure, with increasingly intensive agriculture both abstracting water from the rivers as well as pumping pollutants into them. So don’t buy the clean, green Tourism NZ marketing campaign – we need to starting getting our processes in order before we lose these fisheries for good. Contrastingly, backcountry fisheries are quite simply being overfished. International anglers are probably astounded by the seeming lack of angling pressure in New Zealand compared with their home waters, but they need to acknowledge how different of a fishery the New Zealand backcountry is. When floating a river with thousands of fish a mile almost regardless of how many drift boats go by each individual fish cannot be targeted by an angler (whether hooked or spooked), whereas in New Zealand because of the low numbers of often very visible fish each individual fish can be targeted by every angler to go by. So even if only one party goes through a day, the relative impact on the river is likely far greater. So I’d encourage visiting anglers to be judicious when deciding where to fish – don’t simply fish the same waters that you read about in the books, and certainly don’t fish them for multiple days in succession. New Zealand has some exceptional lake fishing also, which tends to get looked over. Explore widely, fish different spots, perhaps unknown spots, and you’ll probably be rewarded with the best fishing of the trip.
Be sure to follow Jack to keep up with what he is doing and also check out Side Channel Productions, who produced the film.
The video of the week is selected and written by FlyLords team member Conner Grimes.