What if we can have the best of both worlds – brilliant trout fishing in the mountains of the Western Cape AND new (yet ancient) fisheries for large indigenous species that readily take a fly? If game-changing conservation biologist Dr Jeremy Shelton’s vision for the future is accurate, that will be the reality if stakeholders like us do our bit. Tudor Caradoc-Davies interviewed him for issue 29 of The Mission.
“I’m embarrassed to admit that, until about five or six years ago, I wasn’t really familiar with the large, indigenous freshwater species that existed in my own back yard here in the Western Cape of South Africa. I knew about Clanwilliam yellowfish, but sawfin, witvis and sandfish weren’t really anywhere on my radar. I knew nothing about which river systems they occupied and I was oblivious to how threatened they are.
Now I know a lot more about these fish. That’s in part thanks to the fishing friends I hang out with, but largely thanks to the work people like Jeremy Shelton do. A freshwater conservation biologist and visual storyteller, perhaps you know Jeremy as one of the brains behind initiatives like the Saving Sandfish project. Maybe you’ve come across him deep in the mountains snorkelling the streams and conducting experiments on the fish they hold. Or it could be that you’ve thrown your bra or jocks at him when he was noodling out a crazy beat on the Djembe drums and shakers front stage at a West Coast Wolves concert. Whatever the case, we’re fans of his work because, not only is Jeremy educating people like me, but he’s taking the conversation around freshwater conservation beyond just protecting and conserving these ecosystems. He’s promoting a different future for them altogether.
I remember meeting Jeremy at the Cape Piscatorial Society (CPS) AGM a few years back when he, and a couple of colleagues from Cape Nature attended what are usually necessary, yet mind-numbingly boring, procedural affairs. To provide some context – the CPS is one of the biggest and oldest fly-fishing clubs in South Africa and it manages the trout streams of the Western Cape for members. To do this, the CPS works with Cape Nature (the regional nature conservation/parks management association in the Western Cape).
When Jeremy and his mates arrived at that AGM, a harrumphing chorus of negative old man energy ran through the room. The tension was as palpable as a bad drift on a clear glide. Why? Well, I discovered later that some members of the society assumed that, by the very nature of their work with Cape Nature and their efforts with indigenous fish, Jeremy and co. must therefore be rabid members of the anti-trout lobby. To be fair, that mistrust was somewhat understandable given that over the years there have been occasional anti-trout zealots in Cape Nature who have rattled their sabres at the fly-fishing community, threatening to eradicate our beloved salmonids by poisoning rivers with rotenone. Never mind that it was Cape Nature who originally stocked the rivers with trout over a hundred years ago.
The thing is, that animosity was misplaced, because Jeremy Shelton unashamedly loves trout. Considering he is one of the foremost protectors and fans of ‘fynbos fish’ (a neat descriptor for the endemic indigenous species that live in the streams and rivers of the Cape mountains), that may come as a surprise to some, but Shelton has spent a large proportion of his life properly nerding out on trout.
As a teen he spent every waking minute catching carp and bass and then his attention turned to trout, and in 1996 he joined the CPS, the very organisation where 20-odd years later at that AGM he was getting some mild stink-eye. In matric his biology project was on trout and in his tertiary studies they would continue to play a central role. After graduating from university with an Honours degree in zoology, Jeremy went travelling, spending some time in Canada visiting his father and fly fishing for salmon, surfing in Indonesia and generally doing that mid-twenties ‘find yourself’ thing. But then he returned to academia and trout.
“After travelling I had lost my interest in studying and in science. A friend of mine had, without me knowing, enrolled me in the conservation biology Masters programme at the University of Cape Town which, he thought, was the best thing ever. He put in an application for me and I was accepted before I even knew I’d applied. I was pretty pissed off initially but, about a month or two into the course, I realised that this was the best thing ever. This was because it was this shift from dry science into conservation biology which is a much broader field that included everything from teaching to communication to communities. That was the start of my real love for conservation.”
After his Masters, Jeremy did his PhD research on rainbow trout in the Cape. The further he investigated the streams and river systems, the more he discovered about the impact his beloved trout and other aliens (like bass) have on the indigenous ‘fynbos fish’ that were there in the first place.
Jeremy says, “I often get asked the question, ‘What’s the most important part of deciding to do a PhD?’ For me it was all about being passionate about the subject. I did a lot of reading about what happened when trout were introduced in other parts of the world like New Zealand, Australia, South America and other places where certain species of trout may not have been indigenous. There were some really interesting patterns, some of which were consistent across these different continents. To try and understand what was the relationship with trout and river eco-systems here in South Africa. I ended up designing a study that involved a blend of field surveys, but also some experimental work. The idea behind the field surveys is actually a very simple one. We were lucky enough to have this natural experiment here in the Cape where we’ve got a whole lot of rivers where trout have established and then a bunch of other, very similar rivers without trout. Often it’s just a waterfall that’s stopped them from getting in, or they just haven’t been stocked there. So, it was a really good opportunity to do this comparative study to see how the river ecosystem with trout, differed from that without trout.
“What we found was that, in the cases where trout really thrived, in the ecosystems that were ideal for them, it looked like they were probably displacing the indigenous fish. Because the trout and the indigenous fish feed on different things, that had some knock-on effects for the insects and even the algae in those food webs. In the places where trout did less well, you’d often find them co-existing with the indigenous fish and there the effects on the river food web were a lot more subtle. There are limitations with every approach and with a comparative study it’s very hard to tease out what the cause and effect of those patterns is. It’s more just about observing a relationship. That’s where the experimental component came in. We put some cages in rivers, some with trout, some with indigenous fish to try and really understand how these two different kinds of top predators would influence the food webs around them.”
As he spoke to me about his PhD it became glaringly apparent that while Jeremy acknowledges the impact of trout on an eco-system in the streams where they have established themselves, he’s also aware there’s not much point in trying to do something about it now. As with the introduction of trout in places like New Zealand or Argentina, it’s a case of that horse (or that fish) has bolted. Regardless, there are bigger threats.
He says, “I have always loved and respected trout. I still love fishing for them. It took me a long time to understand how something that seems to be thriving in these rivers and bringing a lot of joy to fishermen could also be potentially doing some ecological harm. I think that’s partly why I needed to go and really try and do the best research study I possibly could to get to the bottom of this and really understand what was happening underwater.
“In South Africa we’ve got a wide range of non-indigenous fish introduced from around the world either for fishing or as forage for those angling species. There’s definitely a varying degree of impact that these species will have on river ecosystems. Bass – smallmouth, largemouth, spotted etc – they are probably the most voracious. It’s very unusual to find situations where indigenous fish are still able to co-occur and co-exist with bass. Their predatory impacts are just so strong. With a species like trout, their impact is a bit more subtle and there are a lot of cases where they are able to co-exist with indigenous species. Their diet is a bit different to bass. Bass are really piscivorous whereas trout have a wider dietary range and will feed a lot more on insects. In many cases, particularly in areas where the conditions of the river might be a little bit marginal for the trout – that’s where you see the co-existence with indigenous species – and I think there’s a bit more of a natural balance in a lot of the places where trout have established themselves.
“One way to think about it is that trout need cold, clear water whereas some of the other invasive species like bass, carp and sharp-toothed catfish, are less concerned about the temperature or condition of the water. They’re able to spread pretty much throughout river systems until a big waterfall or something stops them. Generally, trout are confined to the cooler headwaters where they’ve been stocked. It’s not as easy for them to spread through entire river systems.”
What about the perceptions of tension and conflict between the scientists and anglers like me, with Gollum-level anxiety that our “precious” will be taken away? Put down the pitchforks and breathe easy. For Jeremy, the eradication of trout is not something he sees as remotely achievable or even desirable in most cases.
“I think there’s been a long history of scientists and anglers in this part of the world having quite energetic conversations around the place of trout in our rivers here in the Cape. The way I see it (and most scientists that I speak to today see it the same way), is that trout have a very important place in our riverscapes. They bring in a lot of eco-tourism value to the area and a lot of enjoyment for fly fishermen like myself. I think it’s completely unrealistic to think that there’s going to be this widespread removal of trout from rivers in the Cape… ever. The only time where trout removal from a section of river could, or should, be considered, is in a very specific situation where there will be a clear benefit for a very threatened indigenous species or a very threatened indigenous ecosystem. That needs to be a very well thought out project. Even if we wanted to remove an invasive fish from an entire long length of river, there’s just not the capacity to do it. In terms of those historic trout fisheries in this part of the world – the Witte, the Molenaars, the Holsloot, the Elandspad – there’s just no need. There’s a balance that’s been established there, they clearly have a lot of value recreationally and there’s no low-hanging fruit that by removing trout you directly benefit a threatened species.”
To find out about the future Jeremy envisages for large threatened indigenous species like Clanwilliam Yellowfish, Witvis and Sandfish, read the rest of his profile in issue 29 of The Mission below. As always, it’s free.