Fishmail: Of birds and worms

September 27th, 2003

It’s odd how your perspectives change depending on where in the world you are. My hangovers, for instance, so apparently life-threatening in the comfort of my own home, seem almost welcome on a verandah in Queensland or a riverbank in France. The mere fact of dislocation from the normal daily pattern makes one look at the world in a wholly new way, even if your liver cells are screaming for mercy and your cerebral cortex shrinking by the second.

And so it is with more or less everything else in my life. I have only ever seen two ospreys in the UK, for example, despite years of looking out for them, and so the excitement at the prospect of seeing another never diminishes; just as the infrequent glimpses of a kingfisher still quicken my pulse, so too does the hope of seeing another one of these extraordinary birds doing its effortless, raptor-ish thing above a Scottish loch somewhere. But move me to the east coast of Australia, and my osprey tolerance is suddenly and sorely tested. The buggers are everywhere, doing things that you normally have to pay good money to see in wildlife books or listen to the breathless Attenborough describe on TV; catching fish, nesting chicks and just sort of loitering around insolently. The expression “Not more bloody ospreys” has been known to pass my lips more than once. An unworthy thought for a wildlife lover, you may think, but there you go.

Fortunately, my osprey ennui did nothing to affect my wonder in Australia in 2002, when I sat by a sleepy lagoon somewhere north of Sydney and watched one of these still-amazing birds blithely scoop up a fish and flap away with it, fighting off the attentions of a marauding flock of seagulls with the most casual wave of a large and powerful wing. I didn’t even pause to consider why it was that if these fish were so apparently plentiful and accessible, I hadn’t had a take for three hours – this was after all saltwater fishing, and everybody knows how pointless that is.

Cut to the river Wylye in Wiltshire in July, where I had a fabulous day catching fat, fit browns on very small grey dusters. (Bear with me here. There is a point to this diversion, of sorts). It was one of those rare days when the fishing universe seemed to be in some sort of harmony – the weather was good, the casting was delicate and accurate, the flies worked and the fish did what they were supposed to do. With one exception. One of these fish sat just under the surface, not feeding but nonetheless clearly active, and was the only trout I saw that day that refused to even look at a fly. While this is hardly an unusual occurrence – especially when the person holding the flyrod is me – I did wonder what was different about this particular specimen that made it behave so differently from its neighbours. And I thought about both of these occurrences this week as I read an extraordinary book that I think everyone should read.

It is called Parasite Rex, by Carl Zimmer, and it is about parasites. Now, I know that this doesn’t sound like an especially glamorous subject. Tapeworms and their ilk are not generally regarded as polite dinner party conversation, but I have long believed otherwise; in my university days I was obsessed with the little devils, and they led me to all sorts of interesting observations about fish in particular. I hadn’t realised that even quite big fish ate such small things, for example, until I started examining the guts of net-caught perch for a species of nematode worm in which I had developed an unhealthy interest – an observation that has served me well since then on those days when you start to lose faith in those size 22 suspender buzzers.

This book reminded me quite how fascinating the creatures that live in or on more or less every living organism are. (Just to drive home the importance of this subject, consider the extraordinary fact that fully 80% of all life forms on earth are parasitic, and that even parasites have their own parasites. Now think about what’s really happening when your tummy gurgles at inappropriate moments). It also reminded me that parasites modify the behaviour of their hosts in quite remarkable ways. Some especially dazzling examples of this involve worms that take over the brains of fish and force them to swim enticingly at the surface, thus making them easy targets for the birds that complete the parasite’s life cycle.

This is where our ospreys come back in, of course – and perhaps our Wylye trout too. Despite my interest in wriggly things that live inside fish, it had honestly never occurred to me that maybe the fish that I was failing to catch might not actually just be deliberately taunting me or feeding on something that I didn’t have in my flybox, but that it might actually be in the grip of an unseen invader. It had also never really occurred to me that it is the presence of these invaders that allow us to have ospreys and kingfishers and herons as part of our world – without the parasites to change the fishes’ behaviour, they might well go somewhere else for an easier feed. But these things are provably true in many fish and bird species, in many parts of the world.

If I have a point here, I suppose it is simply this: I have just never really thought hard enough about fishing at all. For most of us, the fish is the target, the end game; it is, if you let it become so, the principal source of joy and frustration to the exclusion of everything else. This week’s reminder that some of these things are so far beyond our control has been something of a shock after all these years, especially in the context of something as apparently nasty as a parasite. And the next time I come across an apparently uncatchable fish, I will spare a thought for what might be happening inside it – and what other marvels that may bring us.

One last thing. If you’re having fish for lunch, don’t forget to cook it properly. You really don’t want diphyllobothriasis.

 
Sean Geer (sean@fishmail.co.uk) is a freelance writer, journalist and fish pervert. He recently won the coveted Sexyloops Least Competent Fly-Tier award for the third year in a row, following a horrible accident with some deer hair and a bottle of red wine. In his spare time, Sean fails to write novels, makes barely credible origami fish and invents exciting new uses for tinsel.

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