River Monsters
Page 5
Unlike piranhas and sharks, wels don’t have teeth that cut; instead, they swallow prey whole. A hypothetical sixteen-footer would have a mouth two feet in diameter, wider than my shoulders. The depth of the mouth cavity would be about three feet, but it could engulf an animal twice this length because wels, like many fish, can open their throats to take prey right into the stomach, which extends the whole length of the body cavity, almost as far as the vent. Such a fish, then, would be capable of swallowing an adult human. And like any fish that swallows large prey, they would take it down head-first, as most animals slip down more easily in that direction.
But fish well short of man-swallowing size inflicted the bite marks on the Schlachtensee victims. Typically the marks were about seven inches long, indicating a fish measuring about five feet and weighing around fifty pounds. But the historical accounts of human body parts being found inside wels stomachs raised the possibility of another feeding strategy. Could they drown and dismember large prey and then swallow the pieces in the same way that a crocodile does?
I am nearly six feet tall and weigh 175 pounds, and normally I can handle a fish out of water that I have brought to land or into a boat, even if it’s bigger than me. In its home element, though, it’s a very different story. I remember seeing a report about a diver in a Scottish sea loch who got caught in some fishing line that was attached to a conger eel. He was dragged from the shallows down to 150 feet before managing to cut himself free, whereupon he made an emergency ascent and then blacked out. Later it emerged that other divers had previously seen this eel, and the point is that it wasn’t enormous: just 40 pounds. So a full-grown man, used to being in the water and equipped with dive fins, had been unable to resist a fish a quarter of his size. Without his air tank and knife, he’d have been a goner. So the story I read about a wels pulling from his boat and drowning a young Polish man—who was fishing with his line tied to his wrist—does have a ring of truth.
So how big—in real numbers, pounds and feet—would a wels need to be to overpower a person in the water? To find out the pull that would be necessary to pull me under, I attached weights to myself until I couldn’t keep my head above the surface. It turned out that a downward pull of just thirty pounds will do it. Then I attached a cord to my waistband and swam against a spring balance to see how much horizontal force is needed to pull me backward. The figure was about the same. So what size wels would exert a pull of thirty pounds? The answer is not thirty pounds.
Although anglers set great store by fish weights, fish (with a few exceptions) weigh nothing in the water. You could hang a dead fish, of any size, on your leg without risk. This is why you don’t have to use twenty-pound line to catch a twenty-pound fish. In open water you can land a fish this size with a breaking strain of three pounds as long as you have plenty of it. You let the fish swim around against just enough resistance to keep it moving until it tires itself out and floats belly-up. Then you gently pull its weightless, buoyant body over your landing net or within grabbing range. But if you try to stop the fish when it’s running, to hold it from a sunken tree or boulder, it will snap the line. This is analogous to the difference between a boat with its motor stopped, which you can move with your little finger, and the same boat with its motor running. What you feel is not the fish’s weight but rather its muscular force and momentum. In general, this is proportional to size: a big fish pulls harder than a small fish. But some species pull harder for their weight than others, depending on body shape, fin area, muscle volume, metabolic rate, and so forth.
As far as I’m aware, there is no accurate data on what different fish pull. Scientists have better things to do. So I’m resorting to educated guesswork here that is based on what line strengths are necessary for “hit and hold” fishing in still water. Going on this, I estimate that, from a standing start, most fish can pull between one-third and half of their weight. (The figure will be higher if they already have some momentum.) So to exert a pull of thirty pounds—the force needed to pull me under or overpower me in water—a wels would need to be only sixty to ninety pounds. In other words, it would need to be only half my size or even less.
Based on this, the fish that attacked the swimmers in Schlachtensee was borderline size: maybe capable of pulling a person under, or maybe not. If that was its intention, it would have to “suck it and see.” I spoke to two of the victims, Jonas Wegg and Katharina Saxe, and neither of them was pulled under, which suggests they both had a lucky escape from a fish that was not quite big enough to pose a real danger. But bigger fish are in the lake, and neither of the victims goes swimming there anymore.
Something else they both said was very interesting. In the popular imagination, big fish live in the deepest water, but these attacks happened in the shallowest part of the lake, almost shallow enough to stand up in. Also, although wels commonly feed in shallows at night, the attacks happened in broad daylight. At first this would appear to give the wels an alibi, and indeed some biologists have expressed doubt that the attacker was a wels, but there is one reason why wels would be in the shallows at that time of year.
Summer is when wels breed, and unlike many other fish, they don’t just shed their eggs and abandon them. They lay them in a nest in the bottom weed and the male then defends against all comers.
“For this particular catfish it was a huge stress to guard the nest, when it had all those swimmers around,” Dr. Christian Wolter, from the Leibniz Institute of Freshwater Ecology and Inland Fisheries, told me as we rowed a boat in the area where the bathers were bitten. This was the only shallow, weedy water in the lake, apart from the extreme margins. The fish didn’t have anywhere else to breed. In his opinion, these incidents weren’t attacks but rather acts of self-defense.
I’d come prepared to fish for something with a large, unsatisfied appetite. Even though this assumption now appeared wrong, to come all this way and not cast a line would have been equally wrong. So I teamed up with a local angler called Horst, a retired butcher with a penchant for yodeling while he fished, and we spent an evening offering up half-pound crucian carp on the drop-off into the deep hole at the top end of the lake. We didn’t catch anything, but even blank sessions teach you something. In this case it lent support to what local anglers said about the existence of a very small head of wels here. This in turn chimed with what Dr. Wolter said about the difficulty wels have breeding here. All of this seemed to add up. The Schlachtensee wels are not man-eaters, just caring parents.
But what about those old stories of corpses and body parts? They come from a time, long gone, when wels were much more numerous and reported at massive sizes, so we’ll never know for sure how big they grew or just how predatory they were. Or maybe we will because, in a few places, the species is making a dramatic comeback. ...
Nowhere today holds as many big wels as the Rio Ebro in northern Spain, where hundred-pounders are commonplace and an increasing number go over two hundred pounds. Wels are not native to the river but were introduced just thirty-five years ago in the mid-1970s. Their phenomenal success here can be attributed to three main factors. First, the water is much warmer than their native rivers, so they feed and grow year-round with no shut-down period in winter. Second, they are aquatic golden geese. The local economy is now based on fishing tourism, so these fish are worth more alive than dead, and the fishing is, almost exclusively, catch and release. Third, the river is stuffed with food: not just the carp that were here originally but also the tons—literally—of high-protein bait that visiting anglers tip in the water. The Ebro was a place I had to check out.
Most catfish are omnivorous and are caught on baits such as worms, dead fish, or mussels on the bottom. But the big Ebro wels catfish are highly predatory. Until a few years ago, the preferred bait was live carp or eel. The carp were typically around five pounds, but there are stories of people using twenty-pounders. To keep the bait in the desired spot, a few yards of “weak” line, typically twenty pounds breaking strain, were attached to a swive
l above the bait and then tied to a tree branch on the far bank or a large buoy anchored in the water. When the angler tightened the line between the vertical rod and the anchor point, this would then suspend the bait just under the surface.
Wels find live prey by homing in on vibrations. Although fish ears have no opening to the outside or sound-gathering funnel like ours, catfish hearing is highly sensitive thanks to a series of small bones linking the ears to the swim bladder. In this way they use this large buoyancy organ as an amplifier. In addition, they use their lateral line, the sunken canal down each side of the body into which protrude jelly-covered hairs, which move and send nerve impulses in response to pressure changes in the water. So a fish tethered near the surface, even on the other side of the river, is an unmissable target. In fact, their remote sensing is so acute that experiments have shown wels to be capable of tracking down small fish by following the wake they leave in the water.
But live-baiting is now banned on the Ebro largely because fishermen were bringing in bait fish from outside, which carried the risk of spreading disease. Some would also argue that, in these enlightened times, this method is questionable from an ethical standpoint. But if the wels’s predatory reflexes are all they’re cracked up to be, they ought to hit a lure. To test this out, I spent an afternoon trolling in the “upper lake,” which is above the hydroelectric dam just upstream from the Ebro’s confluence with the Rio Segre. I think it’s true to say that hardly anyone fishes moving baits for any kind of catfish, but such a near-total disregard of their predatory side smacks of preconception or even prejudice. Wels are not sleek, streamlined fish like pike or salmon, and their sluglike looks suggest a nature that is equally sluggish. And although angling should be a lifelong lesson in open-mindedness, anglers on the whole judge catfish by their looks. In my case, however, I had open-mindedness forced upon me. In 1982, while fishing a lake in India, I cast a shallow-diving plug at a large swirl in a muddy bay and hooked a fish that, after an arm-wrenching fight, turned out to look disconcertingly like a wels. A closer look revealed a more silvery coloration and proper teeth, identifying it as a mulley (Wallagu attu). It weighed around twenty pounds, and to prove it was no fluke, I caught three smaller ones later. Locals told me it grows to over one hundred pounds but then added, to my lack of surprise, that such fish are an extreme rarity nowadays. Then, when I went to the Amazon, I caught surubim catfish (Pseudoplatystoma fasciatum) on plugs. These are beautiful, firm-bodied fish with battleship-like gray-and-black Rorschach patterns on their flanks. To begin, this was “lucky dip” fishing, trying all sorts of lures at all depths to find out what species were down there. Over time, however, my approach became more targeted, and what worked best for surubim was a slow troll, with the rod wedged under one knee and over the other leg and then the clutch loosened right off as I slowly paddled.
So trolling for wels didn’t seem too incongruous. Using the sonar to read the bottom, we swam the deep-diving Luhr-Jensen Fingerling as close as we could to the rock tumbles and pinnacles on the edge of the deep central valley. The first couple of times the rod kicked, it was zander, one a shiny, green, spiky-finned four-pounder. When the wels took, though, there was no doubting it, and once we’d survived the first heart-stopping moments, when fish and boat were traveling in opposite directions, the light rod struggled to bring it up. In the end I confess I was slightly disappointed that the wels wasn’t quite one hundred pounds, but a ninety-pounder is still a lunker on a lure. More important, though, was what it proved to me: that a hungry wels will hit a moving target.
But that fish hit in an artificial lake, in still, clear water. To test their responses in more realistic conditions, I booked a small rowing boat and a local guide, Enrico, and put in a few miles up the Rio Segre. Here the water was brown and bowling along in places at a fast trotting pace—hardly catfish water in most people’s minds. Bait was what Enrico called a “yummy fish,” six inches of soft, white plastic with a large single hook threaded through it. What followed was some of the most demanding and exhilarating fishing I’ve ever done. As the treehung riverbank blurred by, the aim was to spot slacks and eddies on the edge of the current and land the lure in them, as close to the side as possible. The difference between a perfect cast and a disastrous hangup that breaks the line—because in this current, there’s no going back—is about six inches. It took me a while to get the hang of it, keeping my feet as the boat spun and bumped down shallow rapids, while also scanning both banks—and all the time avoiding the camera boat without looking at it. At first I was cautious as I found my range. Then I started getting in some good shots in some good places, but I had no takes.
Then I hit on the vital detail. On landing the lure in a bank-side pocket, I left the reel open a fraction longer, to let the lure sink, then tightened and twitched it alive. Bang! Something plunged on the line as the boat kept barreling downstream and the drag yelped. Instead of the expected loud crack, I heard the painful reedy sound of line scything through water as the fish was dragged from its holt and started to follow us down. Then it was no longer there. It happened so quickly, this double dose of disbelief. I felt a certain sickness come over me—that aching feeling of loss and not knowing. But I couldn’t dwell on it because I knew now what to do, and more lies were passing by. Soon I was absorbed in renewed casting, and I hooked another fish. But that one got off too. Then there was the bridge ahead, where we would have to get out. I was bitterly disappointed and tried to give myself some solace by blaming the borrowed gear: a combination of soft rod and thick wire hook. The fish didn’t feel huge, maybe fifty pounds, but what memorable catches they would have been from water like this! You can keep your peacock bass, for all their brash Amazonian finery, which you fish in the same general way but at one-tenth the speed for one-tenth the rod-bending poundage. I told myself that one day I’d come back with a beefy bait-casting rod and multiplier reel and with my casting already sharpened so I could simply look at the spot and the cast would go there, like a basketball clearing the ring. But in a way all of this was beside the point. As much as any scientific paper, those hookups confirmed that wels are supreme predators, capable of detecting and seizing prey in turbulent zero visibility. What’s more, despite their reputation as bottom feeders, they are very switched on to possible food from above, which in fact is totally in keeping with their protruding lower jaw and upward-looking eyes. And to grab potential food this quickly, their reaction has to be an unthinking reflex: grab first, ask questions later.
But if there’s easier food around, they’ll go for it. Like all animals, constant biological accountancy, where the currency is energy, drives their behavior. Why chase food if it’s served up on a plate? Anglers on the Ebro also make a similar decision: why chase the fish if they will come to you? And, in a way, a deal is struck. Now, following the livebait ban, the most popular method is a half-dozen walnut-sized fishmeal pellets offered on the bottom. Wels find bait on the riverbed by following chemical trails in the water, trails they sniff out using the taste buds that are spread all over their bodies. (Some say that a catfish is like a giant tongue.) These chemical receptors are most concentrated on the whiskers. Together with four short whiskers on the chin, wels have two long ones on the upper jaw that they can extend to either side in front of them. This, we may suppose, makes their remote tasting strongly directional. They likely home in on food by turning in the direction of the stronger reading.
Bottom fishing for wels, Ebro style, bears more relation to marine beach fishing than to most freshwater fishing. Each rod is set in a vertical holder, and, by means of a small rowing boat, the bait is deposited 100 to 150 yards away along with sixteen to twenty ounces of lead to anchor it and a bucketful of loose pellets to lure the “cats” in. The line is zero-stretch braid with a breaking strain of 150 pounds, and the reel is screwed up tight. When the rod folds over or springs back straight as the line falls slack, this signals a take. In either case, there’s a tinkling of the bell clipped to the rod-tip.
The little sound is insignificant, but after a couple of days it has everyone reflexively scrambling, kicking over cups of tea and falling over film kit.
A flicked flashlight beam shows my rod is straight—a slack-liner. I grab it and wind up the slack. Yes, there’s a weight there that isn’t the lead, so I heave back as hard as I can. “Try to pull its head off,” is the unsubtle advice of the guides here, but with all that line out, anything less will just bounce the hook feebly off its jaw. The next moment, however, I’ve lost my balance and I’m being dragged on my backside toward the water. The only thing that stops me going in is a slab of rock that I hit with my feet. Some fishermen here end up with their companions hanging round their waists, but at least I’m spared that indignity. To my right is a large weedbed. If the fish kites round this, I’ll never get it in, so once I feel it coming my way, I can’t let up for a moment. There’s the sound of something breaking the surface, and at first all I see is its head—about a foot across. A hand grips its lower jaw, and then another hand, very quickly, as it tries to twist. The movement is exactly like a crocodile’s “death roll,” and I can easily see now how this could potentially drown a victim or rip a limb from a corpse. With its mouth unclamped from grazed hands, we zip it into a nylon body bag, and it takes three of us to drag it up onto the bank.
The thing weighs a massive 153 pounds, but my guide, Jason Toye, has seen many fish this size. He says the fish just keep getting bigger and bigger, possibly by as much as 5 to 10 pounds a year with no signs yet of any slowing down, although being precise is difficult when you’ve got fish that can “put on” 20 pounds in a few moments simply by inhaling a carp. (In the two years since I fished there, the record for the river went up by over 30 pounds. At the time of writing, it stands at 246 pounds, 14 ounces—an 8-foot, 2½-inch fish caught in September 2009. Meanwhile the biggest authenticated wels from anywhere was from Italy’s River Po in June 2010, weighing 250 pounds and measuring 8 feet, 2 inches.)