River Monsters (39 page)

This one, three or four years old, was just a juvenile, not yet quite ready to descend to the sea to start breeding. Once in salt water, the picture is, if anything, even more hazy. Sawfish
don’t turn up very often off the Australian coast, but when they do, the sizes can be astounding. In 1926 a Sydney newspaper reported an eighteen-foot, two-inch fish harpooned in coastal
shallows. Malcolm Douglas, croc hunter turned celebrated conservationist, once found a massive one in an illegal net in King Sound, though the fish was eventually left high and dry by the falling
tide, with Malcolm and his mud-trapped companions unable to free it in time. (He also told me of the time he watched a sawfish feeding, slashing a shoal of mullet with its rostrum ablur and then
circling back around to suck in the hacked and mutilated fish. In captivity, they’ve been seen to eye up individual fish before cocking sideways and hitting their target with a movement like
a karate chop.) In 1985 Owen Torres, a retired pearl diver of Aboriginal-Filipino-Sri Lankan-pommy descent, caught a fish bigger than his seventeen-foot boat while up Willie Creek near Broome,
although he never saw a single sawfish during all his time underwater. And in the same year a coastal fisherman I spoke to got a twenty-three-footer caught in his barramundi net.

My mind returned to those fish Mitchell-Hedges caught, and armed now with the length and weight of my fish (seven feet long and seventy pounds), I did a back-of-envelope calculation. Most
unreliable reports (such as those for fifteen-foot arapaima and sixteen-foot wels catfish) give weights that are far too low for the fish’s length. But Mitchell-Hedges’s weights are
spot on. So perhaps I’m more inclined now to believe his report of a thirty-foot fish weighing over five thousand pounds.

I pause for a moment and try to turn those cold numbers into a mental picture of a real, live, swimming animal, but my imagination, which I am used to sending into the unknowable depths, cannot
summon or find it. Even though I’ve now touched a live seven-footer, a sawfish the size of a boat is too big and unreal to fit inside my head. Maybe a two-and-a-half-tonner is still out there
somewhere, but I doubt we’ll ever know for sure. Given the state of the world’s sawfish population, such giants will probably never return.

19

CAPTAIN COOK’S DEVOURER OF MEN

When Cook made his wind-powered voyage from England in HMS
Resolution
, he went via the southern tip of Africa and the Southern Ocean, taking nearly nine months. When I went to New Zealand
in March 2010, I had a much easier time of it. I left London’s Heathrow airport in an Air New Zealand Boeing 747 one afternoon and touched down in Auckland, on North Island, twenty-six hours
later, having briefly stopped to refuel in Los Angeles.

From six miles up, if there’s not too much cloud, you can see where you are. Sometime before landing in LA, I looked down through darkness and saw the bright grid of Las Vegas as the
setting sun poured molten red light over the western horizon. Most of the other passengers dozed or watched films. Then a series of bright stepping stones led to our destination.

But the journey’s second leg was entirely over ocean, a wide empty space where navigation has to be done by instruments. Sensors embedded in the aircraft feel the gentle pull of the
earth’s magnetic field while others hear whispered signals from satellites. Others monitor the weight of remaining fuel while an electronic brain continually recalculates its position
relative to the programmed destination. In Cook’s time, as now, a vital navigational instrument was an accurate and reliable timepiece. Even without this, he would have been all too aware of
the slow passage of days and nights on his voyage. But when you hurl a human body-clock at 500 mph through the earth’s time zones, it goes completely to pieces. If this is in an east-to-west
direction, fleeing the sun, it stretches time, lengthening both day and night. So although outside was dark, inside I was awake. On the screen in front of me I watched as we crossed the
International Date Line and passed instantaneously from March 13 into March 15. This vanishing of an entire day was something that my tired but wakeful brain couldn’t comprehend. But the
place on the map where it happened, the Kermadec Trench, south of Tonga, is home to far greater mysteries.

The indigenous people of New Zealand, the Maori, arrived by sea from Polynesia only seven hundred years ago – a much more recent colonisation than that of Australia, which was fifty
thousand years ago. One clue to the identity of Cook’s beast comes from Maori folklore, which is full of mythical beings called
taniwha
(pronounced tun-eefa). These shape-shifting
creatures are notoriously hard to pin down. Maori elder Te Pare Joseph told me they are spirits that protect places, and if they are not acknowledged properly, by placing the correct offerings,
they can be dangerous to humans. Sometimes they inhabit a harmless-looking log or a rock, but when these slippery customers come more into focus, they commonly take the form of a giant eel.

Like the serpent in the Garden of Eden, the eel in Maori legend is a mischief-maker, an emissary from heaven who was banished to wander the seas and rivers after pursuing its own agenda of
cuckoldry and seduction when on a mission to Earth.

The most obvious characteristic of all eels is body shape: long and thin, just like snakes. This could give rise to mistaken identity, particularly as most observers wouldn’t want to get
too close. To improve propulsion, both dorsal and anal fin are greatly elongated and fused with the tail to form a continuous paddle around the rear half of the body. Most eels are marine, such as
the congers and morays that lurk in reefs and shipwrecks, but sixteen species are found in fresh water, in temperate and tropical river systems around the world, except those draining into the
eastern Pacific and south Atlantic. So there are no eels in South America, western North America, or West Africa (although, confusingly, some unrelated long-bodied fish are commonly called
eels).

Along with their body shape, the main characteristic of freshwater eels is behavioural. Every year there are two mass migrations: of adult eels swimming downriver on moonless nights to the sea
and of elvers, their tiny young, swarming in their multitudes in the opposite direction. This is something that humans have been aware of, and have exploited, for thousands of years. Eel spears,
traps, and bones have been found beside Lough Neagh in Northern Ireland from the pre-agricultural Middle Stone Age of 6000
BC
. Archaeologists have discovered a five
thousand-year-old eel-fishing camp in Nova Scotia. The Maori, too, have been trapping and spearing eels for centuries, smoking the surplus from the seasonal glut to see them through the lean times
in between.

For recreational fishermen, however, the eel has the distinction of being the fish that most of us don’t want to catch. I remember them with anything but fondness from my early days.
Foot-long ‘bootlaces’ swallowing the worms and maggots intended for other fish and tying themselves and the line in knots. Unhooking them was the devil’s own job, as they were
impossible to hold still and coated our hands with slime that took forever to remove. Bigger eels, however, attract a select band of devotees. The British rod-caught record is eleven pounds, two
ounces, and good-sized ones are sometimes caught accidentally. I once caught a yard-long three-pounder from an old dammed lake when night-fishing for carp with earthworms, and I thought it was a
much bigger carp for the first few seconds until I realised that there was a very different feel to this fish.

This was a European eel (
Anguilla anguilla
), a species that had mystified naturalists for centuries. Aristotle, in the fourth century
BC
, noted that they migrate
to the sea in autumn. But where do they go then? And where do they come from? If you observe most freshwater fish long enough, sooner or later you will see them breed: carp churning up lake
shallows or salmon thrashing in gravelly redds after their heroic journey from the sea. But nobody had ever seen eels breed. The idea took hold that they arose from ‘the entrails of the
earth’: spontaneous generation. The Italian naturalist Francesco Redi was the one who, in the seventeenth century, first published the correct basics of the eel’s life cycle: that the
eggs are laid in the sea and then the elvers ascend rivers. But nobody had ever found eggs inside an eel. Sigmund Freud, when he was a student of anatomy, was one of those who looked. The time he
spent staring at eels – firm, smooth, muscular – while he dissected four hundred of them possibly influenced the future direction of his career.

The breakthrough came in 1897 when the Italian biologist Giovanni Grassi announced the capture, from the sea near Sicily, of a male eel carrying sperm. He also discovered something else:
swarming in the sea were transparent creatures, shaped like willow leaves and known as
leptocephali
(Latin for ‘thin heads’), which everyone else assumed were simply small,
strange fish that didn’t grow very big. But Grassi suspected they were the larval stages of something else. He noted that the number of vertebrae – 115, give or take one or two –
matched that found in freshwater eels. On keeping some under observation in an aquarium, he subsequently observed the metamorphosis of thin-head into eel.

However, all of the thin-heads that Grassi found were fully grown, about three inches long and almost on the point of metamorphosis. Because there were no smaller ones here, they must have come
from somewhere else, but nobody knew where. Danish scientist Johannes Schmidt was the one who finally discovered the eel’s breeding grounds, three thousand miles from Europe in the Sargasso
Sea, a deep, still patch of water north of Puerto Rico and east of Florida. He did this by towing fine nets in different areas of the north Atlantic until he located the region where the smallest
thin-heads were found. These were one-fifth of an inch long (five millimetres), and for the purposes of general textbooks, the European eel’s life cycle is now a closed case – except
nobody, to this day, has ever observed eels breeding in the wild.

The first eels that ventured into fresh water are thought to have evolved in the ocean near present-day Indonesia. This population split and dispersed on the changing ocean currents as the
proto-continents drifted towards their present positions. But why these eels ended up spending most of their lives in fresh water is another mystery. Rivers are no-go areas for most sea fish, but
like bull sharks and rays, eels were able to make this transition. And once inland, there must have been some advantage to make them stay. Perhaps they found better food supplies or more hiding
places or fewer predators.

New Zealand is home to three species of freshwater eel, the largest of which is the longfin eel (
Anguilla dieffenbachii
). This is said to be the largest freshwater eel in the world, a
sliver of information that has been in the well of my memory for many years. And, on reflection, there’s every reason why this should be true. Adrift on the fringes of the shifting
continents, New Zealand is ecologically unique, having been beyond the spread of mammals until humans arrived. So huge flightless birds, including the quarter-ton moa (
Dinornis robustus
),
came to dominate the land, and only the super-sized Haast’s eagle (
Hieraaetus moorei
) hunted these – until the Maori arrived. Underwater, the picture is similar, with few native
species. So the interloper from the sea has become the top predator, with nothing to hunt it as it slowly grows, waiting for its call back to the sea. But could this flesh-and-blood fish be the
creature behind Cook’s report of an eight-foot-long devourer of men?