Tuesday, June 18, 2013

Book review: Swordfish

Swordfish: A Biolgraphy of the Ocean Gladiator
by Richard Ellis
University of Chicago Press, 2013

I never thought the billfish, impressive and tasty as they are, were especially interesting except to fishermen. Richard Ellis, as usual in his books on marine life (it's well known I am a fan of his work, so I'll state that up front), shows us differently. The billfish are an amazing bunch, and the swordfish is their king (or queen, since the largest specimens are always female). It is considered the most prestigious trophy in the sportfishing world and has been fished commercially since at least the time of the ancient Romans.

As Ellis demonstrates, this is a fish so perfectly evolved for its niche that is has, aside from humans, no real competition. It has a global range but constitutes only one species, which is the only species in its family. It can dive deep, 900m or more, in pursuit of squid, or it can massacre baitfish at the surface. It carries a weapon unique in the animal kingdom, a true sword with sharp edges used to cut, slash, or disable a wide variety of prey. It has superb vision, with eyes that can be as large as a grapefruit and can pick up tiny flashes of light from prey in the surface waters or in the deeps. It can be well over four meters long (maybe even five) and weigh well over half a ton, and it has a complex heater that warms the brain and eyes to keep the fish "thinking" and seeing at its best whatever the water temperature.

Ellis shows, too, there are still mysteries surrounding this conspicious fish. While some rammings of boats (and humans) seem unintentional, there are cases where a swordfish has deliberately rammed something (like a whale) it can't kill, let alone eat. Swordfish have also attacked huge inanimate objects - ships, floating bales of rubber, and, most famously, the submersible Alvin (which surfaced with the wriggling swordfish still lodged in its hull joint). We simply don't know why. Ellis also dismantles some myths. We now know the swordfish does not impale prey using the sword tip, at least not deliberately.

Along the way, Ellis drops tidbits of interesting data: I never knew that all the swordfish in the film The Perfect Storm were props, or that Frank Mundus (the model for Quint in Jaws) wore different colored socks so (he told clients) he could remember port from starboard. He discourses on other well-armed fish, such as the sawfish and the other billfish, and also looks at the narwhal, possessor of the only weapon more impressive than the swordfish's (although it doesn't normally use its tusk as a weapon at all).

Ellis hits on the themes of overfishing and conservation several times in the book, and returns to the matter in detail at the end. This part doesn't always flow well: Ellis will drop a statistic or a fact and return to it a page or two later after talking about something else. The chapter on mercury levels seemed out of place, coming too early in the book rather than being placed with the other environmental discussions. (The only actual (if trivial) mistake I spotted in the book was a reference to "Captain Aronnax" watching swordfish from Jules Verne's Nautilus: I was unaware that a mutiny had occurred and Nemo had been deposed.)

Ellis doesn't think we're as concerned about the fish as we should be. The IUCN doesn't consider the species Threatened, and the catch in the North Atlantic has rebounded after a shutdown for mercury posioning and several environmental campaigns. Ellis argues we should be more alarmed, though, by the drastic drop in the average size of landed fish (down to a miniscule 90 pounds) and notes that government regulations on minimum sizes don't help: it just means more dead fish are discarded from the longlines used in swordfishing. While some giants are still hooked, there's no question the total global biomass is down to a fraction of what it was a century ago, and the situation is drastic in the Mediterranean.

If the swordfish needed a biographer, it was lucky to get Ellis. This may not be a perfect book, but I was, well, hooked firmly enough to read it through twice. I came away with a much greater appreciation for one of Nature's marvels. The 27-page biography adds to the value of this accessible and well-researched work.

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