The Metachrotic Swan Song

Coryphaena hippurus is a large, wedge-shaped, pelagic teleost fish with a preference for tropical environments. It is a topwater ocean predator, lighting fast (achieving burst speeds of upwards of fifty knots), and capable of running down and sucking up large numbers of flying fish, a leading prey species. Known variously as dorado, mahimahi, and, confusingly, as dolphin (or dolphinfish), C. hippurus frequents sargassum mats and other surface aggregations of seaweed and flotsam in warm water, where it cruises flashingly in pursuit of just about anything it can get in its toothy mouth. The species is modestly sociable, but big males (which reach lengths of about four feet) tend to be solitary.

No one seems quite certain how these creatures ended up sharing a common name with mammalian delphinds, but it may have something to do with a shared proclivity for accompanying sea vessels. It was a habit that, from early on, got the dolphinfish in trouble, since they are relatively tasty. Here is the seventeenth-century English naval adventurer John Poyntz on their culinary virtues: “They are taken with the hook as we sail around the island; some of them two or three feet and more. They are delicate food, and make a fine Scaveche.” But that wasn’t really what distinguished them from the other finny critters that could be trolled up around Tobago, a lot of which tasted pretty good fricasseed in the Portuguese style. The special mystique that attached to C. hippurus was a function not of the gustatory pleasures they afforded, but rather of the improbable occasion these briny beasts offered for splendiferous meditation upon death.

Poyntz was one of the earliest English commentators on the dramatic phenomenon of their passing, noting with wonder that “when their lives expire, they reflect a tincture of what presents unto them.” It is a cryptic formulation. What did Poyntz mean, exactly? It is possible he himself was not quite sure. Those who witness the very-difficult-to-describe frequently offer testimony simultaneously obscure and pregnant. Did the captain wish to express that the bodies of these green-blue-silver-gold sea creatures blinked, at the moment of their deck-demise, with signs of what they were experiencing? Which is to say, that they showed forth their dying, visibly, dramatically, and in a manner that elicited, as he put it, “admiration”? Yes. Probably. It would make sense, since the death throes of a dolphinfish are a shocking, motile riot of color, which nearly always culminates in an abrupt draining to livid pallor. The animals’ ordinary metachrotic physiology (its ability to change colors responsively and in real time) comes unhinged in those final moments, producing remarkable effects. Allusion to this spasmodic spectacle—which would become a romantic obsession across the long nineteenth century—would seem to be the general thrust of Poyntz’s terse notation. Though something else lingers in his vexed phrasing. One senses he may be trying to say that, at the instant of its passing, a dorado, for a fleeting moment, becomes the chameleon-mirror of its immediate conditions—that one could catch in its bright sides an ephemeral glint of everything the dying fish saw with that cold gaze set unblinking on the hollow sky.