Wednesday, July 23, 2008

Sarda helisaltator

Dervish Bonitos
(Sarda helisaltator), the most colorful of all mackerels, are found as far north as Panama on the Pacific. They are easily identified by their enlarged, fan-like pectoral and pelvic fins and long, square-tipped tails. Their oily flesh is not prized as food, and a captured specimen is more likely headed for a public aquarium than a dinner table. Traveling in schools, their feeding excursions often take them to the water’s surface, where they will leap out and execute the “dance” they are named for.

Although they cannot cover long distances like Beloniformes, Dervish Bonitos are able to keep themselves out of the water by their own impetus for roughly 30 seconds at a time. Their dance involves a combination of caudal propulsion (“tail-walking”) with the lift granted by rotating with fins splayed. The sight of dancing Bonitos is always impressive — especially on a clear day, when the sun’s rays glance off their brilliant green and violet scales. The spectacle can become grisly, however, should a low-flying gannet enter the picture.

While a Dervish Bonito’s bony meat is a possible meal for a seabird, gannets prefer its tastier, water-bound relatives. If a gannet scouting prey happens to glide over a Bonito whirling at full tilt, the fish — especially when driven by hunger — is likely to dart straight at the bird’s underside in a burst of hitherto-unseen energy. Using its small but powerful jaws (which are ringed about the lip by miniature bone “pikes”), a Dervish Bonito can tear into a gannet’s torso, remove the liver (likely its favorite collation), and be back underwater in seconds. Hence the nickname “gannetsucker” (although the Dervish Bonito is not a member of the completely-freshwater suckerfish family).

Dervish Bonitos are born with long barbels but lose them before maturity. The high forehead is characteristic of the male.

From: Hurbest S. Gomarding (Ph.D), The Hazel Marine Guide. New York: Brownish Press, 1956: p. 89.