Flying fish

Tony Gaston, in his Seabirds: A Natural History, speculates on escape flights of flying fish and flying squid, and it brings up something I need to investigate further:

The herding tactics of tropical tuna and dolphins may be an important factor in the development of short aerial escape flights of flying fish and flying squids, tactics presumably encouraged by the more rapid acceleration available to fish and squid in warm waters. A consequence of these escape flights is that some food becomes available to seabirds without contacting the water and this type of aerial foraging has been noted for tropical gadfly petrels, shearwaters, frigatebirds, tern, and the Red-footed Booby (Ballance & Pitman, 1999). Such opportunities are not available to cold-water seabirds. (111)

Now, I grew up in Los Angeles, and in the summers we would visit Catalina Island. The trip always involved an hour or two on the boat out of San Pedro, and along the way, we would frequently see flying fish. (I don’t recall seeing any flying squid, though.) The waters off L.A. are pretty darn cold, but nothing compared to, I suppose, the Atlantic (or Pacific) waters off Canada, which is where Gaston is from.

The questions I have are these:

  • Are there not enough flying fish off L.A. to be a resource for seabirds? (I certainly don’t recall any birds making meals of them, but then, it’s not like I was out there every day watching…)
  • Are the predatory fish off L.A. not able to stimulate sufficient volume of fish/squid needing to escape for them to become habitual prey items?
  • Are the waters off L.A. warm enough to qualify as providing “rapid acceleration,” which seems to be Gaston’s prerequisite for there to be flying fish in the first place?

One thing I’ve discovered since starting this thought process is that Catalina Island’s flying fish only fly in the summer, so there is definitely an element of heat and daylight involved; these fish must be migratory, and presumably follow their food resources, which must be limited by temperature or sunlight.

According to Wikipedia, the California flyingfish (either Cypselurus californicus, the genus name of which is not listed in my KPCOFGS, or Cheilopogon pinnatibarbatus californicus, of which the genus name, but not the specific epithet, is listed) is the largest species of the family. Apparently, adults are both epipelagic (meaning they hang out high enough in the water column for sunlight to penetrate, for there to be photosynthetic phytoplankton, etc.) and neritic (meaning they occur near shore [technically from the low tide mark to the edge of the continental shelf]). As such, they occur in those regions of the oceans most frequented by human observers (when was the last time you went below 200m deep?).

These fish are able to burst out of the water and glide (they don’t actually fly) thanks to their enlarged pectoral fins, which serve as airfoils. And, according to Gaston, temperature plays a role in their escape flights as well, providing them with enough metabolic energy for the demanding task of jumping out of the water and then staying out, working the air currents just above the water (the way many birds d0–most of us have seen pelicans surfing the air in front of the waves along the coast) to extend their glide, before eventually going back under (or being eaten by a lucky bird in the right place at the right time). Presumably they fly to avoid underwater predators; it must be frustrating to jump out of the frying pan only to wind up in the fire!

Which brings up a thought. Flying, frying. Maybe I should research frying fish for my next post? Or flame-broiled. Either way, yum!