ANSWER: Dave, that extremely characteristic and quite long threadlike extension to the dorsal and anal fins can only mean that you caught the aptly named threadfin jack (or trevally), Caranx otrynter. Found from Bahia Magdalena, southern Baja, to Ecuador, including the lower and central Gulf of California and the Galapagos, this jack lives in estuaries and along the open coast, both around reefs and over soft seafloors. The species, which grows to about 26 inches long, ranges from the surface (occasionally with its back out of the surface in nearshore waters) down to depths of more than 300 feet. I usually see this species in pairs or groups of several to 15, sometimes rooting about in the seafloor and other times actively pursuing prey (which includes fishes and small crustaceans) in midwater. Threadfin are taken both by hook-and-line and in various nets, and are sold mostly fresh, although some are salted for later sale. No all-tackle world record for the threadfin jack has yet been established with the International Game Fish Association for this species.