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Dive Dry with Dr. Bill

#523: Yellowtail Turned Tail?

I did one heck of a lot of diving last year... logging more than three times the total number of dives from the year before. Yet last year some things were missing. With the unusually warm water of late summer and early fall, I would have expected to see a lot more predators coming in from the south. Yet I didn't see a single yellowtail and only a few barracuda. Perhaps the anglers saw a different picture. It did seem strange given the appearance of some rather unusual fish like the whitetail damsel and spotted porcupinefish up from Mexican waters.

I'm trying to edit the yellowtail segment in my cable TV episode about predators, yet I have so little footage to create it with. I've seen them in the past, but they were often too far away to image clearly. The only close ones I captured on tape were ones caught by local spearfishers or by anglers while on board a boat off Guadalupe Island where we studied great white sharks. I'll have to be very creative with the footage and the stills to complete this segment!

The yellowtail is known scientifically as Seriola lalandi but may be referred to as the forktail, mossback, amberjack or yellowtail kingfish.Some of my friends simply call it dinner. I've heard people mistakenly refer to it as a relative of the tuna which is in the mackerel family (Scombridae), but actually it is in the jack family, Carangidae. Other local members include the jack mackerel (yes, it is not a true mackerel) and the pilot fish which frequently accompanies sharks. When I dive in warmer waters (as I hope to this winter!) I see a number of their tropical and subtropical relatives.

Yellowtail have an elongated, streamlined body with a yellow to bronze stripe along the middle and a dark bar that extends through the eyes. Like many open water fish, they are countershaded with a darker bluish dorsal surface and a silver to white belly that makes it difficult for their predators to see them from above or below. The fins and large, forked tail are yellow... as might be suspected from their common name here. Reported lengths and weights differ widely, which may be a result of their worldwide distribution in tropical and subtropical waters... or the fertile imaginations of some anglers, at least with respect to the ones that got away! Maximum reported lengths ranged from five to over eight feet and weights from 80 to an unbelievable 213 pounds. Common lengths in southern California waters are about 2 1/2 feet with the maximum reported at four feet although some report larger ones to five feet.

Along the west coasts of the "New World," they have been recorded as far north as British Columbia south to Chile, although these extremes are undoubtedly seasonal. Yellowtail enter our waters here in southern California from Mexico in spring and sometimes in winter. Their seasonal migrations are linked to changing water temperatures since they prefer a range 64 to 75 F. They are usually a pelagic species, swimming within 20 feet of the surface, but have been caught as deep as 120 ft and one report suggested a maximum depth of 1,000 ft.

Back in 2009 I observed a huge school of perhaps 500 yellowtail swimming past me at Italian Gardens. Earlier that day, local diver Jon Council had seen a similar school off Pebbly Beach heading in my direction. I believe this school was in spawning mode. Yellowtail mature sexually at 2-3 years (talk about the "terrible twos!") when they are 22-28" long. Most spawning occurs in the warmer waters off Baja from May to October with a peak in summer. During El Ninos or other warm water periods, they may spawn in southern California. According to Dr. Milton Love, individual females produce up to four million eggs per season.

Yellowtail munch on a variety of small, schooling fish including Pacific mackerel, sardines and anchovies. They will also "invite" their relative the jack mackerel to dinner. They also eat squid and pelagic red crabs. Anglers consider the yellowtail to be a a great sport fish, putting up a good fight for their size. The Chumash and other Native American tribes in the region caught them. Back in 1886 Dr. Charles F. Holder, co-founder of Avalon's Tuna Club, reported that large catches of yellowtail, including ones in the 20 to 35 lb range, were taken right from Avalon Bay.

Even fast swimming fish like the yellowtail can acquire irritating parasites. Few self-respecting cleaner fish would dare try to pick them off a yellowtail since they might become dinner in the process, just like few cleaners will take the copepod parasites near a giant sea bass' mouth... wouldn't be prudent! I observe other predatory fish like the kelp or calico bass rubbing their bodies on the bottom or the rocky reef to scratch their itches. I've filmed yellowtail doing the same. Sure glad in all my years of SCUBA diving I've never had a single parasite attach to me... although the senorita seem to think the hair flowing out under my hood is a tasty meal of thin worms!

© 2013 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 29, 10:00 AM weekdays and on Charter Communications Cable channel 33 at 7:30 PM on Tuesdays in the Riverside/Norco area. You can also watch these episodes in iPod format on YouTube through my channel there (drbillbushing). Please help me climb out of self-imposed poverty... buy my DVD's (see this link). Yes, take Dr. Bill home with you... we'll both be glad you did!

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Small yellowtail swimming, yellowtail speared for dinner by Tim Mitchell and a
horrendously wasteful catch of yellowtail fed to the sea lions long ago.

This document maintained by Dr. Bill Bushing.
Material and images © 2012 Star Thrower Educational Multimedia