Dive Dry with Dr. Bill

#522: The "Real" Halibut

Last week I wrote about seeing a veritable flying seaweed "magic carpet" in the dive park... shades of the Arabian Nights. When I first witnessed it more than a decade ago, I thought it was my first and only sighting of a gigantic Pacific halibut. Further detective work proved that it was not. Instead, it was a monstrous California halibut. However, since I took the time to write a column about its bigger cousin, I thought I'd better use it this week since they are occasionally seen in our waters! Besides, I'm off in the Bahamas filming sharks and I might not get back in time to write.

Of course I've seen Pacific halibut (Hippoglossus stenolepis) before... on TV when watching commercial fishermen haul in the big ones in the Gulf of Alaska, or on my dinner plate. Yummy!. The Pacific halibut has been given some other interesting common names: northern halibut, right halibut, genuine halibut and real halibut. Compared to its much smaller cousin the California halibut (Paralichthys californicus)... well, there just is no comparison. Pacific halibut are known to reach lengths of 8-9 ft and have weighed in at 500 with reports of ones up to 700 lbs. Males tend to be smaller and few exceed 80 lbs since they don't have to store millions of eggs.

This species has a diamond-shaped body that is elongate and somewhat slender but thick (with yummy steaks). No other flatfish has a tail like it.. it is lunate or moon shaped, being slightly concave. The California halibut's is convex or rounded. The body color is dark black, brown or greenish-brown with a white underbelly. The one I saw was definitely greenish in color with numerous blotches and other markings allowing it to camouflage well. The highly arched lateral line rises above the pectoral fin. The Pacific halibut is a true-blue member of the right-eyed founder family Pleuronectidae, although occasionally a few lefties will be seen.

If you encounter a small individual, the best way to distinguish it from a California halibut is by looking at the mouth. No, not IN the mouth since it is large and full of sharp, conical teeth. The jaw of the Pacific halibut extends just to the front edge of the eye while that of its cousin extends beyond the eye.

This species is uncommon to rare within safe diving limits. They may be found from 20 ft to as deep as 3,600 ft. You can bet the good doctor won't be looking down at those depths for anything, even mermaids! The decompression stops required would last longer than the years I have left on this planet! The Pacific halibut's geographic distribution has been variously reported, perhaps due to the extreme depths they may frequent. The broadest range has them living from the Sea of Japan, through the Bering Sea and Aleutian Islands down the West Coast of North America perhaps as far as Baja California. Unlike Dr. Bill, they prefer temperatures of 37-46 degrees Fahrenheit.

Pacific halibut may move into relatively "shallow" waters during summer to feed. Smaller individuals eat crabs and other crusty crustaceans while larger ones target fish. Other menu items include amphipods, hermit crabs, shrimp, clams, snails, squid and octopus. In turn they may be munched on by sea lions, seals, orcas, large fish, bald eagles, terns and even larger members of their own species!

In fall they retreat to deeper water to spawn from November to perhaps as late as March. Females begin maturing at age eight and all reach it at 20 while the males are "ready" anytime after eight years. Large females are reported to produce as as many as four million eggs. The eggs drift in the plankton at depths of 300-600 ft and hatch within 12-20 days depending on water temperature. The larvae continue to drift at similar depths for about six months. By early spring the migration of the eyes is complete and the young, some as small as less than an inch, settle in shallow waters such as bays. Females grow faster and live longer than males although the oldest recorded female was only 42 and the senior citizen male had reached age 55.

Pacific halibut were an important food fish for many Pacific NW Native American tribes. The flesh was preserved by drying and then eaten during the winter months. The first large-scale commercial catches began in the late 1880s off Washington and extended into the Gulf of Alaska as early as 1913. Now I love halibut, but I think I'll stick to our warmer waters and focus my culinary attention on our local sand dabs. They are more than a mouthful... even for me!

© 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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Images of the Pacific halibut (courtesy of NOAA) and my dinner plate with a tasty halibut steak on it.

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