by Buzz Owen   Special To The ICO

Matt Lum of Santa Barbara
Photo supplied by Buzz Owen
(Click picture to enlarge)

A giant abalone, taken off our coast in early August by Matt Lum of Santa Barbara, has the heaviest animal ever recorded by Buzz Owen, who has spent over 50 years studying gigantism in Haliotis (abalone) animals.

Owen said not only is it the largest, but it exceeds the weight of the second largest known animal by over 20 percent!  The reasons this particular animal reached such a massive size are not completely understood, but factors immediately apparent are a huge shell size of almost 11 inches in length, combined with a disproportionate width of about 9.5 inches plus extreme depth, the effect being somewhat like a giant, almost circular, deep salad bowl.

Beyond that, however, is a second reason:  the animal was so thick and massive that it couldn't even fit into this giant bowl-like shell.  Often such deep and circular shells are quite old, and harbor an aged and somewhat shrunken animal that only partly fills the shell.

For the past 29 years, Owen has observed large animal weights that have been taken by a number of other divers and himself pursuing abalone in the Gualala/Sea Ranch area, with shell size being of secondary interest.  Somewhere in the early 1990s, it was becoming apparent that the animal weights were steadily increasing in large mature red abalone, measuring approximately 9-10 inches in length.

The larger animal weight may coincide with two other phenomena which may be contributing factors:  reduced numbers of the large red sea urchin, which compete heavily with abalone for space and forage, and extremely abnormal development of male gonads in large mature males, which Owen has observed for well over 10 years now.

It is possible that the glycogen reserves the animal builds up during the late summer and fall are being used to build up the muscular tissue of the foot instead of a normal gonad.  Mature females appear to develop normal gonad tissue, and the animals are nearly always much smaller than mature males.

Studies of this most unusual situation are ongoing with the involvement of Dr. David L. Leighton, one of the countries top abalone biologists and aquaculture experts in Southern California.

Owen expressed appreciation to Matt Lum for taking several photos and recording the weights with a precision scale.  He also thanked Jack Likins, who has contributed many photographs of animals and gonad tissue to this effort.

*Independent Coast Observer (ICO), August 19, 2005.   www.mendonoma.com  :  ico@mendonoma.com

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Additional Write Up**

How Big Was That Abalone?

In last week's ICO, a photo was published with a short article relating to the huge size of a gigantic red abalone animal recently taken by Matt Lum of Santa Barbara ("largest recorded" weight by Buzz Owen in 56 years of searching for large animals of the red abalone).  However, due to preparing the article in haste, the size was not mentioned!

Here is a photo of the animal, 48 hours out of the water, placed next to a 7.75 inch shell for comparison.  Though the shell is slightly behind the animal, thus distorting the perspective somewhat, it is so close that it is touching it -- meaning the distortion is slight!

48 Hours out of the water
Photo supplied by Buzz Owen
(Click picture to enlarge)

The animal weighed 6.4 pounds at this point, over one pound heavier than the next largest recorded animal.  A photo is also included of the huge shell which measures 10.97 inches long by 9.45 inches wide, by 4.21 inches deep!  All of these measurements are extremely large, and offer a challenge to equal, much less exceed!

Photo of the Largest recorded Abalone
Photo supplied by Buzz Owen
(Click picture to enlarge)