By Elson T. Elizaga
 
 
II. BEHAVIOR
 

THE FIRST MEGAMOUTH WAS CAUGHT IN 1976 by the US Navy in Oahu, Hawaii and after that only 10* others have been recorded found. The last recorded sighting -- prior to the discovery in the Philippines -- was on May 1997 in Toba, Japan. Photos of the shark are also rare and usually show a dead specimen, but underwater photographer Tom Haight has shots of one alive. 

 

Megamouth 9
Megamouth 9 in Brazil

 

Little is known about the megamouth, but according to Lee Krystek in his Gallery of Cryptozoological Alumni (1996), "This extremely rare shark is harmless to humans. Its huge mouth is full of tiny teeth which are used to filter the water as the animal sucks in tiny shrimp and plankton that make up its diet. Two other members of the shark family, the basking shark and the whale shark, use the same feeding technique." 

A 1996 reference made by Melissa Kim of the University of Michigan contains a description of megamouth movement: "This shark behaves similarly to the fish of the deep scattering layer. It migrates vertically during a twenty-four hour cycle, swimming at depths of 200 meters below the surface by day, and ascending to 10-15 meters below the surface by night. It flees from minute disturbance into deep depths, which may explain why this species remained undiscovered for so long." 

III. SEARCH

A MYSTERIOUS FACT ABOUT THE MEGAMOUTH is that, according to the distribution table prepared by Morrissey, five of the first six megamouths found were males, the other being of unknown gender because it was discarded. So when the first female megamouth was discovered in 1994 in Fukuoka, Japan, an excited international team of scientists examined the carcass, resulting in the publication of "Biology of the Megamouth Shark". 

Despite this document and several research papers, interest in finding another female megamouth remains very high. Most shark experts consulted by this writer requested to be informed about the gender of the Philippine megamouth. When this writer asked Kazuhiro Nakaya, an Associate Professor of the Faculty of Fisheries of Hokkaido University, he explained: 

"One of our great interests is to discover an embryo in the uterus of the megamouth. But we have not found any in the two females. So, very little of the reproductive organs is known, and nothing is known about the reproductive biology of the megamouth shark ... If you find the female, you should keep the specimen. If not, keep the whole internal organs. You can throw the liver away, because of its enormous size, but keep the rest of the internal organs. Please bear this [advice] in mind, and watch for another megamouth. I will be happy to help you in this matter or with regards to other sharks in the Philippines."

Nakaya is also one of the editors of "Biology of the Megamouth Shark".  

How to identify the gender? "The male megamouth," according to Nakaya, "has a pair of claspers on inner side of pelvic fin, but the female has no clasper." George H. Burgess describes the claspers as "large modifications of the pelvic fins used as intromittent organs during copulation." He writes that these are all found on all male sharks. Burgess is the Director of the International Shark Attack File, Florida Museum of Natural History, University of Florida. 

 

Megamouth 4
Male megamouth 4 showing claspers. Middle large mass is part of intestine pushed out.

 

In response to the request of this writer, Nakaya sent photos of a male and female megamouths. A photo of a male megamouth was shown to the fishermen in May, with the explanation that claspers are absent in females. The fishermen said they saw the same pair of prominent claspers on megamouth 11.   

* Thirty-four megamouths have been found worldwide as of January 2006. | See also Megamouth fossil records. Check out John F. Morrissey and Elson T. Elizaga, "Capture of Megamouth 11 in the Philippines", The Philippine Scientist (San Carlos Publications, University of the Philippines, Cebu City, Philippines), vol. 36, 1999. Webpage issued on March 18, 1998. Updated January 29, 2006. |
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