Wednesday, Sept. 27, 2006
* Japanese name: Gigi
* Scientific name: Pelteobagrus nudiceps
* Description: This is a rather small, 10- to 15-cm-long bottom-dwelling river fish that is remarkable for being one of the few aquatic organisms to have a voice. Fishermen report that when a gigi catfish is landed, it emits a "giiii-giiii" noise -- hence the name. The fish's fins -- the dorsal, two ventral, pelvic and pectoral -- are well developed and the caudal (tail) fin is deeply forked. With all those fins, the fish is able to accurately control its position in a fast-flowing river by continually adjusting the flow rate of water around its body. It has several long barbels (the sensory "whiskers" that give catfish their name) around the mouth. Catfish don't have scales, and the body ranges from an almost translucent gray to a stony, moss-colored green. They live for four to five years.
* Where to find them: In Honshu and Kyushu, around rocks at the bottom of rivers. It is mainly fishermen who know about gigi catfish, as they are difficult to spot among a riverbed's dark rocks.
* Food: Small crustaceans and insect larvae, small fish and tadpoles. Gigi catfish can hunt in the murky water at the bottom of the river, using their motion-detecting barbels to locate prey.
* Special features: In northeast Asia there are about 20 species of catfish in the same genus, Pelteobagrus, as the gigi. Most, including the gigi, are sexually dimorphic. Males "let it all hang out" -- they are unusual among fish in possessing external genital organs, in this case palps (they don't have a penis). Females can sometimes be easily identified as, if they are carrying eggs, they will be clearly visible through the transparent body walls. The eggs are a blue-green color. The male constructs a rocky nest for the female, into which she lays her eggs. Both parents guard the eggs for the first few weeks as they develop. Research indicates that a substance derived from the oil of the gigi catfish has immune-system-boosting properties. It has been investigated as a treatment for tuberculosis patients, as the oil is supposed to promote the healing of lung damage caused by the disease.
PHOTO COURTESY OF BIO-IMAGE NET