05 May 2010

Eastern Cape Rocky


Dr Jim Cambray is a Curator of Ichthyology at the Makana Biodiversity Centre , Albany Museum. In this blog Dr Cambray sheds some unknown facts about the Eastern Cape Rocky.
The Eastern Cape Rocky is an endangered freshwater fish species which only occurs in the Eastern Cape. The scientific name is Sandelia bainsii and it belongs in the family of fishes called Anabantidae. It is a medium size fish and reaches a lenght of about 30 cm. It has a narrow distribution and only occurs in small sections of the following river systems , Nahoon , Buffalo , Gulu , Igoda, Kesikamma , Great Fish and Kowie.
The scientific name of the Eastern Cape Rocky , Sandelia bainsii has a very interesting history.
Chief Sandile ( 1820-1878)
The generic name of the Eastern Cape Rocky is Sandelia. This is very interesting as the fish was named after Chief sandile who was born in 1820 near Burnshill in the Eastern Cape. He was the son of Ngqika the paramount Chief of the Rharhabe. sandile acceded to the chieftainship in 1840. He was the central figure in 'War of the Axe' between 1846-1847 and was killed in action in last Frontier war ( 1877-1878).
Andrew Geddes Bain (1797-1864)
The species name of the Eastern Cape Rocky is bainsii. Some people have thought this name is derived from Thomas Baines the painter but it is in fact named after Andrew Geddes Bain. He was born in Scotland in 1797 , arrived in South Africa in 1816 and he became famous for his many talents. He was a road-builder , geologist , explrer , trader , soldier , writer and artist. he was to become known as the father of South African geology. in 1838 he made his first important fossil discovery , and several days later made his important discovery of the dicynodon.
How does the Eastern Cape Rocky breed?
Research at the Albany Museum has shown that these fish are not free spawners as once thought. The males and females in free spawning fishes quickly mate and then leave the eggs to the mercy of the environment.
Studies have now shown that during the spawning season , October to February , the males turn a very dark colour and the larger ones have whitish tips on someof their fins. This is called a breeding dress or plumage. Not only birds have a breeding plumage so do some fish!
The males guard a territory and prepare a clean ara for eggs. The male occassionally leaves his territory and goes to the surface to take a big gulp of air. This he stores in his special superbranchial air chambers which are located in his head. He then goes up to female and lets out some air bubbles as he approaches her and then quickly turns inviting the female back to the cleared area he has made.
The female enters the area above the cleared nest and then remains almost motionless suspended in the water column. The male then slowly wraps around her and then quickly squezees and jabs the special sharp and pointed scales on his head, called contact organs, into the female abdomen. The female releases hundreds of eggs and the male milt. The fertilised eggs sink and adhere to the clean substrate teh male has prepared.
The female then leaves the area while the male goes into a 'headstand' position and carefully examiness the eggs. When the male finishes this inspection he will again go to the surface refresh his air supply and blow bubbles at the female and the spawning sequence will be repeated.
After the spawning is completed the male would not let any fish near his nest. Thus it was determined that the Eastern Cape Rocky is not a free spawner but a male guarder which is important in understanding its relationships with other African anabatids.
A study on the early development of this species also revealed a number of interesting and unique characters. There is a display and a live specimen of the Eastern cape Rocky in the Blue Planet gallery at the Albany Museum.
So next time you are at the museum learn more about this very unique Eastern Cape species with the interesting scientific name , Sandelia bainsii. Help conserve it by not introducing any alien fish species , such as bass or catfish, into its home range.

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