*Communicated by The Secretary.
Observations on the Nile Perch (Lates niloticus) in the Sudan
Article first published online: 21 AUG 2009
Proceedings of the Zoological Society of London
Volume A109, Issue 2-3, pages 157–168, July 1939
How to Cite
Kenchington, F. E. (1939), Observations on the Nile Perch (Lates niloticus) in the Sudan. Proceedings of the Zoological Society of London, A109: 157–168. doi: 10.1111/j.1096-3642.1939.tb03361.x
- Issue published online: 6 JUL 2010
- Article first published online: 21 AUG 2009
- Received March 2, 1939
- 1The damming of the Blue Nile at Sennar resulted in an increase in the numbers of Lates in the pools immediately below it. There was no trustworthy evidence of any corresponding decrease elsewhere on the river.
- 2This fish is extremely variable in form in Sudan rivers, and study by a competent taxonomist appears desirable.
- 3Sexual maturity appears to be reached at a live-weight of about 7 lb. (3.2 kg.): indications of possible habits and rhythms of spawning are noted.
- 4The spawning season at Sennar corresponds to the peak of the angling season. It lasts from December till April, with maximum in February and March.
- 5The ova are described: rough counts indicated approximately 3000 ova per gram of ovary, and 26 grams of ovary per kilo live-weight.
- 6The sexes were taken in very equal proportions throughout the season. The average weight for females exceeded that of males by nearly 9 lb. No male over 35 lb. occurred, but females of over 100 lb. were taken.
- 7The condition factor is considered for both sexes at various stages of sexual condition. A wide range of variation suggests heterogeneity in the population.
- 8The fishing season varies considerably up and down the Nile. This is thought to be due, not to a migration, but to seasonal concentrations of the local populations of Lates into limited reaches where conditions favour better oxygenation. The probable effects of climatic rhythms at Assuan, Khartoum, and Sennar upon this process are discussed in the light of the imperfect records available.