Mochokidae

Neumann, Dirk, Obermaier, Henriette & Moritz, Timo, 2016, Annotated checklist for fishes of the Main Nile Basin in the Sudan and Egypt based on recent specimen records (2006 - 2015), Cybium 40 (4), pp. 287-317 : 297

Mochokidae

With supposedly 16 taxa, mochokids are among the most specious and economically valued Nile fishes. Especially Synodontis schall (Bloch & Schneider, 1801) is landed in huge numbers and probably the most abundant catfish in terms of biomass and landed individuals. Synodontis frontosus Vaillant, 1895 and S. clarias (Linnaeus, 1758) were encountered on fish markets in Khartoum only during flood season in 2015. Synodontis khartoumensis Abu Gideiri, 1967 is close to S. schall and S. frontosus . Abu Gideiri supposed that this species could be a hybrid of schall and frontosus , but it differs in colouration (black paired fins), deeply embedded serrae on the posterior side of the dorsal spine, no serration on the distal outer and proximal inner side of the pectoral spine and a distinct granulated surface of the humeral process from S. schall and S. frontosus (see also Poll, 1971: 204- 207). The species seems to be more abundant in the White Nile and is rarely recorded from commercial catches at the type locality in Khartoum today. The occurrence of S. batensoda Rüppell, 1832 and S. membranaceus ( Geoffroy Saint-Hilaire, 1809) seems to be highly seasonal – if both species are still available in the Sudanese Nile; our record of S. batensoda dates back to the 1980s, while S. membranaceus could not be confirmed despite intensive search and several visits to fish markets during different seasons of the year. Fragments of humeral bones from excavations on Elephan- tine Island in Aswan and from lower Wadi Howar suggest that S. membranaceus was once common in landed catches and reached 400 mm TL and more. Bailey (1994) mentions S. clarias , S. serratus Rüppell, 1829 and S. sorex Günther, 1864 in his key without indicating the range inside the Nile as he did for other Synodontis (Annexe 3). Chiloglanis niloticus Boulenger, 1900 is confirmed from Taraq Island and from a single specimen at Khartoum ( Fig. 6B ). This species might be more common but surely fails to be recorded due to methodical problems, e.g. limited recovery from the riverbed. A single emaciated and likely undescribed Chiloglanis was found at the outlet canal of the Sennar Dam on the Blue Nile ( Fig. 6C ); further material is needed to evaluate the status of this population, referred to as Chiloglanis sp. “Sennar” in Annexes 2, 3.

Figures

Figure 6. – Live specimens of Chiloglanis from the Nile. A: C. niloticus, Nile River at Taraq Island, ZSM 43646 (10 Apr. 2008); B: C. niloticus, White Nile at Khartoum, ZSM 43616 (18 Jan. 2006); C: C. sp. “Sennar”, Blue Nile at Sennar, ZSM 35280 (17 Jan. 2007).