I have been a non-active/silent member of PC for a while and this is my first post so please excuse me if I have made any errors. Just a quick introduction, my name is Mahomed Desai and I am a senior researcher and PhD candidate of the Aquatic Ecosystem Research Programme at the University of KwaZulu-Natal, South Africa. I have also been fishkeeping on and off for many years. During February and June 2017 (high-flow and low-flow seasons, respectively), I was part of a team that undertook a terrestrial and aquatic survey of a select region of the Pungwe River system within Mozambique.
Below are some of the photographs and narrative of the survey.
Pungwe River - Gorongosa District Border
The survey site located at the Gorongosa district border is the southern limit of the African Rift Valley. Below is a photograph illustrating the upstream reach of the site.
The reach was bedrock and boulder dominated and typically possessed rapid and run hydraulic biotopes.
However, during the low-flow season numerous isolated pools were also present.
The dominant siluriform species within the upper reach are illustrated below
Chiloglanis sp.
We initially thought it was but conversation with the collections manager of the South African Institute of Aquatic Biodiversity suggest that it is possibly a new species and not C. pretoriae.
Dominant non-catfish species included:
Hydrocynus vittatus
Labeo cylindricus
Cyphomyrus discorhynchus
Marcusenius macrolepidotus
The lower reach of the site was characteristically alluvium-dominated and braided.
Dominant species included:
Labeo altivelis
Brycinus imberi
Unfortunately, overfishing and unsustainable fishing practises were observed at the site with local community members using home-made gill nets and mosquito netting. However, traditional fishing practises of using traps were also observed.
Pungwe River - Gorongosa National Park
During the low-flow season we were able to sample the Pungwe River where it traverses the Gorongosa National Park. The river here inundates a relatively large floodplain and supplies water to several pans and Lake Urema during the high-flow season. During the low-flow season the river retreats and forms a braided channel with numerous backwaters and in addition, creates isolated pans within the floodplain.
Species recorded here but not at the aforementioned site included:
Microphis fluviatilis
Glossogobius giurius
The Z. monomotapia and M. fluviatilis were collected from the gravel run in the foreground in the picture below.
Furthermore, one of the temporary pans were sampled and several Protopterus annectens were collected.
In the last photo several individuals of Kassina tadpoles can be noted. These were favored prey of the lungfish.
One of the tributaries of the Pungwe River that was sampled was the Muazi River. There were several ephemeral creeks that flowed into the system during the rainy season and these distinctively provided a refuge for a diversity of biota during high flows in the Muazi. During the low-flow season the Muazi tansforms into a rapid-pool complex with a mixed boulder and bedrock substrate. Interestingly, numerous quartz crystals were embedded within the substrate (this made kick-sampling for invertebrates quite challenging). The turbidity of the water coloumn was lower than the Pungwe mainstem allowing for the extensive and relatively dense growth Hydrostachys polystachya. Based on observations and pre-liminary statistical analyses a diversity of fish species exhibited a preference for the vegetation and the rocky crevices created by the substrate as cover.
Some of the species recorded here included:
Chiloglanis sp.
Enteromius radiatus
Opsaridium zambezense
Enteromius lineomaculatus
Enteromius macrotaenia
Nothobranchius kuhntae
