Zooplankton occurrences and abundance in the Lake Kyoga system, Uganda

Study Extent

This data published in this dataset was collected from research and monitoring studies conducted in water bodies within the Lake Kyoga system. The water bodies covered are lakes Agu, Bisina, Gigatte, Kawi, Kimira, Kwania, Kyoga, Lemwa, Nawampasa and Nyaguo, and rivers Nile (Upper Victoria Nile) and Nabigagga. The studies were conducted in the period between 1998 and 2017. Data is available for specific waterbodies for 1998-2000, 2002-2004, 2006, 2009-2010, 2014-15 and 2017.

Sampling

Zooplankton samples were collected with a conical plankton net (Nansen type; mesh size 60 µm and mouth diameter of 0.25 m), towed vertically through the water column, as described by Fernando (2002) and Mwebaza-Ndawula (1994). Three hauls were taken and combined to make composite samples which preserved in 5% formalin and transferred to laboratory for taxonomic analysis and enumeration. In the laboratory, each sample was washed with tap water over a 53 µm sieve to remove the preservative and then diluted to a suitable volume, depending on the concentration of organisms in each sample. Sub-samples of 2, 2, 5 and 10 mL were taken with a wide bore automatic pipette from a well agitated sample. The sub-sample series were performed to consider more abundant organisms in 2, 2 mL series, and the rarer organisms in 2, 2, 5, 10 mL series. Each sub-sample was put into a counting chamber and examined under an inverted microscope (Hund, Wetzlar, Germany) at X100 magnification for taxonomic determination, and X40 for counting and organism body measurements.

Quality Control

Taxa were identified lowest possible taxonomic level using published taxonomic keys (Sars 1895; Pennak 1953; Brooks 1957; Rutner-Kolisko 1974; Koste 1978; Boxshall & Braide 1991; Korinek 1999). Taxonomic names were cross-checked using the World Register of Marine Species (WoRMS).Densities of organisms were calculated from counts data, with reference to the sample net mouth diameter and water column depth at each sampling site as per Fernando (2002).

Method steps

1. Collection of the zooplankton A conical plankton net (Nansen type; mesh size 60 µm; mouth diameter 0.25 m) was used to collect samples. It was towed vertically through the water column to have an integrated sample. Three hauls were taken per site and were combined to make a composite sample.
2. Preserving the samples Samples were preserved in a sugar-formalin mixture. The sugar was to stop the ballooning of cladocerans for easy identification.
3. Identification of zooplankton taxa In the laboratory, samples were washed using a sieve of 53 µm to remove the fixatives. Organisms were identified to the smallest taxonomic level possible using taxonomic keys (Sars, 1895, Pennak, 1953, Brooks, 1957, Rutner-Kolisko, 1974, Koste, 1978, Boxshall and Braide, 1991, Korinek, 1999). Density of organisms were calculated from the counts data, with reference to the sample net mouth diameter and water column depth at each sampling site.

Freshwater zooplankton identified to order, family, genus and species

1. Afrocyclops
   rank: genus
2. Ascomorpha
   rank: genus
3. Asplanchna
   rank: genus
4. Beauchampiella eudactylota
   rank: species
5. Bosmina longirostris
   rank: species
6. Brachionus angularis
   rank: species
7. Brachionus bidentatus
   rank: species
8. Brachionus budapestinensis
   rank: species
9. Brachionus calyciflorus
   rank: species
10. Brachionus caudatus
    rank: species
11. Brachionus falcatus
    rank: species
12. Brachionus forficula
    rank: species
13. Brachionus patulus
    rank: species
14. Brachionus plicatilis
    rank: species
15. Brachionus quadridentatus
    rank: species
16. Brachionus urceolaris
    rank: species
17. Brachionus variabilis
    rank: species
18. Calanoidae
    rank: family
19. Cephlodella
    rank: genus
20. Ceriodaphnia cornuta
    rank: species
21. Chydorus
    rank: genus
22. Cyclopoidae
    rank: family
23. Daphnia barbata
    rank: species
24. Daphnia lumholtzi
    rank: species
25. Diaphanosoma excisum
    rank: species
26. Euclanis
    rank: genus
27. Eucyclops
    rank: genus
28. Filinia longiseta
    rank: species
29. Filinia opoliensis
    rank: species
30. Harpacticoida
    rank: genus
31. Hexanauplia
    rank: genus
32. Hexathra
    rank: genus
33. Keratella cochlearis
    rank: species
34. Keratella tropica
    rank: species
35. Lecane
    rank: genus
36. Lecane bulla
    rank: species
37. Lecane luna
    rank: species
38. Lepadella
    rank: genus
39. Macrochaetus sericus
    rank: species
40. Macrothrix
    rank: genus
41. Mesocyclops
    rank: genus
42. Moina micrura
    rank: species
43. Platyias quadricornis
    rank: species
44. Polyarthra
    rank: genus
45. Polyarthra vulgaris
    rank: species
46. Synchaeta
    rank: genus
47. Synchaeta pectinata
    rank: species
48. Testudinella obscura
    rank: species
49. Testudinella patina
    rank: species
50. Thermocyclops
    rank: genus
51. Thermocyclops emini
    rank: species
52. Thermocyclops incisus
    rank: species
53. Thermocyclops neglectus
    rank: species
54. Thermocyclops oblongatus
    rank: species
55. Thermodiaptomus galeboides
    rank: species
56. Trichocerca
    rank: genus
57. Trichocerca cylindrica
    rank: species
58. Tropocyclops confinis
    rank: species
59. Tropocyclops tenellus
    rank: species

The dataset covers waterbodies and habitats types within the Lake Kyoga system, covering 12 water bodies (10 lakes and 2 rivers).