Benthic macroinvertebrate taxa occurrences and composition associated with a cage aquaculture farm on Lake Victoria, Uganda

Study Extent

The monitoring project commenced in 2011. In that year, sampling was conducted once in February, May, September and November at each of the selected sampling points in each transect.

Sampling

A Ponar grab (with open jaw area, 238cm2) was used to take sediment samples for analysis of benthic macroinvertebrates. Three spread hauls were taken from each of the selected areas (see design above). The bottom type at each point was described from the grabbed contents. Each of the three samples (hauls) from each area was then concentrated placed in labeled sample bottles, and preserved with 5% formalin solution and taken for laboratory analysis. In the laboratory, each sample was rinsed with water to remove the formalin and then placed on a white flat-bottomed tray. Using pair of forceps all macro-invertebrates were sorted from the sediment and the individual taxa identified to the lowest possible taxonomic level using identification manuals and a dissecting binocular microscope at x 25 magnification. All taxa from the different hauls were recorded and individuals of each taxon enumerated to estimate their densities from which the following results were generated. The taxa were identified using taxonomic keys by Mandahl-Barth (1954), Pennak (1953), and Merritt and Cummins (1997).

Quality Control

The samples were immediately processed in the field and treated with formalin to keep the organisms of interest intact and prevent them from rotting. To avoid loss of organisms during sample processing, appropriate mesh sizes were used.

Method steps

1. Collection of the macroinvertebrates In the field, sediment samples were collected using a ponar grab with an open jaw surface area of 238 cm2. At each site, three sediment samples were obtained. The three samples were mixed and concentrated to form one composite sample for each site.
2. Preserving the samples The composite sample for each site was separately preserved in 5% formalin to maintain the organisms in good condition prior to analysis in the laboratory.
3. Identification of macroinvertebrates In the laboratory, formalin was rinsed off from each sample and placed in white flat-bottomed trays. Using pairs of forceps, all benthic macro invertebrates were sorted from the sediment and the individual taxa identified to the lowest possible taxonomic level using appropriate identification keys and a dissecting binocular microscope at x 25 magnification.

This information is about the benthic macro-invertebrates (ie; invertebrates which live on or in the sediment at the bottom of the water bodies and are big enough to be seen with naked eyes).

1. Ablabesmyia
   rank: genus
2. Anisus natalensis
   rank: species
3. Aspatheria
   rank: genus
4. Baetidae
   rank: family
5. Bellamya unicolor
   rank: species
6. Biomphalaria
   rank: genus
7. Bulinus
   rank: genus
8. Byssanodonta parasitica
   rank: species
9. Caelatura alluaudi
   rank: species
10. Caelatura hauttecoeuri
    rank: species
11. Caelatura monceti
    rank: species
12. Caenis
    rank: genus
13. Caridina nilotica
    rank: species
14. Ceratopogonidea
    rank: family
15. Chaoborus
    rank: genus
16. Chironomidae
    rank: family
17. Chironominea
    rank: subfamily
18. Chironomus
    rank: genus
19. Cleopatra pirothi
    rank: species
20. Clinotanypus
    rank: genus
21. Corbicula africana
    rank: species
22. Cryptochironomus
    rank: genus
23. Dipsuedopsis
    rank: genus
24. Economus
    rank: genus
25. Ephemerella
    rank: genus
26. Etheria eliptica
    rank: species
27. Euthraulus
    rank: genus
28. Gabbia humerosa
    rank: species
29. Heptageniidae
    rank: family
30. Hirudinea
    rank: class
31. Ictinogomphus
    rank: genus
32. Lentorbis junodi
    rank: species
33. Leptoceridae
    rank: family
34. Libellulidae
    rank: family
35. Melanoides tuberculata
    rank: species
36. Mutela bourguignati
    rank: species
37. Oligochaeta
    rank: class
38. Perlidae
    rank: family
39. Phyllomacomia
    rank: genus
40. Pila ovata
    rank: species
41. Pisidium victoriae
    rank: species
42. Povilla adusta
    rank: species
43. Procladius
    rank: genus
44. Pseudoneureclipsis
    rank: genus
45. Sphaerium
    rank: genus
46. Tanypus
    rank: genus
47. Tanytarsus
    rank: genus
48. Terithemis
    rank: genus
49. Tricorythus
    rank: genus

The geographical area covers the location of the cage fish farm where data was collected.