Fish species distribution, with emphasis on haplochromine cichlids, in different habitats of the Ugandan portion of Lake Victoria DataSet Details

Description:

This dataset constitutes haplochromine cichlids, and other few fish taxa, from diverse habitats (rocky, muddy, vegetated, sandy, open water, aquaculture sites) in the northern portion of Lake Victoria (Uganda) observed through a combination of gillnet and bottom trawl surveys.

Purpose:

The objective of the survey was to determine the distribution and relative abundance of fish, with major emphasis on haplochromine cichlids, as influenced by habitat and external drivers such as cage aquaculture.

This project was funded by a National Science Foundation (NSF) grant to the University of Denver and the Lake Victoria Fisheries Organization (LVFO).

Temporal scope:

2017

Taxonomic scope:

Orders: 8
Families: 12
Genera: 37
Species: 56

Methodology:

Study extent
The study covered parts of the Northern Lake Victoria, Uganda, between April and August 2017.

Sampling
Bottom trawling and gillnetting were carried out at selected stations, with varying habitat characteristics, in 2017 using the research vessel R.V. Hammerkop and graded monofilament/multifilament nets, respectively. For the bottom trawling, hauls of 30 minutes duration were taken using a 25.4 mm cod-end stretched mesh trawl net in the various grids (see LVFO 2007 for standard operating procedures), towed at 3.4 knots. For gillnetting, two fleets of graded monofilament gillnets of mesh size 0.75”, 1.00”, 1.25”, 1.50” and 2.00” were soaked and retrieved at 30 minute to two hour intervals. On retrieval, fish were removed according to mesh size, separated into labelled buckets filled with water and transported back to the shore or research vessel (for the trawl survey) for further processing.

At the shore or aboard the research vessel, identical fish species in each bucket were lumped together. Photographs of live specimens were taken using a digital camera. The left side of each live fish was photographed inside a photo cuvette that had a colour bar and label attached to its background using masking tape and was filled with water (up to ¾ of total volume). The rare and unique species were photographed first before the other specimens in the rest of the catch. After taking the photographs, the fish specimens were euthanized using a solution of MS-222 or clove oil, tagged, and fin clips and tissue samples obtained for genetics and stable isotopes respectively. For DNA samples, fin clips were obtained from the right pectoral fin of individuals of unidentified fish species and placed into plastic vials filled with 99% ethanol solution, and sent to Switzerland (Eawag) for full genome sequencing and further identification. Fish species that could not be identified to species level were given cheironyms.

Method steps
Photos were taken to facilitate identification of fish specimens, and identification of fish was done by an expert (Ole Seehausen) with over 30 years’ experience in taxonomy of Lake Victoria fishes, especially haplochromine cichlids .

Bibliography:

Number of Occurrencies:

447 Records

Authors:

Vianny Natugonza

Laban Musinguzi

Monic Nsega

Samuel Bassa

Richard Mangeni-Sande

WInnie Nkalubo

Philip Rwezawula