Spatial and temporal variation in the distribution and density of pelagic fish species in Lake Victoria, East Africa

Anthony Taabu-Munyaho; Chrisphine S. Nyamweya; Lewis Sitoki; Robert Kayanda; Inigo Everson; Gudrún Marteinsdóttir

doi:10.1080/14634988.2014.876886

Spatial and temporal variation in the distribution and density of pelagic fish species in Lake Victoria, East Africa

Anthony Taabu-Munyaho^*, Chrisphine S. Nyamweya, Lewis Sitoki, Robert Kayanda, Inigo Everson, Gudrún Marteinsdóttir

^*Corresponding author for this work

Faculty of Life and Environmental Sciences

Research output: Contribution to journal › Article › peer-review

16 Citations (Scopus)

Abstract

The distribution and densities of three pelagic fish taxa (Nile Perch, Lates niloticus, Rastrineobola argentea [Dagaa], and the haplochromine cichlids) in Lake Victoria were estimated through 17 lake-wide acoustic surveys conducted in two series (August 1999-August 2002 and August 2005-September 2011). Nile Perch densities were estimated through echo-counting, while Dagaa and haplochromines by echo-integration. Mixed generalized linear model estimates indicated up to 30% decline in Nile Perch densities in the deep and coastal areas and up to 65% reduction in the shallow inshore areas over the study period. There was a twofold increase in Dagaa densities and a 10% increase in haplochromines. The distribution and densities of these species were influenced by season, stratum and year of survey. In addition to fish exhibiting seasonal clustering in the upper layers of the water column, they also appeared to spread to shallow inshore waters. The Nyanza, Speke, and Emin Pasha Gulfs demonstrated diverse spatial stock oscillations in abundance, and distribution which call for a need to include area disaggregated considerations in stochastic models when predicting dynamics of fish stocks.

Original language	English
Pages (from-to)	52-61
Number of pages	10
Journal	Aquatic Ecosystem Health and Management
Volume	17
Issue number	1
DOIs	https://doi.org/10.1080/14634988.2014.876886
Publication status	Published - Jan 2014

Bibliographical note

Funding Information:
We thank the skipper and crew of the RV Victoria Explorer, scientists and technicians and all international technical assistants (consultants) who participated in data collection during LVFRP II and IFMP. Funds for the surveys were provided through the EU funded LVFRP II and IFMP projects. The reanalysis of survey data that has resulted in production of this paper was provided through a fellowship provided by the United Nations University Fisheries Training Program (UNU-FTP). Participation of two of the authors in the Great Lakes of the World (GLOW) conference was provided by the Lake Tanganyika Authority (LTA) and the Faculty of Life and Environmental Sciences, University of Iceland. This article has benefited from comments provided by Professor Brian Marshall and Dr. Richard Ogutu-Ohwayo.

Other keywords

acoustic surveys
biomass
Dagaa
echo-counting
echo-integration
Haplochromines
Nile Perch

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10.1080/14634988.2014.876886

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title = "Spatial and temporal variation in the distribution and density of pelagic fish species in Lake Victoria, East Africa",

abstract = "The distribution and densities of three pelagic fish taxa (Nile Perch, Lates niloticus, Rastrineobola argentea [Dagaa], and the haplochromine cichlids) in Lake Victoria were estimated through 17 lake-wide acoustic surveys conducted in two series (August 1999-August 2002 and August 2005-September 2011). Nile Perch densities were estimated through echo-counting, while Dagaa and haplochromines by echo-integration. Mixed generalized linear model estimates indicated up to 30% decline in Nile Perch densities in the deep and coastal areas and up to 65% reduction in the shallow inshore areas over the study period. There was a twofold increase in Dagaa densities and a 10% increase in haplochromines. The distribution and densities of these species were influenced by season, stratum and year of survey. In addition to fish exhibiting seasonal clustering in the upper layers of the water column, they also appeared to spread to shallow inshore waters. The Nyanza, Speke, and Emin Pasha Gulfs demonstrated diverse spatial stock oscillations in abundance, and distribution which call for a need to include area disaggregated considerations in stochastic models when predicting dynamics of fish stocks.",

keywords = "acoustic surveys, biomass, Dagaa, echo-counting, echo-integration, Haplochromines, Nile Perch",

author = "Anthony Taabu-Munyaho and Nyamweya, {Chrisphine S.} and Lewis Sitoki and Robert Kayanda and Inigo Everson and Gudr{\'u}n Marteinsd{\'o}ttir",

note = "Funding Information: We thank the skipper and crew of the RV Victoria Explorer, scientists and technicians and all international technical assistants (consultants) who participated in data collection during LVFRP II and IFMP. Funds for the surveys were provided through the EU funded LVFRP II and IFMP projects. The reanalysis of survey data that has resulted in production of this paper was provided through a fellowship provided by the United Nations University Fisheries Training Program (UNU-FTP). Participation of two of the authors in the Great Lakes of the World (GLOW) conference was provided by the Lake Tanganyika Authority (LTA) and the Faculty of Life and Environmental Sciences, University of Iceland. This article has benefited from comments provided by Professor Brian Marshall and Dr. Richard Ogutu-Ohwayo.",

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AU - Kayanda, Robert

AU - Everson, Inigo

AU - Marteinsdóttir, Gudrún

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ER -

Spatial and temporal variation in the distribution and density of pelagic fish species in Lake Victoria, East Africa

Abstract

Bibliographical note

Other keywords

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