Is the Invasion of Water Hyacinth, Eichhornia Crassipes Solms (Mart.), a Blessing to Lake Victoria Fisheries?

Njiru, M.; Othina, A.; Getabu, Albert; Tweddle, Denis; Cowx, I. G.

doi:10.1002/9780470995679.ch21

Cited by 35 publications

(55 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The advantage of Nile perch occupying wetland ectones was probably to maximize prey capture, and seek refuge from cannibalism and intense fishing. Although intense fishing pressure on Nile perch coincided with faunal resurgence in Lake Victoria, it is possible that other environmental changes have contributed to the observed patterns (Njiru et al, 2002). The resurgence in native species in the early 2000s coincided with the lake invasion by water hyacinth.…”

Section: Wetlands and Rocky Habitatsmentioning

confidence: 99%

“…Shading of the water by the hyacinth curtailed photosynthesis, while microbial breakdown of decaying plant material used the available oxygen. The waters below water hyacinth recorded DO as low as 0.1 mgl -1 making it inhabitable to most fish (Njiru et al, 2002). Additionally, the weed affected distribution of fish by blocking migratory routes of those escaping low DO and predation (Balirwa et al, 2003).…”

Section: Anoxia 106mentioning

confidence: 99%

“…Additionally, the weed affected distribution of fish by blocking migratory routes of those escaping low DO and predation (Balirwa et al, 2003). However, studies by Njiru et al, (2002) found the hyacinth to have led to recovery of the native species which where more hypoxia tolerant such as catfishes, lungfish and tilapia (Figure 4). …”

Section: Anoxia 106mentioning

confidence: 99%

“…The weed invasion had significant socioeconomic and environmental impacts and affected water quality (Twongo et al, 1995;Njiru et al, 2002). Shading of the water by the hyacinth curtailed photosynthesis, while microbial breakdown of decaying plant material used the available oxygen.…”

Section: Anoxia 106mentioning

confidence: 99%

See 3 more Smart Citations

Increase in Anoxia in Lake Victoria and Its Effects on the Fishery

Njiru¹,

Nyamweya²,

Gichuki³

et al. 2012

Anoxia

View full text Add to dashboard Cite

Section: Wetlands and Rocky Habitatsmentioning

confidence: 99%

Section: Anoxia 106mentioning

confidence: 99%

Section: Anoxia 106mentioning

confidence: 99%

Section: Anoxia 106mentioning

confidence: 99%

See 2 more Smart Citations

Increase in Anoxia in Lake Victoria and Its Effects on the Fishery

Njiru¹,

Nyamweya²,

Gichuki³

et al. 2012

Anoxia

View full text Add to dashboard Cite

“…The hyacinth invasion was in large part managed between 1997 and 1999 through manual removal and the introduction of a weevil (Neochetina eichhorniae). The effects of these management procedures were probably enhanced by an El Niño episode (1997)(1998), during which elevated water levels broke off large hyacinth stands, and where low light conditions (clouds) and rain reduced hyacinth growth (Njiru et al 2002, Williams et al 2005, Wilson et al 2007. Even though the hyacinth bloom was probably triggered by eutrophication, its decline is not a reaction to improved water quality: there are multiple pathways to any single phenomenon.…”

Section: Introduced Species Changed Ecosystemmentioning

confidence: 99%

Coupled human and natural system dynamics as key to the sustainability of Lake Victoria’s ecosystem services

Downing¹,

Nes²,

Balirwa³

et al. 2014

E&S

View full text Add to dashboard Cite

ABSTRACT. East Africa's Lake Victoria provides resources and services to millions of people on the lake's shores and abroad. In particular, the lake's fisheries are an important source of protein, employment, and international economic connections for the whole region. Nonetheless, stock dynamics are poorly understood and currently unpredictable. Furthermore, fishery dynamics are intricately connected to other supporting services of the lake as well as to lakeshore societies and economies. Much research has been carried out piecemeal on different aspects of Lake Victoria's system; e.g., societies, biodiversity, fisheries, and eutrophication. However, to disentangle drivers and dynamics of change in this complex system, we need to put these pieces together and analyze the system as a whole. We did so by first building a qualitative model of the lake's social-ecological system. We then investigated the model system through a qualitative loop analysis, and finally examined effects of changes on the system state and structure. The model and its contextual analysis allowed us to investigate system-wide chain reactions resulting from disturbances. Importantly, we built a tool that can be used to analyze the cascading effects of management options and establish the requirements for their success. We found that high connectedness of the system at the exploitation level, through fisheries having multiple target stocks, can increase the stocks' vulnerability to exploitation but reduce society's vulnerability to variability in individual stocks. We describe how there are multiple pathways to any change in the system, which makes it difficult to identify the root cause of changes but also broadens the management toolkit. Also, we illustrate how nutrient enrichment is not a self-regulating process, and that explicit management is necessary to halt or reverse eutrophication. This model is simple and usable to assess system-wide effects of management policies, and can serve as a paving stone for future quantitative analyses of system dynamics at local scales.

show abstract

Threats to aquatic biodiversity and possible management strategies in Lake Victoria

Muthoka,

Ogello,

Outa

et al. 2023

Aquaculture Fish & Fisheries

View full text Add to dashboard Cite

Lake Victoria is the second‐largest freshwater lake in the world, with a surface area of 68,800 km2. The lake is rich in natural resources that are essential to the local economy and livelihoods. However, International Union for Conservation of Nature (IUCN) ranks 76% of freshwater species endemic to the Lake Victoria Basin as threatened with extinction. The biodiversity richness of the lake is still diminishing, and the risk of species extinction is increasing. Many species are yet to be identified, and thus the number of species threatened with extinction exceeds what is currently known. Furthermore, the lake is home to species that are found nowhere else on the planet, but its protection is never given the attention it needs. Genetic diversity loss is harmful to future populations and influences sustainability of the ecosystem. The decline in Lake Victoria's biodiversity is primarily attributed to various pressing issues, including water pollution, invasive species, climate change, overexploitation and the challenges stemming from high human population density. These problems are exacerbated by inadequate regulatory enforcement and a lack of comprehensive data and information to inform and guide conservation efforts. If these factors are not addressed, they may have a detrimental impact on Lake Biodiversity. This article aims to document the main threats to aquatic biodiversity as well as potential management strategies for preventing further losses of the aquatic biodiversity in Lake Victoria. The study recommends reviewing, bolstering and reinforcing the rules and regulations governing the extraction, accessibility and discharge of nutrients into the lake. The national governments should work with local governments, non‐governmental organizations and local people to safeguard and conserve the lake's biodiversity. The national governments of the riparian nations should also reserve funds each fiscal year specifically for research that would inform effective management measures to prevent further losses of the lake's biodiversity.

show abstract

Is the Invasion of Water Hyacinth, Eichhornia Crassipes Solms (Mart.), a Blessing to Lake Victoria Fisheries?

Cited by 35 publications

References 2 publications

Increase in Anoxia in Lake Victoria and Its Effects on the Fishery

Increase in Anoxia in Lake Victoria and Its Effects on the Fishery

Coupled human and natural system dynamics as key to the sustainability of Lake Victoria’s ecosystem services

Threats to aquatic biodiversity and possible management strategies in Lake Victoria

Contact Info

Product

Resources

About

Is the Invasion of Water Hyacinth, Eichhornia Crassipes Solms (Mart.), a Blessing to Lake Victoria Fisheries?

Cited by 35 publications

References 2 publications

Increase in Anoxia in Lake Victoria and Its Effects on the Fishery

Increase in Anoxia in Lake Victoria and Its Effects on the Fishery

Coupled human and natural system dynamics as key to the sustainability of Lake Victoria&#8217;s ecosystem services

Threats to aquatic biodiversity and possible management strategies in Lake Victoria

Contact Info

Product

Resources

About

Coupled human and natural system dynamics as key to the sustainability of Lake Victoria’s ecosystem services