Spatial variability in fish species assemblage and community structure in four subtropical lagoons of the Okavango Delta, Botswana

Mosepele, Ketlhatlogile; Mosepele, B.; Bokhutlo, Thethela; Amutenya, K.

doi:10.1016/j.pce.2011.07.060

Cited by 8 publications

(18 citation statements)

References 14 publications

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“…Therefore, consistently poor flood years in the Delta will be dominated by C. gariepinus while predominantly good flood years will be dominated by S. intermedius [67]. Furthermore, at a large spatial scale, [71] observed spatial differences in fish community structure among several lagoons in the Delta. Generally, upper Delta lagoons have higher fish species diversity than lower Delta lagoons.…”

Section: Adult Fishmentioning

confidence: 92%

“…The Delta has a heterogeneous mosaic of micro-habitats [28] characterized by oligotrophic [36], [36], [37] waters. Despite the oligotrophic nutrient status, the Delta is a productive system [38] as evidenced by relatively high fish production/biomass in some lower Delta lagoons [39], [40] and high vegetation growth [29]. Several key processes contribute to nutrient dynamics in the Delta; (i) surface waters [36], [37], [41] (ii) soil nutrients [42], (iii) dung from mammals in the seasonal floodplains [43], (iv) mineralization (from senescent plant material and peat) [29], and (v) dust/ atmospheric deposition [42].…”

Section: Floodplain Ecology and Primary And Secondary Production Dynamentioning

confidence: 99%

See 1 more Smart Citation

Dynamics of the Seasonal Floodplain Fishery of the Okavango Delta, Botswana

Mosepele¹

2016

Environment and Water Resource Management / 837: Health Informatics / 838: Modelling and Simulation / 839: Power and Energy Sys

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Inland fisheries provide vital proteins, jobs and income, for some of the most marginalized communities of the world. Therefore, there is a compelling need to understand the dynamics of floodplain fisheries better because of their intrinsic value to riparian communities. The aim of this study is to examine the relationship between fish dynamics and environmental variability. Establishing this relationship is important towards identifying the key drivers of change, restoration and persistence in floodplain fish communities. This paper reviews literature on floodplain fish communities to highlight their dynamics and contribute to their management. This paper highlights the dynamic interactions between seasonal hydrology and nutrient dynamics in floodplain systems. These dynamic processes, coupled with a heterogeneous system, sustain a diverse fish community that is a key source of livelihoods for the riparian community. Dynamic processes within the fish community, such as distribution, feeding and growth are driven by the seasonal flood pulse. Currently, the fishery is managed through a series of classical management approaches which are incongruent with the nature of the fishery. The best management approach is through balanced harvesting, which has inadvertently been implemented by traditional exploitation practices.

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Section: Adult Fishmentioning

confidence: 92%

Section: Floodplain Ecology and Primary And Secondary Production Dynamentioning

confidence: 99%

Dynamics of the Seasonal Floodplain Fishery of the Okavango Delta, Botswana

Mosepele¹

2016

Environment and Water Resource Management / 837: Health Informatics / 838: Modelling and Simulation / 839: Power and Energy Sys

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“…A multiple linear regression was then conducted between the diet scores from axis 1 (which represents frequency of occurrence of food items) and water depth (and discharge) to explore the influence of hydrological conditions on feeding behaviour of Schilbe intermedius Rüppell, 1832 (Schilbeidae) and Marcusenius macrolepidotus (Peters, 1852) (Mormyridae). According to Mosepele et al (2011) these two species are the most dominant in the Delta's fish community. They were also the most abundant in the samples collected during this study which therefore allowed for detailed analysis.…”

Section: Methodsmentioning

confidence: 99%

Dynamics of the feeding ecology of selected fish species from the Okavango River delta, Botswana

Mosepele¹,

Mosepele²,

Wolski³

et al. 2012

Acta Icth et Piscat

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Mosepele K., Mosepele B., Wolski P., Kolding J. 2012. Dynamics of the feeding ecology of selected fish species from the Okavango River delta, Botswana. Acta Ichthyol. Piscat. 42 (4): 271-289.Background. This study contributes to the understanding of the potential impact of changes in flooding patterns and (potential) fish production as a consequence of upstream developments in floodplain systems. Therefore, stomachs of eight fish species from the Okavango Delta were analysed to evaluate the feeding ecology of floodplain fish (and the effect of seasonal flooding), using the delta as a case study. Materials and methods. In total, 2101 fish stomachs of eight species, representing six families, were collected (in all seasons) from the delta using experimental fishing nets, from 2004 to 2009. Frequency of occurrence, Levin's diet breadth index, Pianka's overlap index, trophic levels, and Bray-Curtis similarities were used to evaluate feeding preferences. Detrended correspondence analysis was used to study temporal variations in diet. Multiple linear regressions were used to determine the influence of flooding on diet. ANOVA and MANOVA were used to determine the level of significance among variables, while LSD post hoc analysis revealed the source of significance.Results. Cluster analysis and Pianka's index highlighted inter-and intra-specific competition for food among different species and age classes, ANOVA highlighted dynamic changes in inter-and intra-specific trophic level partitioning, while detrended analysis showed that the terrestrial environment is subsidizing the aquatic environment. Regression analysis showed that Schilbe intermedius diet was driven by discharge (F = 7.03; P = 0.045; R 2 = 0.58) while that of Marcusenius macrolepidotus was driven by water depth (F = 25.88; P = 0.04; R 2 = 0.93). Conclusion.The terrestrial-aquatic ecotone is important in fish growth of seasonal floodplains. Energy uptake is optimised through cannibalism to ensure species survival. Furthermore, species inter-relations are dynamic due to variations in food availability driven by seasonal flooding, which shortens and lengthens the food chain periodically. This dynamic relation is pronounced at low floods when predation and competition increases within the fish community. The evidence from this study has shown that predation, cannibalism, inter-and intra-specific competition are regulating factors in floodplain fish communities, driven by seasonal flooding.

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“…This notwithstanding, the delta's fish species have a relatively plastic feeding behavior [79,80], because of the dynamic nature of the system. Schilbe intermedius is one of the dominant species in the delta's fish community [79,81], possibly due to its opportunistic feeding ecology [79,81], where it also feeds on terrestrial food items, driven by the seasonal flood pulse [80]. Cichlids are the dominant family in the delta's fish community [81], and Mosepele [80] also found out that they have a plastic feeding behavior, where detritivorous species like Oreochromis andersonii were found to prey on fish under stressed conditions.…”

Section: Biology and Ecology Of Fisheriesmentioning

confidence: 99%

“…Similar species have different growth rates from different parts of the delta [83]. Furthermore, Mosepele et al [81] also observed habitat partitioning in fish species assemblages of the delta, where upper delta habitats have relatively higher species diversity than lower delta habitats [79]. Several studies have shown that the flood pulse is a key driver in the delta's fish community [75,80,[84][85][86].…”

Section: Biology and Ecology Of Fisheriesmentioning

confidence: 99%

Classical Fisheries Theory and Inland (Floodplain) Fisheries Management; Is there Need for a Paradigm Shift? Lessons from the Okavango Delta, Botswana

Mosepele¹

2014

Fish Aquac J

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This paper reviews the fisheries management question of inland (floodplain) systems in the developing world and proposes a paradigm shift in approach. Inland fisheries management is largely based on classical fisheries formulations derived on temperate freshwater and marine single-stock fisheries. The basic models to manage inland fisheries are based on steady state equilibrium models. However, inland, flood-pulsed fisheries are dynamic and driven by external factors which are incongruent with the classical approach. Therefore, adopting this management approach in inland, flood-pulsed fisheries has created a management conundrum because of the obvious fundamental differences that exist between these two systems. Marine fisheries contribute to the macroeconomic growth of fishing countries, inland fisheries from developing countries are largely focused on recreational activities, while inland (floodplain) fisheries are key sources of food and nutrition security for marginalized riparian communities in the developing world. This review also uses lessons from the Okavango Delta fishery to illustrate the uniqueness of floodplain fisheries and the management questions therein. One key debate highlighted in this review is that inland fisheries are a livelihood of the last resort for poor (and sometimes malnourished) communities. Management should therefore mainstream this value into management interventions, especially since a sustainable utilization of this resource can assist developing countries to achieve some of the MDG's. The paper concludes with an argument of the need for a paradigm shift in inland fisheries management, where key factors such as enhanced data collection, co-management regimes based on "real" democratic principles constitute some of the germane attributes of fisheries management plans.

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Spatial variability in fish species assemblage and community structure in four subtropical lagoons of the Okavango Delta, Botswana

Cited by 8 publications

References 14 publications

Dynamics of the Seasonal Floodplain Fishery of the Okavango Delta, Botswana

Dynamics of the Seasonal Floodplain Fishery of the Okavango Delta, Botswana

Dynamics of the feeding ecology of selected fish species from the Okavango River delta, Botswana

Classical Fisheries Theory and Inland (Floodplain) Fisheries Management; Is there Need for a Paradigm Shift? Lessons from the Okavango Delta, Botswana

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