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18 results on '"Tatenda Dalu"'

1. Using self–organizing maps and machine learning models to assess mollusc community structure in relation to physicochemical variables in a West Africa river–estuary system

Author

Zinsou Cosme Koudenoukpo, Olaniran Hamed Odountan, Prudenciène Ablawa Agboho, Tatenda Dalu, Bert Van Bocxlaer, Luc Janssens de Bistoven, Antoine Chikou, and Thierry Backeljau

Subjects
Artificial neural network, Ecology, Freshwater biodiversity, Modelling, Mollusc community, Tropical river systems, QH540-549.5
Abstract

The poor understanding of changes in mollusc ecology along rivers, especially in West Africa, hampers the implementation of management measures. We used a self–organizing map, indicator species analysis, linear discriminant analysis and a random forest model to distinguish mollusc assemblages, to determine the ecological preferences of individual mollusc species and to associate major physicochemical variables with mollusc assemblages and occurrences in the Sô River Basin, Benin. We identified four mollusc assemblages along an upstream–downstream gradient. Dissolved oxygen (DO), biochemical oxygen demand (BOD), salinity, calcium (Ca), total nitrogen (TN), copper (Cu), lead (Pb), nickel (Ni), cadmium (Cd) and mercury (Hg) were the major physicochemical variables responsible for structuring these mollusc assemblages. However, the physicochemical factors responsible for shaping the distribution of individual species varied per species. Upstream sites (assemblage I) showed high DO and low BOD and mineral compounds (i.e., TN, salinity, and Ca), which are primarily responsible for structuring the occurrences of bivalves (Afropisidium pirothi, Etheria elliptica, Sphaerium hartmanni) and the gastropod Lanistes varicus. Sites along the middle reach (assemblage II) were characterised by a high degree of organic pollution but low heavy metal pollution; we detected no specific mollusc indicator species. Downstream sites (assemblage III) displayed high mineral and heavy metal concentrations and a fauna without specific indicator species. Finally, downstream sites associated with brackish water (assemblage IV) displayed important levels of organic and heavy metal pollution. These sites are dominated by diverse gastropods (i.e., Bulinus spp., Gabbiella africana, Indoplanorbis exustus, Pachymelania fusca, Radix natalensis, Stenophysa marmorata and Tympanotonos fuscatus). Our results highlight that mollusc communities in the Sô River Basin are structured by key physicochemical variables related to the river–estuary continuum. Habitats that are progressively more downstream are confronted with increasing anthropogenic stress. Conservation and management plans should focus on downstream habitats.

Published
2021
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2. Challenges and possible impacts of artisanal and recreational fisheries on tigerfish Hydrocynus vittatus Castelnau 1861 populations in Lake Kariba, Zimbabwe

Author

Terence Magqina, Tamuka Nhiwatiwa, Mwazvita T.B. Dalu, Lindah Mhlanga, and Tatenda Dalu

Subjects
Lake Kariba, Tigerfish, Breeding season, Fishing tournament, Hydrocynus vittatus, Socioeconomic factors, Science
Abstract

Increased fishing pressure from artisanal and recreational fishing has led to the collapse of some important fish stocks around the world over the past years. There is currently limited understanding of the impacts of recreational and artisanal fishing on tigerfish Hydrocynus vittatus populations in Lake Kariba and the socioeconomic factors behind them. Hence, this study investigated socioeconomic factors that act as drivers of the recreational and artisanal fishery industry and what sort of impact this would likely have on tigerfish H. vittatus populations using qualitative approaches. Eight three percent of the artisanal fishers interviewed recorded high catches during the summer season (October–February), which also coincides with the breeding season for tigerfish when it migrates up the rivers. Recreational anglers mainly caught females during the tigerfish tournament which is likely to have a significant effect on the tigerfish population in the long term through changes in tigerfish recruitment and other life history traits. Tigerfish size at sexual maturity and catch per unit effort which are all indicators of overexploitation were found to have decreased over the past years. Results further demonstrated increased fishing activities from artisanal and recreational fishing. It can be implied that the population of tigerfish may inadvertently be affected, but direct evidence that both recreational and artisanal fishing were having impacts on tigerfish populations was limited. It is therefore recommended that effective conservation measures such as preventing fish poaching during the tigerfish breeding season are put in place to protect the population and that of other fishes (i.e. potential prey).

Published
2020
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4. Contributors

Author

R. Fanelwa Ajayi, Rana Al-Jaibachi, Simone Barry, Taurai Bere, Amanda Callaghan, Adroit T. Chakandinakira, Luke Chimuka, Joseph Clokey, Joyce Cristale, Ygor J.A.B. da Silva, Yuri J.A.B. da Silva, Tatenda Dalu, Jéssyca Ferreira de Medeiros, Eder de Vilhena Araújo, Simiso Dube, Juliana A. Galhardi, Sara G. Gorji, Leandro W. Hantao, Sayyed H. Hashemi, Darryl W. Hawker, Tatenda A. Kajau, Sarit L. Kaserzon, Massoud Kaykhaii, Temesgen G. Kebede, Sinegugu Khulu, Isaac Kudu, Ramesh B. Kumar, Karen Luko-Sulato, Lawrence M. Madikizela, Tinotenda Mangadze, Geaneth P. Mashile, Cassiana C. Montagner, Brenda Moodley, Babra Moyo, Anele Mpupa, Takalani Muluadzi, Nívea C.G. Munin, Herbert Musarurwa, Tongayi Mwedzi, Somandla Ncube, Nzumbululo Ndou, Sol S. Nety, Nokwanda Ngema, Mathew M. Nindi, Mulisa Nkuna, Azile Nqombolo, Philiswa N. Nomngongo, Sphamandla Nqunqa, Gershom M. Ntshani, Srinivas Oruganti, Vishalan Pillay, Tessia Rakgotho, Cornelius Rimayi, Edmond Sanganyado, Leandro M. Santos, Shirley K. Selahle, Saikat Sen, Nikita T. Tavengwa, Velaphi Thipe, Rahul K. Varma, Rory Verhagen, B.C. Vizioli, Lauren N.M. Yabuki, and Lewis D. Yardy

Published
2022

5. List of contributors

Author

Radwan G. Abd Ellah, Eman I. Abdel-Aal, Adel Ali Ahmed Abdelmageed, Asmaa M. Abdeltwab, Hamdy A. Abo-Taleb, Gloria Addico, Magdi M. Ali, Samar Sami AlKafaas, Mohamed S. Amer, Heléne Annadotter, Wilgince Apollon, Christopher Mulanda Aura, Khouloud M. Barakat, Heba Bedair, Chadwick Henry Bironga, Charné Bornman, Tatenda Dalu, Timothy Dube, Manal I. El Barbary, Waleed M.M. El Sayed, Rehab Mohamed Abo Elfadl, Sara Samy Elkafas, Noha Ahmed El-Sebaii, Mostafa El-Sheekh, Mohamed A. El-Tabakh, Doha Mohamed Fathy, Ahmed A. Gad, Samiha M. Gharib, Soumya Ghosh, Ghada E. Hegazy, Dina M. Hendy, Hassan A.H. Ibrahim, Gaurav Kant, Hanan M. Khairy, Takudzwa C. Madzivanzira, Abeer Mohamed Ahmed Mahmoud, John Odoyo Malala, Noha M. Mesbah, Lindah Mhlanga, Chipo P. Mungenge, Safina Musa, Aidate Mussagy, Romano Mwirichia, Maurice Okello Obiero, Cyprian Ogombe Odoli, Casianes Owino Olilo, Philemon Orwa, Ashutosh Pandey, Saleh Ahmed Rabeh, Sid Ahmed Saadi, Sameer Srivastava, Usama Tahoun, Charu Vyas, Ashwini A. Waoo, and Hafsa Yaiche Achour

Published
2022

6. Zooplankton

Author

Luc Brendonck, Lizaan de Necker, Trevor Dube, Tatenda Dalu, Kay Van Damme, Tom Pinceel, and Tamuka Nhiwatiwa

Published
2022

8. List of contributors

Author

Alexandre P. Almeida, Xavier Armengol, Michael A. Barger, Alice F. Besterman, Ian Bredin, Luc Brendonck, Leandro Castello, Ross N. Cuthbert, Tatenda Dalu, Isaure de Buron, Lizaan de Necker, James B. Deemy, Layon O. Demarchi, Chris Dickens, Timothy Dube, Trevor Dube, Allison Durland-Donahou, C. Max Finlayson, Hervé Fritz, Ángel Gálvez, Madeline G. Garner, Marcelo Gordo, Richard Greenfield, Britney M. Hall, Jeffrey E. Hill, Kenneth Irvine, Nancy M. Job, Wolfgang Junk, Chad Keates, Nikol Kmentová, Elifuraha Laltaika, Aline Lopes, Wilmien J. Luus-Powell, Anne E. Magurran, Caston M. Makaka, Thomas Marambanyika, Robin L. McLachlan, Francesc Mesquita-Joanes, Musa C. Mlambo, Leandro J.C.L. Moraes, Sydney Moyo, Josphine Mundava, Peter Mundy, Tatenda Musasa, Grite N. Mwaijengo, Tongayi Mwedzi, Edward C. Netherlands, Tamuka Nhiwatiwa, Alan F.S. Oliveira, Maria E. Oliveira, Pia Parolin, Josephine Pegg, Maria T.F. Piedade, Tom Pinceel, Renata M. Pirani, Raíssa N. Rainha, Berel M. Rampheri, Todd C. Rasmussen, Martin Reichard, D. Christopher Rogers, Sukonthip Savatenalinton, Jochen Schöngart, Cletah Shoko, Erwin J.J. Sieben, Ariane A.A. Silva, Josie South, Kimberly K. Takagi, Tawanda Tarakini, Kaelyn N. Tyler, Kay van Damme, Maarten P.M. Vanhove, Bram Vanschoenwinkel, Ryan J. Wasserman, Fernanda P. Werneck, Olaf L.F. Weyl, Florian Wittmann, and Summer G. Wright

Published
2022

12. Food webs

Author

Ross N. Cuthbert, Ryan J. Wasserman, Chad Keates, Tatenda Dalu, Dalu, Tatenda, and Wasserman, Ryan J.

Published
2021

13. Challenges and possible impacts of artisanal and recreational fisheries on tigerfish Hydrocynus vittatus Castelnau 1861 populations in Lake Kariba, Zimbabwe

Author

Tatenda Dalu, Terence Magqina, Lindah Mhlanga, Mwazvita T.B. Dalu, and Tamuka Nhiwatiwa

Subjects
education.field_of_study, Multidisciplinary, biology, Fishing tournament, Population, Fishing, Breeding season, Artisanal fishing, Catch per unit effort, Socioeconomic factors, biology.organism_classification, Fish stock, Fishery, Overexploitation, Hydrocynus vittatus, Geography, lcsh:Q, Lake Kariba, Tigerfish, education, lcsh:Science, Recreation
Abstract

Increased fishing pressure from artisanal and recreational fishing has led to the collapse of some important fish stocks around the world over the past years. There is currently limited understanding of the impacts of recreational and artisanal fishing on tigerfish Hydrocynus vittatus populations in Lake Kariba and the socioeconomic factors behind them. Hence, this study investigated socioeconomic factors that act as drivers of the recreational and artisanal fishery industry and what sort of impact this would likely have on tigerfish H. vittatus populations using qualitative approaches. Eight three percent of the artisanal fishers interviewed recorded high catches during the summer season (October–February), which also coincides with the breeding season for tigerfish when it migrates up the rivers. Recreational anglers mainly caught females during the tigerfish tournament which is likely to have a significant effect on the tigerfish population in the long term through changes in tigerfish recruitment and other life history traits. Tigerfish size at sexual maturity and catch per unit effort which are all indicators of overexploitation were found to have decreased over the past years. Results further demonstrated increased fishing activities from artisanal and recreational fishing. It can be implied that the population of tigerfish may inadvertently be affected, but direct evidence that both recreational and artisanal fishing were having impacts on tigerfish populations was limited. It is therefore recommended that effective conservation measures such as preventing fish poaching during the tigerfish breeding season are put in place to protect the population and that of other fishes (i.e. potential prey).

Published
2020

14. Linking phytoplankton community structure to aquatic ecosystem functioning: A mini-review of the current status and future directions

Author

Naicheng Wu, Tatenda Dalu, GC Snow, and Daniel A. Lemley

Subjects
geography, education.field_of_study, geography.geographical_feature_category, business.industry, Aquatic ecosystem, Population, Environmental resource management, Estuary, Food web, Threatened species, Environmental monitoring, Phytoplankton, Environmental science, Ecosystem, education, business
Abstract

Globally, approximately 65% of aquatic ecosystems (i.e., freshwater, estuaries, marine) are considered threatened to some extent. Pressures on these fragile ecosystems are on the rise due to the demands for emanating from global human population increases. This chapter focuses on phytoplankton mostly diatoms and flagellates in environmental monitoring programs. It examines the different stressor-response relationships and phytoplankton traits using specific examples from the field. Using the obtained information, we created a pressure-stressor-response matrix relationship for phytoplankton use in biomonitoring. Thus, if the thresholds of potential concern (or there is sufficient weight of evidence) have been identified as being exceeded during monitoring, management options need to be identified to bring the ecosystem back to its original state. These ecological interpretations could prove particularly valuable as water management decisions, due to the potential impact of changes in microphytobenthos quantity and quality on the food web could be significant.

Published
2020

15. Contributors

Author

Francisco Gabriel Acién-Fernández, Hossein Ahmadzadeh, Cynthia Alcántara, Allan Victor Martins Almeida, Agostinho Antunes, Osamu Arakawa, Wagner L. Araújo, Neha Arora, Manabu Asakawa, Jose L. Barriada, Laura Barsanti, Eloy Bécares, Saúl Blanco, Aurélie Blanfuné, Silvia Bolado, Charles F. Boudouresque, Cristiane Canan, Naira Valle de Castro, Liliana Cepoi, Channakeshavaiah Chikkaputtaiah, Ann D. Christy, Eliane Colla, Jorge Alberto Vieira Costa, Rosana Aparecida da Silva-Buzanello, Kinue Daigo, Tatenda Dalu, Clinton J. Dawes, Deepi Deka, Deisy Alessandra Drunkler, Maranda Esterhuizen-Londt, Letícia Schneider Fanka, Cecilia Faraloni, José María Fernández-Sevilla, Pedro García-Encina, María Cruz García-González, Reimund Goss, Paolo Gualtieri, David Hernández, Roberto Herrero, Rubén Irusta, Damini Jaiswal, Torsten Jakob, Daneysa Lahis Kalschne, Ozcan Konur, Roberta da Costa Kosinski, Ana Larrán, Daniel A. Lemley, Pablo Lodeiro, Stephen Lyon, Violeta Makareviciene, Giorgos Markou, Joana Martins, Arthur C. Mathieson, Yukihiko Matsuyama, Anne Luize Lupatini Menegotto, J.S. Metcalf, Keisuke Miyazawa, Marziyeh Molazadeh, Michele Greque de Morais, Cristiana Moreira, Juliana Botelho Moreira, Raúl Muñoz, Tamao Noguchi, Bahareh Nowruzi, Adriano Nunes-Nesi, Ellis O’Neill, Tatsuya Oda, Hiroshi Oikawa, Sheyla Ortíz, Stephan Pflugmacher, Yimin Qin, Berta Riaño, Pilar Rodriguez-Barro, Sandrine Ruitton, Beenish Saba, Gisoo Sarvari, Manuel E. Sastre de Vicente, Egle Sendzikiene, Shinjinee Sengupta, Mostafa Shourian, Gavin C. Snow, Shashanka Sonowal, N.R. Souza, Thierry Thibaut, Cristina Tomás, Giuseppe Torzillo, Vitor Vasconcelos, Marcelo Gomes Marçal Vieira Vaz, Natarajan Velmurugan, Teresa Vilariño, Pramod P. Wangikar, Christian Wilhelm, Naicheng Wu, Inga Zinicovscaia, Hussein Znad, and Hamidreza Zohoorian

Published
2020

16. Fundamentals of Tropical Freshwater Wetlands : From Ecology to Conservation Management

Author

Tatenda Dalu, Ryan J. Wasserman, Tatenda Dalu, and Ryan J. Wasserman

Subjects
Wetland conservation--Tropics, Wetland management--Tropics, Wetland ecology--Tropics
Abstract

Fundamentals of Tropical Freshwater Wetlands: From Ecology to Conservation Management is a practical guide and important tool for practitioners and educators interested in the ecology, conservation and management of wetlands in tropical/subtropical regions. The book is written in such a way that, in addition to scientists and managers, it is accessible to non-specialist readers. Organized into three themed sections and twenty-three chapters, this volume covers a variety of topics, exposing the reader to a full range of scientific, conservation and management issues. Each chapter has been written by specialists in the topic being presented. The book recognizes that wetland conservation, science and management are interlinked disciplines, and so it attempts to combine several perspectives to highlight the interdependence between the various professions that deal with issues in these environments. Within each chapter extensive cross-referencing is included, so as to help the reader link related aspects of the issues being discussed. - Contributed to by global experts in the field of tropical wetlands - Includes case studies and worked examples, enabling the reader to recreate the work already done - Focuses on tropical systems not available in any other book

Published
2022

17. Emerging Freshwater Pollutants : Analysis, Fate and Regulations

Author

Tatenda Dalu, Nikita Tavengwa, Tatenda Dalu, and Nikita Tavengwa

Subjects
Fresh water, Water--Pollution
Abstract

Emerging Freshwater Pollutants: Analysis, Fate and Regulations comprises of 20 chapters, all written by leading experts. This book is written in the most practical terms and is easy to understand, with numerous helpful examples and case studies and can be used as a practical guide and important educational tool on issues concerning freshwater emerging pollutants. The organisation of the book exposes the reader in logical succession to the full range of complex scientific and management aspects of emerging freshwater pollutants in the developing world. The book recognises that water chemistry, emerging freshwater pollutants and management are inter-dependent disciplines. The book covers (i) the different monitoring techniques, current analytical approaches and instrumental analyses, (ii) fate and occurrence of emerging pollutants in aquatic systems and (iii) management policies and legislations on emerging pollutants. Thus, subsequent chapters elucidate chemicals with pollution potential, multi-detection approaches to analysis of organic pollutants in water, microplastics effects and photochemical transformation of emerging pollutants in freshwater systems. Whereas, other chapters address oxidation of organic compounds in aquatic systems, biomonitoring systems for detection of toxic levels of water pollutants, and health aspects of water recycling practices. This book melds several different perspectives on the subject of freshwater emerging pollutants and shows the interrelationships between the various professions that deal with water quality issues. Further, within the presentation of each separate chapter is discussion of how the various scientific and management aspects of the subject interrelate. - Includes case studies and practical examples in each chapter - Presents a much-needed interdisciplinary approach, representing the overlap between water chemistry and emerging freshwater pollutants - Provides a thorough introduction to emerging tropical and freshwater pollutants that typically occur in these systems

Published
2022

18. Muddy waters: efficacious predation of container-breeding mosquitoes by a newly-described calanoid copepod across differential water clarities

Author

Amanda Callaghan, Olaf L. F. Weyl, Ryan J. Wasserman, Tatenda Dalu, Neil E. Coughlan, Jaimie T. A. Dick, and Ross N. Cuthbert

Subjects
0106 biological sciences, education.field_of_study, biology, Ecology, 010604 marine biology & hydrobiology, Population, fungi, Context (language use), biology.organism_classification, 010603 evolutionary biology, 01 natural sciences, Freshwater ecosystem, Predation, Mosquito control, SDG 3 - Good Health and Well-being, Insect Science, Culex pipiens, education, Agronomy and Crop Science, Predator, Copepod, SDG 15 - Life on Land
Abstract

Mosquito-borne diseases induce unrivalled morbidity and mortality in human populations. In recent times, greater urbanisation has facilitated vector population expansion, particularly of those which proliferate in container-style habitats. To combat increased associated disease risk, we urgently require innovative and efficacious control mechanisms to be identified and implemented. Predatory biological control of vectorially-important mosquitoes can be effective. Despite their high prevalence in freshwater ecosystems, predatory calanoid copepods have yet to be examined comprehensively for mosquito control. Moreover, environmental context-dependencies can cause substantial variations in natural enemy impacts on target populations. Accordingly, improved understanding of the effects of context-dependencies upon predatory biocontrol is needed. Here, we use functional responses (FRs) to examine the predatory impact of a newly-described species of calanoid copepod, Lovenula raynerae, upon larval Culex pipiens prey across variations in prey supply and water clarity. Using outdoor field trials, we assess the viability of L. raynerae in reducing mosquito survival in container-style habitats. Lovenula raynerae displayed destabilising Type II FRs towards larval mosquito prey across all water clarities tested, with overall predation rates remaining largely unaffected across all clarity treatments. In the outdoor experiment, L. raynerae applications resulted in substantial reductions in larval C. pipiens populations, with close to total eradication achieved following the experimental period under higher predator densities. These results demonstrate that environmental context such as water clarity may have little effect on vector control by calanoid copepods, which suggests a predatory reliance on hydromechanical signalling. Further, for the first time, we demonstrate the applicability of calanoid copepods to artificial container-style habitats where mosquitoes proliferate. Therefore, our results indicate that further examination into the applicability of this species group to aid vector biocontrol strategies is warranted.

Published
2018

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