The ecosystem of the Mara River

Interview with scholarship holder Mildren Juma

With its scholarship, Berlin World Wild supports young conservationists around the world with a concrete connection to the long-term protection of endangered species and habitats. The commitment of the seven people from Africa, South America and Asia makes an important contribution to the preservation of biodiversity. In this interview, scholarship holder Mildren Juma talks about her work, her motivation, but also about the difficulties involved in species conservation work. More information about the scholarship, the scholarship holders and their projects can be found here.

What is your name? What do you do and what are you researching?

My Name is Mildren Achieng Juma. I am a research fellow at the National Museums of Kenya, Zoology Department, Ichthyology section. Equally, I am a graduate student pursuing a Master of Science in Biology of Conservation. My research work involves a study on fish species in the Mara river ecosystem in Kenya.

Tell us more about what fascinates you about ichthyology – the study of fish? Please tell us more about aquatic life in Kenya.

My first interest in ichthyology was sparked during my industrial attachment during my undergraduate studies other than part of my origin being from a community of Fisher folks. I was an attaché at the Kenya Marine and Fisheries Research Institute in 2017. Here I gained early practical experience in the field, starting with setting the fishing nets in the evening hours when the wind was strong blowing over the lake and waking up at dawn to remove the nets. Sometimes we worked in rough water that beat against our boats as if it would break them, and sometimes during encounters with hippos that woke up in a good mood that day and threatened to overturn the boat.

Despite the many adventures involved, we obtained varied results from the daily research findings. It ranged from aspects defining the ecological health of the water, to samples of the fauna and flora dwelling within the lake up to indicators of the economic benefit of the lake to the communities residing around the lake and dependent on the lake for their daily livelihood.

Monitoring all these during the time, my interest in Ichthyology got sparked to date. With time, I advanced my knowledge on different aspects of aquatic life. I came to learn that fish comprises slightly over 50% of all vertebrates. New fish species are discovered or re-described every year more than any other vertebrates in Kenya and globally, which adds to my curiosity about the existing knowledge gaps in this field and makes me wonder how I can best contribute to filling these gaps. My current experience on aquatic habits during fieldwork, as a research fellow at the Ichthyology section of the National Museums of Kenya, has given me a vast broadening of my understanding, knowledge and experience on fisheries and aquatic life. Although, challenges are still there, e.g. encounters with wild animals such as crocodiles, hippos and adult monitor lizards and floods making the  research areas inaccessible while in other geographical regions within the country the continual change of climate has led to prolonged drought altering the hydrological cycle of the area leading to death of aquatic life. We have managed to get fascinating findings on interesting species of fishes, there are those with ecological value as bio indicators to ecosystems health as fishes of the genus Amphilius e.g. Amphilius lujani, some have evolved numerous survival strategies to cope with environmental changes like Protopterus aethiopicus which hibernates the entire dry seasons while other species undertake remarkable migrations for breeding to avoid harsh conditions such as Labeo victorianus.

What does your typical field day or working day looks like?

My typical working day mostly begins early. I review my schedule for the day and prioritise the work to do for the day. Considering the nature of my work, the activities may vary with the day. In the case of offices work, my work may involve data entry, data analysis, report writing, literature reviews, educating and training students and visitors, sometimes assisting in organizing workshops or conferences and presenting results. During lab sessions, I am involved in the morphometrics, meristics, Identification and proper preservation of the specimens sampled during the field works.

When preparing for field days I am busy gathering necessary field equipment, data collection tools and supplies. Being in the field includes travelling to remote natural areas, conducting research surveys lasting for several hours, setting up monitoring equipment, taking measurements, fishing, documenting habitats and ecological patterns and observing present wildlife in the study area. All of this while following protocols and adapting to the change in the environment as needed.

Do you find your work easy or are there also obstacles (weather, animals are hard to find,...)?

I have gained resourceful experience overtime which has enabled me to gain skills and expertise that ease my efficiency in doing the work. Provision of suitable tools, working with chemical reagents, adjusted human resource and sometimes advanced training to cope with the technological change provides an enabling environment to work efficiently. When it comes to office work, a database system that collates all the data that is only accessible to one person behind a computer makes it easier to document and retrieve information. The existing analysis software, which is able to run analysis of large data sets helps to achieve sound results and conclusions when creating a report.

Although, when it comes to some of the reagents used in the laboratory processes, some are unpleasant in nature and to some extreme extent intolerant if exposed to them for a longer period of time. The development of more tolerant and pleasant reagents in the future is desirable, even if we always handle the reagents with care and take the necessary precautions when handling them. In addition to climate change, which has led to flooding in the study areas, making the areas inaccessible, data collection in the field also faces dangers from wild animals such as lions, elephants and buffalo, which sometimes mock attack us even though we are equipped with wardens and security on land. Most cases there is no security provided when being on the waters which at times are infested with crocodiles and hippos that can be challenging. Regardless of these hazardous situations, we have learnt over time how best to behave while doing data collection in such areas. This has enabled us to become resilient, cautious and more adaptable in harsh environments, making it adventurous and the work more rewarding in the long run through the discoveries we make.

How does your work contribute to the conservation of biodiversity?

My work is part of the research on the ecological gradient of fish along the study area, which makes it possible to monitor the diversity and abundance of these species along the different gradients and to show their distribution patterns, which may help to determine the habitat range. The presence of a species along the ecological gradient indicates the range of suitable habitats along the ecosystem. Protection of these ecosystems benefits fishes and other aquatic organisms while contributing to biodiversity conservation as well. Observation of some fishes which are bio indicators of ecosystems health, whereby a decline of these fish species are an indication of environmental degradation, allows conservationists to safeguard the ecosystem’s health by prompting conservation actions to prevent further damage.

Additionally, maintaining a diversity of fish species plays a vital role in maintaining ecosystem balance within an ecosystem since they act as both prey and predator regulating the population of some aquatic species such as zooplanktons and macro invertebrates. These diverse array of fish species in the ecosystem contributes to resilience and stability of the system as a whole.

For example in the case of some migrating fish species, mainly those that migrate upstream into the head waters from the lake for the brooding season, negatively impacting anthropogenic activities along the riverine ecosystem can be observed through study of such species that helps determine the man-made impacts along the gradient of the river. Therefore, community education focusing on adapting positive practices along the river’s ecosystem is a way of promoting citizen science which will contribute to managing and protecting fish populations along varying environmental conditions. This contributes to conserving ecosystem health, maintaining ecological balance and preserving genetic diversity and in the long run promoting a sustainable use of natural resources for benefit of wildlife and the people.

What main thing for the nature in Kenya do you wish to achieve?

Globally, and particularly in Kenya, there has been a massive decline in freshwater biodiversity, leaving a large gap in the current diversity of freshwater flora and fauna. Through the work I am doing, I hope to contribute to close the existing gap or to at least or at least contribute to limiting the loss.

Finally, would you like to give us something to take away with us?

Here is a website link of the dataset of some of the species we encounter during field work:

Fish species occurrences in the rivers of the Lake Victoria Basin Kenya, digitized from the Ichthyology specimen collection at the National Museums of Kenya (

University of Florida (2022) - JRS Biodiversity Foundation

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