The need to improve food security in Africa through culture of tilapias has led to transfer of different species from their natural ranges causing negative impacts on wild fish genetic resources. Loboi swamp in Kenya is fed by three hot springs: Lake Bogoria Hotel, Chelaba and Turtle Springs, hosting natural populations of Oreochromis niloticus. The present study aimed at better genetic characterization of these threatened populations. Partial mtDNA sequences of the D-loop region and variations at 16 microsatellite loci were assessed in the three hot spring populations and compared with three other natural populations of O. niloticus in the region. Results obtained indicated that the hot spring populations had mitochondrial and nuclear genetic variability similar to or higher than the large closely related populations. This may be attributed to the perennial nature of the hot springs, which do not depend on rainfall but rather receive permanent water supply from deep aquifers. The study also revealed that gene flow between the three different hot spring populations was sufficiently low thus allowing their differentiation. This differentiation was unexpected considering the very close proximity of the springs to each other. It is possible that the swamp creates a barrier to free movement of fish from one spring to the other thereby diminishing gene flow. Finally, the most surprising and worrying results were that the three hot spring populations are introgressed by mtDNA genes of O. leucostictus, while microsatellite analysis suggested that some nuclear genes may also have crossed the species barrier. It is very likely that the recent intensification of aquaculture activities in the Loboi drainage may be responsible for these introgressions. Taking into account the importance of these new genetic resources, protection and management actions of the Loboi swamp should be accorded top priority to prevent the loss of these spring populations.

In this study, we use geometric morphometric method to establish morphological differences between natural populations of Nile tilapia from two extreme environmental conditions (high temperature and salinity) in Kenya, and compare them to two populations from regions experiencing less extreme conditions. To determine genetic influence on morphology, we correlated genetic data with morphological data. The study observed significant morphological differences between all studied populations, including three closely related hot spring populations (Bogoria, Chelaba and Turtle Springs), and two populations with similar genetic background inhabiting saline environments in Lake Turkana basin (Turkana and Crocodile Lake populations). In addition, allometric growth patterns of the seven populations differed significantly, demonstrating that developmental changes (plastic or adaptive) operated between these populations. Positive correlation between morphometric and genetic data confirmed the influence of genetic factors on morphology. All observed differences were attributed either to genetic and/or environmental factors, which seemed to play a major role in influencing morphology of wild Nile tilapia populations. We recommend further studies to be carried out under controlled conditions to confirm the role of temperature, pH and salinity in morphological diversification of Nile tilapia.

No abstract

High rates of species radiation have been recorded in Cichlids of East African lakes. The current study focused on a population of Nile tilapia (Oreochromis niloticus) found in a crater lake (Lake Crocodile) that occurs within the Central Island of Lake Turkana. The population separated from Lake Turkana about 100 years ago and has since then existed in isolation. This study aimed at assessing the existence of genetic differences between the Lake Crocodile Nile tilapia population and other closely related Nile tilapia populations from Lake Turkana, Lake Baringo and River Suguta. Genetic differences between the populations were evaluated using two mtDNA markers, and 16 microsatellite markers. Significant genetic differences (p > 0.05) were observed between the Lake Crocodile population and the other studied populations within the region. Despite the shared ancestry between Lake Crocodile and Lake Turkana, genetic differences were observed between the two populations. This can mostly be attributed to the lack of gene flow and environmental differences between the two populations.

Pastoralists living in the arid and semi-arid areas of Africa have for centuries coexisted with wildlife. They frequently share the same environmental resources with wildlife, are exposed to common risks including disease and drought, and in some cases, and are antagonistic to one another, particularly when competing for limited resources. In recent years, negative interactions between wildlife and humans have increased due to the decline of wildlife habitat, which has led to greater conflict. In the Meibae Community Conservancy, there has been a concern in recent years over increased human-wildlife conflict. Retaliatory killings raised concerns for the conservation of carnivore species. This study evaluated the effectiveness of non-lethal mitigation measures, in particular the use of predator deterrent lights, in reducing night attacks on livestock by large carnivores in Meibae Community Conservancy. The study assessed the effectiveness of the technique by determining the number of predator visits using tracks and sightings both at homesteads fitted with light units, and those without deterrents. The findings indicate that homesteads fitted with flashing deterrent lights recorded a lower number of visits by predators (2.4 visits/homestead) compared to those without lights (3.4 visits/homestead). Despite finding no significant difference (p>0.05) in the number of visits for homesteads with lights and those without lights, this study concluded that flashing deterrent lights have the potential in reducing cases of successful livestock attacks at bomas even though predators remained inquisitive. Flashing lights can contribute to the conservation of large carnivores by reducing conflicts between predators and livestock owners.