Category: MIL-OSI

Source: The Conversation – Africa – By Diane Le Gouvello, Postdoctoral fellow, Nelson Mandela University

All sea turtle species are threatened worldwide. They migrate long distances in the oceans – often thousands of kilometres – and so fall under multiple countries’ laws and conservation targets. They also have a complex life cycle with changes in habitats and diet at different life stages. These things make it difficult to protect them from threats like illegal harvesting, fisheries bycatch, coastal development, diseases and pollution.

Although they predictably return to the same nesting grounds on beaches where they were born, and the movements of adults have been well studied (mostly using satellite tracking), very little is known about their early life. Once newly hatched turtles enter the sea and disperse, they are gone for several years, also known as the “lost years”.

It’s hard to track hatchlings because they are small (just a few centimetres long), many die, and the survivors grow fast (so tracking devices don’t stay on). But knowing more about where they go during these “lost years” would help conservation scientists to improve their chances of survival and thus ensure recruitment and population viability.

Computer models are valuable tools for predicting the distribution of organisms in the oceans. The Sea Turtle Active Movement Model, for example, has been used to suggest how young turtles might disperse in the North Pacific and North Atlantic oceans – not only drifting in currents but actively swimming to their preferred habitats. The two most important factors are water temperature and food availability.

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Read more: Seychelles: floating baby corals can help save damaged reefs – new study

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I was part of a team of scientists in South Africa who worked with the creators of that model to set up a similar one for the western Indian Ocean turtles. These are the species that nest on the eastern coast of the African continent and offshore islands.

We knew something about the surface currents in the Indian Ocean, the sea temperatures, the tiny hatchlings’ swimming speed, their starting points, what food they might need to find, and their growth rate. All this could be combined in the model to calculate where they might be at different points in time. The model produced maps predicting the distribution of dispersal for each species of sea turtle in the western Indian Ocean.

We found that ocean currents were the most important driver of dispersal, as hatchlings’ swimming abilities are limited during the first year. Swimming becomes more important as the young turtles grow.

This was similar to the findings of other studies.

Young turtles don’t stay inside marine protected areas all the time. The maps we created can be used to show where and when they might be most vulnerable and which areas of the ocean are most important to protect.

Indian Ocean turtles

We chose to model the sea turtles of the western Indian Ocean for a few reasons. There are five species that nest here; all the countries on this coastline and offshore islands have turtle conservation and monitoring programmes; and the ocean currents are complex.

The five species are green turtles (Chelonia mydas); hawksbills (Eretmochelys imbricata); loggerheads (Caretta caretta); leatherbacks (Dermochelys coriacea); and olive ridleys (Lepidochelys olivacea, which nest in smaller numbers and have not been included in our model). We had already studied their hatchling fitness, including their different swimming speeds, which was information the model would need.

The protected areas include South Africa’s iSimangaliso Wetland Park, a Unesco World Heritage Site. The turtle rookery there is about 200km long and has been monitored since 1963.

Our model also incorporated a high resolution ocean model of the Mozambique Channel, a very turbulent and dynamic oceanic region. It mostly flows southward, but eddies also send surface water in all directions. At the western end of the channel’s Agulhas Current, the Agulhas Rings also transport water into the South Atlantic Ocean, connecting the two ocean basins and a potential route for young turtles.

Water temperature matters too. Sea turtles do not regulate their own body temperature and the newly hatched turtles are less tolerant of temperature changes than adults are, but vary depending on the species. Temperature is more important for their survival than food is (their food requirements are easily met during the first year, as they are so small).

The model uses data on surface ocean currents and primary productivity (as a proxy for food availability). For each nesting site and species, we “released” 5,000 “virtual hatchlings” over a one-month period of peak hatching. The daily location of each virtual hatchling was recorded over one year. The model simulated young turtle dispersal and thereby estimated their potential distribution at an individual level. We then analysed this to predict their dispersal corridors at the population level.

Where young turtles go

The study revealed that the young turtles mostly go from their hatching site to a particular developmental area (the place where they develop for the first years) even though these are sometimes very far apart. Dispersal is mostly driven by ocean currents (during the first year) but differs among species. When they are older, currents are less important in their dispersal, and they start to actively swim towards favourable ocean areas.

There were three distinct dispersal corridors: among equatorial Indian Ocean islands (hawksbills); along east Africa (green turtles); and around southern Africa (loggerheads and leatherbacks).

The study allowed us to predict and map where critical dispersal habitats might be for four species nesting in this ocean region. It’s the first study to provide a regional-scale estimate of the dispersal pathways and corridors used by young turtles (individually and as populations), which are usually lacking in conservation assessments.

The results can also assist to develop more targeted management measures for conservation managers and policy makers, which will enhance the protection afforded to each of these threatened migratory species. The UN’s new high seas treaty will be instrumental in extending these actions into areas beyond national jurisdiction.

– Baby turtles vanish into the Indian Ocean for years: now a model shows where they might go
– https://theconversation.com/baby-turtles-vanish-into-the-indian-ocean-for-years-now-a-model-shows-where-they-might-go-261576

Source: The Conversation – Africa – By John Mukum Mbaku, Professor, Weber State University

In April 2011, Ethiopia began construction of Africa’s largest hydroelectric dam, the Grand Ethiopian Renaissance Dam (GERD), on the Blue Nile river. The dam is expected to generate more than 6,000 megawatts of electricity, effectively transforming Ethiopia into the continent’s largest power exporter.

The dam affects 11 countries, two downstream and nine upstream.

Addis Ababa completed construction of the US$4 billion-plus project in July 2025, mainly with funds sourced from Ethiopians at home and in the diaspora, with an official launch on 9 September 2025. John Mukum Mbaku, who has researched the governance of the Nile’s waters, explains the dam’s potential for Ethiopia – and the controversies that have dogged it.

What are the simmering tensions around the official launch of the dam?

The dispute over the allocation and use of the Nile waters has been going on for many years. This has been exacerbated by climate change, and increased demand for food and water from growing populations.

The 11 countries that share the waters of the Nile have competing development priorities too. These states include Ethiopia, Egypt, Sudan, Rwanda, Tanzania and Kenya.

Egypt and Sudan lie downstream. They receive the river’s waters only after it has passed through the nine upstream states.

Initially, the downstream states, particularly Egypt, opposed the construction of the dam, arguing that it was a threat to their water rights.

However, Ethiopia powered ahead with construction. Egypt and Sudan then shifted negotiations to securing an agreement for filling and operating the dam.

The two downstream states had suggested that filling the dam should take about 12 to 21 years in order to protect their water supply. For domestic and political reasons, Addis Ababa prefered a shorter filling period. In addition, Egypt and Sudan argued that filling the reservoir without a legally binding agreement would disregard their interests and rights.

But with the dam now fully filled and due to be officially inaugurated on 9 September 2025, the issue of a binding agreement for filling the dam’s reservoir is moot.

Egypt and Sudan’s political and diplomatic efforts highlight what they say is the illegality of unilaterally operating the dam without a binding agreement. Despite the intervention of the African Union and the US government, as well as appeals by Egypt to the UN Security Council, the three countries haven’t been able to secure a deal.

Part of the reason is that Egypt has insisted that any negotiations on water allocation begin with the rights granted to it under its 1959 Nile Waters Treaty with Sudan.

Under this agreement, Egypt was granted 66% of the Nile’s estimated average annual water flow of 84 billion cubic metres. Sudan got 22%. The treaty ignores upstream countries’ legal claims to Nile waters, since 10 billion cubic metres were reserved for seepage and evaporation. Ethiopia’s highlands, for instance, supply more than 86% of the water that flows into the Nile River.

Egypt continues to argue that Ethiopia’s dam is a threat to its water security and that, if necessary, it will take measures to protect what it refers to as its “historical rights” to Nile waters.

Egypt relies on the Nile for more than 90% of its fresh water supplies. The country’s water needs have risen as its population has grown and its economy has expanded significantly.

However, Egypt and Sudan’s insistence on keeping their historical water shares cannot be considered equitable and reasonable. Additionally, Cairo doesn’t appear to be prioritising a water-use approach that acknowledges the legal claims of upstream states to the Nile’s waters.

Instead of improving and updating its water infrastructure, minimising wasteful irrigation practices and generally improving water use, Egypt has focused on grandiose mega projects that are putting significant stress on the region’s scarce water resources.

Sudan, which has been battling a devastating civil war since 2023, has raised concerns about Ethiopia’s dam affecting the operations of its own dams. This would make it more difficult to manage Khartoum’s development plans.

What makes agreement on the Nile so elusive?

The legal framework regulating the allocation of the Nile’s waters has been dominated by colonial-era agreements. These have been embraced by the two downstream states, Sudan and Egypt, but contested by the nine upstream ones.

Two of the most important of these agreements are the 1929 Anglo-Egyptian Treaty and the 1959 Egypt-Sudan treaty.

The 1959 treaty augmented the water allocations granted to Egypt and Sudan by the 1929 Anglo-Egyptian Treaty. These treaties also granted Egypt veto power over any construction projects on the Nile or its tributaries.

The terms of these treaties, however, are only possible if the nine upstream riparian states don’t access or utilise any water from the Nile and its tributaries.

Most importantly, they make the water rights of the other Nile countries dependent on Egypt and Sudan’s goodwill.

Ethiopia and other upstream states have long argued that they were not parties to the colonial-era treaties and are, therefore, not bound by them.

What international principles guide water use across borders?

The pillars of international transboundary water law are:

(i) equitable and reasonable use

(ii) the obligation not to cause significant harm

(iii) the duty to cooperate.

International legal scholars have noted that the 1959 Nile Treaty stands in sharp contrast to these principles. It disregards the sovereign rights of other riparian countries to their fair share of the Nile, and interferes with their development.

What does the dam promise for Ethiopians?

The Grand Ethiopian Renaissance Dam is a symbol of national unity and pride. It is significant that construction was undertaken without reliance on financing from external actors, such as international financial institutions or major industrial countries.

The dam’s electricity output could potentially transform Ethiopia’s development.

First, the electricity would provide a reliable source of energy for rural industrialisation, reducing deforestation by eliminating the need for households to cut down trees for firewood.

Second, it would reduce the pollution associated with burning wood, dung and other forms of biomass for cooking and other activities.

Third, it would improve access to education, effectively providing light that enhances the ability of pupils to complete homework assignments and study at night. During hot seasons, the electricity generated could be used to cool classrooms, improving learning outcomes.

Finally, higher electricity output would boost internet connectivity in rural areas in Ethiopia, effectively boosting access to the outside world.

The dam could also help with flood control in Sudan and drought protection in Egypt – but only if the three countries work together.

– Ethiopia’s mega dam has taken 14 years to build: what it means for the Nile’s 11 river states and why it’s so controversial
– https://theconversation.com/ethiopias-mega-dam-has-taken-14-years-to-build-what-it-means-for-the-niles-11-river-states-and-why-its-so-controversial-264665