How climate change is affecting fishing production in Rwanda

By Emma-Marie Umurerwa

Before sunrise on Rwanda’s lakes, fishers push off hoping for a catch that will feed their families and stock the shoreline markets. But on Lake Kivu and Lake Muhazi, many say the seasons no longer follow familiar patterns rains hit harder, dry spells last longer, and the water is changing. As fish move, breeding zones shrink, and oxygen levels drop, mapping tools like satellite imagery and GIS are becoming a new way to see what the eye can’t where the lakes are under pressure, and where interventions could save livelihoods.

This comes at a time when Rwanda and Sub-Saharan Africa are trying to increase how much fish people eat each year, because consumption remains low compared to the global average.

On average, a Rwandan eats about 4–5 kilograms of fish per year, while the global average is around 16–20 kilograms. In Sub-Saharan Africa, the average is about 6.6 kilograms per person per year.

Figures from 2022 show that 44% of Rwanda’s fish production comes from Lake Kivu, which has 24 fish species, with the most common being sambaza, indugu, and tilapia.

Fish farmers say climate change is already affecting production

Ntwari Pacifique, one of 26 investors in fish farming in Rwanda and among the 12 who specifically farm tilapia in Lake Kivu says climate change has become a real challenge for fish farming.

He explains that weather changes can reduce oxygen levels in the water, yet fish need a certain amount of oxygen to breathe. Heavy rains and strong winds can also disturb fish and increase stress.

“Climate change causes oxygen to decrease, yet fish need a certain level of oxygen to breathe. When rainfall is heavy, things worsen. Sometimes landslides wash into the water… In 2023, landslides used to come into Lake Kivu, though it has reduced now because trees were planted along the shores. But climate change still affects us when it rains heavily, we don’t feed the fish so we don’t increase their stress. When rain and wind are strong, fish become stressed and disturbed, and feeding them can make it worse,” he said.

Ntwari, who farms fish in Bwishyura Sector, Karongi District, says he noticed that when he fed fish during very heavy rains, many would die.

He believes one practical solution is stronger environmental protection especially planting trees and grasses that hold soil along the lake’s shores.

“What can be done is to strengthen environmental protection, because in areas where trees and grasses were planted to hold the soil along Lake Kivu, fish deaths caused by lack of oxygen have reduced,” he said.

Past incidents show how serious the problem can become

In 2021, water levels in Lake Muhazi rose unusually high, and over 109 tons of fish died due to lack of oxygen.

Habineza Viateur, who fishes indugu in Lake Muhazi, says they often catch more fish during dark nights, but fewer when the moon is bright.

Rwigamba Claude, Leader of a fishermen’s cooperative in Gicumbi

Meanwhile, Rwigamba Claude, the leader of a fishermen’s cooperative in Gicumbi (Muhazi), says drought can happen in water just like on land.

“When it’s extremely hot on the hills, the water becomes very cold. Fish look for warm areas and stay there, and during that time we don’t catch fish,” he explained.

Lake Kivu residents say the water and fish stocks are changing

Nishimwe Clenie, from Bwishyura Sector, who has been swimming in Lake Kivu for more than 23 years, says the lake water is no longer as clean as it used to be.

“When I was young it wasn’t as bad as it is today. Rain used to fall on time, and floods were not common. Lake Kivu water looked clean, fishing was going well, and sambaza were available. But now cleanliness is low… the water looks bad, and sambaza don’t reproduce well, so the price rises. Before, a kilo cost 1,000 francs, but now it has reached 4,500 francs for the best quality,” she said.

Fish is becoming harder to afford for some families

Data from 2023 indicates that Rwandans eat around 4 kilograms of fish per year, yet internationally, people are encouraged to eat at least 11 kilograms annually to support healthy brain and heart function.

Mukaturatsinze Jeannette, from Gicumbi District, says many people often choose indugu because it is cheaper.

“A kilo of indugu costs between 600 and 1,000 francs. They are easier to catch during dark nights, because when fishermen use traps on moonlit nights, the fish see them and escape,” she said.

Fishermen in Karongi say changing water levels and erosion are reducing sambaza

Ndagijimana Emmanuel, head of the federation of fishermen’s cooperatives in Karongi, says Lake Kivu’s water levels rise a lot during the rainy season and drop during the dry season, affecting sambaza.

“It affects sambaza production because when sambaza want to reproduce, they lay eggs along the shore. When the water level is unstable, the young sambaza don’t grow well and many die,” he said.

When the weather is favorable, they get a good fish harves

Sibomana Jean Bosco, coordinator of the fishing project in Karongi (Projet Pêche Kibuye – PPK), adds that climate change has increased erosion. More intense rains wash soil into rivers that flow into Lake Kivu, which then affects fishing.

Climate change is reducing fishermen’s catches and overall fish production.

“In fishing, we use a lamp at night so sambaza follow the light into the water. When there is too much erosion in Lake Kivu, sambaza can’t see the light properly, and production drops,” he said.

Authorities and experts call for stronger protection and smarter technology

Kimenyi Martin, from Rwanda’s agriculture and livestock board (Gakuta branch serving Rutsiro and Karongi), says they are focusing on protecting riverbanks and lake shores to create safer breeding areas for fish.

“There is a program to plant bamboo along rivers that flow into Lake Kivu, and to stop people from farming or building within 50 meters of the lake. This helps fish grow well because they get safe breeding areas,” he said.

RAB: Combine efforts’ to protect livelihoods

Cecile Uwizeyimana, Fisheries and Aquaculture Office at RAB, says climate change is increasingly affecting both capture fishing and fish farming in Rwanda. She explains that higher water temperatures, unusual rainfall, floods, and longer dry spells are disrupting fish growth and breeding, increasing disease risks, and reducing overall yields.

“A long-term solution is to combine efforts: protect lake and river banks, follow fishing regulations, and invest in sustainable fish farming so livelihoods are not lost.” She said.

Note: Coordinates are approximate, based on the locations named in the story (not GPS points from the field).

Dr. Apollinaire William, a University of Rwanda lecturer and biodiversity expert, says rising temperatures in Africa are shrinking lakes in dry regions and increasing erosion in lakes. As water warms, dissolved oxygen decreases, which harms fish especially eggs and young fish reducing overall production.

“As lake water warms, dissolved oxygen decreases, affecting fish breathing especially eggs and very young fish so production can drop.

In Lake Kivu, when temperatures rise, the small organisms that feed sambaza reduce, and sambaza go hungry,” he explained.

Dr. William recommends using GIS technology to monitor how erosion pollutes water, track how aquatic life migrates due to temperature changes, and map waste brought in by runoff.

He also proposes practical actions such as planting trees and grasses along rivers and lakes, pausing fishing during breeding periods, avoiding nets that catch young fish, using climate-resilient fish farming methods (aquaculture), and asking fish buyers to show where they bought fish to reduce smuggling.

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