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Kenya, which straddles the equator between the Indian Ocean and Lake Victoria, may be better known for its terrestrial wildlife species, but the East African country also encompasses some of the continent’s most important marine environments. Along its coastline are “super reefs” that scientists now think may be more adaptable to withstand rising ocean temperatures brought on by global climate change if their fisheries resources are properly managed. Kenya’s marine ecosystems range from mangroves and coastal wetlands to lagoons, coral reefs and open ocean; the country has six national reserves designed specifically to protect its marine environments.
- The green turtle, hawksbill turtle, and olive ridley are the most commonly encountered sea turtles in Kenya.
- The Kenyan coastline is protected by a fringing reef that runs nearly its entire length.
- Coral reefs are composed of tiny creatures that live in colonies in mostly tropical and subtropical waters.
- During prolonged, unusually high surface temperatures, many coral species discharge the beneficial algae that live within the tissues and “bleach,” leaving the reefs white and sickly. Reefs living in environments with stable but higher temperatures are more susceptible to fatal bleaching.
Increased development along the coastline can generate runoff, impact water flows, and cause sedimentation in Kenya’s coastal waters. But the greatest threats to the country’s marine ecosystems are unsustainable levels of fishing and the impacts of global climate change, both of which have wrought havoc on the Indian Ocean’s coral reefs. Economically poor communities that rely heavily upon marine resources tend to use traditional, low-tech fishing methods. When a community becomes wealthier, it often uses more motorized fishing vessels and sophisticated fishing gear, which are more destructive, even if the community relies less on fishing for subsistence. Economic growth can also erode cultural restrictions on overfishing, which has happened in Kenya.
WCS researchers are determining how human communities living adjacent to reefs in southern Kenya adapt to the impacts of climate change. When reefs die off, their valuable fish stocks disappear and tourism dollars dry up. WCS is working to improve coral reef fishery management to relieve stress on these ecosystems. Ultimately, conservationists hope to help provide wider economic opportunities to local communities dependent on reef fishing.
In addition, WCS researchers are finding ways to help reduce the negative impacts of climate change and potentially increase the resilience of marine ecosystems by managing fishing gear. Different types of equipment used by artisanal fishers target fish with various effects on the coral reef ecosystem. At our study sites in Kenya, WCS has observed that traps and spear guns are used to harvest many fish populations that are key to the recovery of
corals that have “bleached” as a
result of warming surface waters. For example, herbivorous fish that
graze on algae help keep the ecosystem in balance, enabling corals to
flourish. When these fish disappear from the waters, the reefs become
significantly more prone to the detrimental effects of climate change. Conservationists hope that by selectively banning or restricting certain fishing gear that take too great a toll on crucial reef fish, they can develop a powerful tool to combat the detrimental effects of climate change.
WCS scientists studying the reefs in the Indian Ocean off Africa’s east coast have found that corals with the best chances of survival live in seas with wide-ranging seasonal temperatures. These hardier reefs tend to be located in the “shadow” of islands, protected from the oceanic currents that keep temperatures stable in more fragile reef ecosystems. Our scientists are now mapping the global stress on corals in the Indo-Pacific Ocean.
Coral reefs, sometimes referred to as “the tropical rainforests of the oceans,” contain some of the most diverse concentrations of life on the planet. As the surface temperature of the ocean warms, these fragile ecosystems are prone to bleaching events, and eventually, to death. WCS marine researchers map the global stress on corals throughout their range, and study which reefs are most resilient to environmental changes.
From the Newsroom
WCS marine scientists provide a color code for coral conservation by mapping out the stress loads of the world's reefs.
An archaeological study by a WCS marine researcher in Kenya compares fish
communities from modern times with those from the Middle Ages. The scientist finds that
the modern fish are overwhelmingly smaller, lower on the food chain, and
WCS has developed a stress test to map out which coral reefs will have the best chance of surviving through the climate change era.
A long-term WCS study off the Kenyan coast finds overfishing in coral ecosystems can stunt the growth of reefs.