Shanga, Kenya. Spanning some 650 years, the refuse heaps provided the researchers with valuable insights into how fish assemblages and fishing pressures changed during that time span.
The researchers discovered that the life histories of fish caught by mod-
ern fisheries and the remains of ancient fish assemblages were significantly
different. Whereas ancient fish communities had a high percentage of top
predators—species that prey on fish and large invertebrates such as snails,
sea urchins, and clams—modern fish communities contain more species that
feed on plants and small invertebrates like sea lice, generally smaller species
that feed lower on the food chain. Modern fish assemblages also contain Acanthurus lineatus: smaller herbivores are increasing as large predators disappear.
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more species that are smaller in size and have higher growth and mortality
rates.
The researchers also found that the number of fish bones in the middens
peaked between AD 1000 and 1100 (approximately 1000–900 BP) before
declining, while the bones of sheep and goats become more prevalent in the
higher levels of substrate, suggesting a shift in human diet to domesticated
animals.
“The archeological evidence demonstrates the incredible longevity of hu-
manity’s utilization of coastal fisheries, while emphasizing the critical need
to actively manage slower-growing, longer-lived species within an ecosystem
approach,” said Dr. Caleb McClennen, Director of WCS’s Marine Program.
“The evidence from Kenya aligns with findings from around the world that
for millennia, humanity has relied on the world’s oceans for its basic needs—
but has more recently failed to do so in a manner that also will sufficiently
sustain that resource.”
From Fiji to Kenya to Glover’s Reef, Dr. McClanahan’s research has been
examining the ecology, fisheries, climate-change effects, and management of
coral reefs at key sites throughout the world. This work has been supported
by the John D. and Catherine T. MacArthur Foundation and The Tiffany &
Co. Foundation.
htim mcclanahan/wildlife conservation society
SOURCE
wildlife conservation society, http://www.wcs.org/
