Elegant Red Alga (Phycodrina elegans)
The elegant Red Alga was a marine algae species that was endemic to the ocean surrounding the Galápagos Islands, and it appears to have been very common in former times.
The species disappeared after or during a devastating El Niño event that took place between 1982 and 1983. However, the removal of lobsters and other fish predators from the environment by local fishers lead to a cascade of direct and indirect effects involving explosive population expansion of grazing (algae-feeding) sea urchins.
This again lead to the complete extinction of several endemic marine algae species from the waters around the Galápagos archipelago that happened almost unnoticed by the public.
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References:
[1] Graham J. Edgar; Stuart A. Banks; Margarita Brandt; Rodrigo H. Bustamantes; Angel Chiriboga; Lauren E. Garske; Peter W. Glynn; Jack S. Grove; Scott Henderson; Cleve P. Hickman; Kathy A. Miller; Fernando Rivera; Gerald M. Wellington: El Niño, grazers and fisheries interact to greatly elevate extinction risk for Galapagos marine species. Global Change Biology 16: 2876-2890. 2010
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edited: 29.11.2018