Posted on | April 16, 2010 | Comments Off on Researchers Find Biodiversity Hotspot in Undersea Canyons
Mānoa researchers conducted the first extensive study of canyons in the oceanic Hawaiian Archipelago and found that these submarine canyons support especially abundant and unique communities of megafauna (large animals such as fish, shrimp, crabs, sea cucumbers and sea urchins) including 41 species not observed in other habitats in the Hawaiian Islands. Underwater canyons have long been considered important habitats for marine life, but until recently, only canyons on continental margins had been intensively studied. The research was published in Marine Ecology.
To conduct the research off Oʻahu, Molokaʻi and Maro Reef, lead author Eric Vetter, Professor Craig Smith and doctoral student Fabio De Leo took turns in Hawaiʻi Undersea Research Laboratory submersibles Pisces IV and Pisces V counting marine life on the ocean bottom.
The results of the 36 surveys showed that the highly mobile megafauna (like fish, sharks, shrimp and squid) were much more abundant in the canyons than on the open slopes at all depths studied. This suggests that canyons provide an especially good habitat for mobile species that are able to feed on accumulated organic matter but can escape the physical disturbances in canyons resulting from high currents and mobile sediments (e.g., migrating sand ripples).
“Perhaps the biggest surprise of this study was the large number of species, 41, that we found only in canyon habitats,” says Smith. “This suggests that canyons support a substantial specialized fauna that would not exist in the Hawaiian archipelago in the absence of canyons. Thus, submarine canyons are contributing uniquely to biodiversity in the islands and merit careful attention for environmental protection and management.”