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Gorilla Ogo (Gracilaria salicornia)

Gorilla Ogo close upIdentifying Features:

• Cylindrical, brittle branches
• Branching irregular, often forked at tips
• Tips bluntly rounded
• Varies in color from a bright yellow at the tips to orange or green and then even dark brown at the base
• Intertidal to subtidal to 4 m

Description

Plants branches are brittle, cylindrical, 2-5 cm in diameter.  Branching irregular, often forked at tips and constricted at base of forks with tips bluntly rounded.  Varies in color from a bright yellow at the tips to orange or green and then even dark brown at the base.

GRACILARIA mapDistribution

Hawai‘i: O‘ahu, Hawai‘i Island, Moloka‘i.
Worldwide: Wide spread throughout the warm Indian and Pacific Oceans.
Mechanism of Introduction:  First found in 1971 in Hilo Bay, Hawai‘i. Introduced to Kane‘ohe Bay and Waikiki in the 1970’s

Habitat

Gorilla Ogo forms dense clumps

Gorilla Ogo forms dense clumps

Gracilaria salicornia is found in tidepools and on reef flats, intertidal to subtidal 4 meters deep, attached to limestone and basalt substrates. Intertidal plants often without constrictions, subtidal with constrictions.

 

Ecology

Gorilla Ogo has spread throughout much of Waikiki, where is washes up along the beach after large swells.

Gorilla Ogo is extremely adaptable to changing light and salinity, making it very successful in varying conditions. The alga is brittle and easily breaks, so can spread quickly by fragmentation. Gorilla Ogo’s three dimensional growth form allows it to grow over the top of other benthic organisms, including native algae, corals and other invertebrates, enabling it to be
particularly disruptive and ecologically dominant in some habitats.  Gorilla Ogo is very successful in calm, protected waters. It has spread over 5 kilometers from its point of introduction on Oah‘u since it was introduced in 1978. This alien alga started off sterile in Hawaiian waters, but has been found to propagate sexually as well as asexually. Its widespread dispersal is accomplished primarily through fragmentation.

Gorilla Ogo has been present for several decades inside and outside the break wall and in Kapoho Bay in the Hilo area on the Big Island of Hawai‘i; the origin of these populations is unknown. Gorilla Ogo was intentionally transported from Hawai‘i Island to Kane‘ohe Bay and Waikiki in O‘ahu in the 1970’s and later to near Pukoo, Moloka‘i, where it was planted in open reef cultures for experimental aquaculture and research.  It has now taken over the Moloka‘i fishponds and continual removal has been necessary to continue to use the fishponds.

Evidence suggests that Gorilla Ogo has significantly altered benthic community structure and species diversity where it has spread throughout much of Waikiki, and reports suggest that it is now common on much of Moloka‘i’s south shore from Kamalo to Kaunakakai.

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