Caribbean Compass Yachting Magazine - May/June 2022

— Continued from previous page
Watch for New Invasive Coral
The invasive coral Unomia stolonifera has reportedly
spread throughout Venezuela’s Morrocoy National
Park and Mochima National Park, putting their
ecosystems at risk.
The Indo-Pacific octocoral has been reported as a
successful invasive species of the Venezuelan coral
reefs. Since its first appearance there, it has dispersed
along the shallow reefs, overgrowing corals and
seagrass. Surveys revealed that Unomia stolonifera
dominated all studied sites, featuring an average
percentage cover of 30 to 80 percent, far above that of
the native corals.
Native to Indonesia, Unomia stolonifera was
introduced into northeastern Venezuela, possibly via
the illegal aquarium trade, between 2000 and 2005
and had not been registered in any other location of
Venezuela or in the Caribbean Sea until recently.
Since its initial discovery it has rapidly spread.
Dispersal of this invasive has been intensified by
drifting colonies, by colonies settled on detached
seagrass fragments and by colonies entangled on fish
nets and consequently translocated. This intensifying
invasion is causing severe ecological damage to the
Venezuelan reefs. The spread of Unomia stolonifera in
places where it has become established while displacing
native species leads to a decrease in diversity of the
seafloor-dwelling communities.
It seems that Unomia stolonifera is equally capable of
successfully colonizing stony reefs, soft substrates and
seagrass beds. Stony corals are vital for the survival of
a variety of organisms while, similarly, the seagrass
meadows constitute a food source, refuge site, and
breeding and nursery grounds for diverse life forms.
Consequently, it is apparent that this invasive
octocoral constitutes a source of harm to benthic
organisms and fishes, negatively impacting their living
space and food sources.
It should be noted that most of the sites colonized by
the invasive species have also been subjected to prolonged
anthropogenic disturbances, such as both land-based
and coastal activities as well as overfishing. The invasive
soft coral is therefore not the only cause of deterioration
in the recipient ecosystem, but it has nonetheless
become a determinant factor in weakening this
ecosystem’s resilience and stability. A lack of natural
predators also favors the success of Unomia stolonifera.
“Approximately 50 to 60 percent of the coral reef of
the Mochima National Park has been invaded,” warns
Sybil Sant, marine biologist and professor at the
Universidad de Oriente. “The consequence is fatal, it is
killing all the species that make up a coral reef. We are
trying to see, to study, what kind of antidotes can be
used. For that we need research projects, for that we
need funding,”
Fishermen in the area say they first saw this species
a decade ago, but in recent years they have noted how
voraciously it has expanded. José Gregorio Jiménez, a
fisherman who has worked for 34 years on the island
of Arapo, in Mochima, cast his hook to show what the
species looks like: gelatinous, similar to an algae, with
a white body and dark brown tints. For Jiménez, the
advance of unomia has had economic consequences.
His income depends on the sales of the varieties of fish
that have moved away due to the invasion.
Readers are urged to be alert to the appearance of
Unomia stolonifera in other regions of the Caribbean.
Since the invaded sites are adjacent to international
trade ports (Guanta and Guaraguao) it is likely that
the larvae will be transported in ballast water and even
small colonies might attach to a vessel’s hull and
become dispersed to other regions.
Visit www.researchgate.net/publication/351854325
for more information.
Below: Be on the lookout for this invasive,
reef-killing coral. If seen, report to the nearest
Fisheries Department or the Gulf & Caribbean Fisheries
Institute at www.gcfi.org.
REEFBUILDERS.COM
MAY/JUNE 2022 CARIBBEAN COMPASS PAGE 11