2024 January/February Marina World

ENVIRONMENTAL PRODUCTS & PROJECTS
stony coral colonies or seagrass in the
construction area. Within the Fisher
Island Club marina, marine scientists
identified several hundred healthy ‘urban’
stony coral colonies, ranging from 6in to
3ft (15cm to 1m), growing on the rock
riprap below the fixed docks.
These ‘urban’ corals are the focus
of many researchers, who are trying
to determine how and why the corals,
growing in marina basins, large ports
and industrial areas, are doing so well.
The stony corals found in the resident
marina were particularly hardy and
well-adapted to their environment,
which was remarkable considering
the existing fixed docks decrease light
penetration and the vessel activity
increases water turbidity, both of which
can be harmful to coral colonies.
Coral relocation
To allow for rock riprap removal, the
local permits required all stony corals
greater than 6in (15cm) be detached
from the rock riprap and transplanted to
a suitable off-site location. To relocate
the corals, it was first necessary to find
a nearby recipient site with appropriate
water depth, clarity and substrate
with enough available open space
to reattach the stony corals from the
marina basin. A site with relatively
shallow water, located east of the island
and immediately south of the entrance
to Port of Miami, was selected as the
most suitable location to transplant the
colonies.
Following acquisition of the
appropriate authorisations and permits,
stony corals were harvested from the
riprap substrate and relocated to the
preferred coral recipient site. Coral
colonies were assessed for size, overall
health and growth form. Stony corals
presenting signs of disease, overgrowth
by an invasive boring sponge species
or heavy algae, or with low potential for
survival (e.g. breaking apart into very
small fragments) were not removed.
Boulder relocation
obstacles
Several large colonies of stony corals
ranging from 2 to 3ft (0.6 to 1m) in width
were unable to be successfully removed
from the rock riprap due to their
growth form (vertically on the riprap)
and fragility. For those specimens,
it was determined the entire “coral
boulder” would need to be moved. This
unexpected setback was overcome
through coordination between the
Cummins Cederberg environmental
science team and the marine contractor
selected for the dredging and riprap,
Kearn’s Construction Company,
who faced the challenge of carefully
relocating massively sized boulders
using heavy equipment and support
divers without damaging the coral.
With each coral boulder tagged and
identified by marine scientists, the
Kearns Construction team carefully
lifted the entire coral boulder out of the
marina basin with heavy duty slings
secured by commercial divers and a
long-arm excavator.
“Working hand in hand to coordinate
the coral boulder relocation was
crucial for the success of the corals,”
says Kearns Construction operations
director, Brock Sullivan. “The engineer,
environmental science team, and
us (the contractor) had to be in sync
to make sure there was no delay to
the marina renovation schedule, and
more importantly no harm to the coral
colonies.”
The coral boulders were placed on
a construction barge and transported
within a short period of time to a
designated area on a breakwater
outside the marina basin containing
existing riprap and naturally occurring
corals. The time on barge for these
coral boulders was minimised to reduce
long-term exposure to ambient air and
the potential for the living coral colonies
to dessicate or be exposed to harmful
direct UV radiation.
Final marina construction
Over 450 coral colonies were relocated
from boulders below the fixed docks
in the marina basin. Results from a
The remarkably resilient ‘urban’ corals,
which have been successfully relocated,
grew on the rock riprap below the fixed
docks.
six-month coral monitoring programme
required by the County permit
documented a success rate of over
95%, meaning almost all the relocated
stony corals remained firmly attached
to the seabed, were free from coral
disease and were doing well in their
new environment.
Notably, record high water
temperatures during summer 2023 led
to coral bleaching events throughout
South Florida, and the relocated ‘urban’
corals appeared to fare better than
neighbouring natural corals, as they
were likely conditioned to unfavourable
environments from living in an active
marina basin.
When moving from a fixed to a
floating dock system, challenges are
to be expected. Through coordinated
efforts with the environmental,
regulatory, engineer and contractor
team, we were able to resolve the
basin renovations including coral
relocation and permitting tasks related
to the rock removal and dredging. To
complement the engineering team
and contractor, having an experienced
team of environmental scientists and
regulatory experts played a crucial role
in providing Fisher Island Club with its
resilient marina updates.
Vessels have started to move back
into the completed sections of the new
marina, offering partial marina access
to residents. Construction is expected
to conclude in early 2024.
www.marinaworld.com – January/February 2024
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