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Mote’s earth-friendly fish farm is about to get even greener
— a large-scale project is getting under way this week that will begin
using
solid fish waste to grow saltwater plants for restoration projects.
The project is designed to be a model of how saltwater fish
farms can cost-effectively recycle all of their waste — a goal
commercial-scale
aquaculture has yet to achieve. The move is a key step forward for
sustainable
aquaculture at Mote.
The project builds on Mote’s longstanding efforts at Mote Aquaculture
Research
Park (MAP), which raises saltwater
fish more than 17 miles inland using 100-percent recirculated water.
This
process releases no waste into the oceans, but until now has produced
some dry
solid waste that had to be disposed of on land.
Growing plants to clean water from aquaculture is a
centuries-old technique. In fact, Mote has been growing wetland plants
at MAP
since 2006. But the water used to grow those plants comes from Mote’s
freshwater sturgeon production facility.
Since Mote’s saltwater systems re-use 100 percent of the
aquaculture water from snook and pompano studies, there is no water
discharged. Instead, in this expanded
program, Mote will use the solids.
By using this waste to feed saltwater plants – and doing it
on a large enough scale to translate to commercial operations – this
innovative
system could serve as a model for sustainable marine aquaculture efforts
across
the nation and beyond.
“For years, Mote has developed recirculating aquaculture technology to
reduce
the environmental impact of producing seafood – but there’s still is an
impact
if you can’t use the solid waste,” said Dr. Kevan Main, Director of
Mote’s
Center for Aquaculture Research and Development and leader of the
project.
“When I show people around Mote’s facility and point out that the
saltwater is
completely recirculated, some observant person will ask, ‘Where do the
solids
go?’ Now we’ll be using them up to grow plants for coastal
environments.”
The project, led by Mote scientists and funded through the
National Oceanic and Atmospheric Administration’s Sea Grant program, is
part of
a 2-year study with partners from Aquatic Plants of Florida, Inc., a
Sarasota
business that grows plants for environmental restoration, the University
of
South Florida, Auburn University in Alabama and Aqua Green a private
aquaculture company in Mississippi.
“Totally closed saltwater systems have been examined on an
experimental basis, but to our knowledge they haven’t been done at this
scale,”
Main said.
“We have a full production unit capable of producing 40,000 fingerling
[juvenile] fish and their waste will feed nearly 110,000 plants.”
The waste will come from facilities used to grow Florida pompano,
a
popular sport fish that is currently bred, hatched and raised at MAP.
The pompano waste will feed two large tanks in a greenhouse stocked with
three
plant species: black needle rush, red mangrove and smooth cordgrass.
All three are commonly used by local, state
and federal governments to restore coastal environments after impacts
such as
hurricanes, oil spills and other environmental disasters.
Another part of this project, led by Auburn University
and Aqua Green, will involve recycling pompano waste in a different
process and
using it to grow three types of algae that produce agar and carageenan —
substances used as food additives, including in many products on grocery
store
shelves.
The plants from Mote will be sold for environmental
restoration projects by staff at Aquatic Plants of Florida, who started
producing and distributing freshwater plants through a research
partnership with
Mote in 2006.
The plants will be grown mainly for Florida
restoration projects, but some smooth cordgrass will be stock from
Louisiana. That cordgrass could, in time, be used to
mitigate damages from the Deepwater Horizon oil spill, if cordgrass
harmed by
the spill does not rebound on its own. Cordgrass is a major component of
estuaries, providing habitats for coastal and marine wildlife and, in
the case
of the spill, it also kept oil from reaching many plant species closer
to dry
land.
For the current project, the partners aim to produce one crop of
saltwater
plants in spring 2011 and another in summer.
“The species of plants we’re using and the way we’re growing
them is designed to fit with restoration projects,” said Gil Sharell,
founder
and president of Aquatic Plants of Florida. “We’ve already had success
with
producing freshwater plants at Mote for restoration. It seems like
natural
progression to go from fresh to salt.”
Scientists at USF and Mote will evaluate how efficiently the
plants take up nitrogen and phosphorous, chemicals in the fish waste
that
plants need to grow.
Project partners will evaluate the costs and benefits of
this new system for producing pompano as well as beneficial plants, to
compare
the economics of this system with current industry practices.
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