| In the Florida Everglades south of Lake Okeechobee, a
new kind of shrimp farming company has opened for business.
Although it's located 60 miles from the ocean, OceanBoy
Farms Inc. raises saltwater shrimp. The tasty crustaceans
hatch and grow in pristine water pumped from a subterranean
aquifer into a complex system of pipes and lined ponds. In
this closed ecosystem, carefully managed with respect to alkalinity
and nutrient levels, the shrimp flourish in a harmonious and
mutually beneficial relationship with natural aquatic bacteria
and indigenous plants.
OceanBoy is the largest US shrimp producer to receive USDA
organic certification. During the latter half of 2005, the
firm harvested, processed, and packaged more than 1.2 million
pounds of organic shrimp—all without a drop of wastewater
leaving its property.
The enormity of this achievement contrasts with the environmental
mayhem wrought by other pathways a shrimp may travel to reach
your mouth.
"In the past 50 years, coastal shrimp farming has
shared a great deal of the responsibility for destroying naturally
growing mangroves along beaches worldwide, either by cutting
them down to build shrimp ponds or by polluting or otherwise
devastating their habitat, while ships fishing for wild shrimp
destroyed reefs and sea-grass beds," explains David
Z. McMahon, OceanBoy's founder and chief science officer.
Bycatch and Antibiotics
Another issue with wild-caught shrimp is that of trawling's
impact on fish and other sea creatures. For every pound of
shrimp a trawler captures, it also nets seven pounds of bycatch
(fish and other sea creatures) that are cast back into the
water to die. In Asia, where shrimp fishermen aren't
required to use nets with turtle escape devices, trawling
activities lead to the death of an estimated 150,000 endangered
sea turtles each year.
Mangrove forests and their adjacent estuarine waters are
among the world's most productive and biodiverse wetlands,
serving as nurseries for most ocean fish. Coastal shrimp farming
has destroyed an estimated 800,000 hectares (more than 3,000
square miles) of mangrove forests worldwide—an area
larger than the states of Delaware and Rhode Island combined.
In addition to mangrove destruction and the resulting sediment
runoff, discharges of nutrient-rich water from coastal shrimp
ponds can promote destructive algae blooms. Moreover, many
foreign countries feed antibiotics to their pond-raised shrimp
to combat white spot virus and other diseases of crustaceans
raised in dense concentrations in a seawater habitat. Consumers
could be ingesting residues of potentially harmful drugs in
some foreign shrimp.
Sara Graslund of the Institute of Applied Environmental
Research in Stockholm, Sweden, says organotin compounds, copper
compounds, and other compounds with high affinities for sediments
leave persistent, toxic residues and are likely to have a
negative impact. In addition, she says certain antibiotics
used to combat shrimp diseases "pose a risk of danger
toward human health."
In April 2005, the USDA directed its field personnel to
detain shipments of shrimp from 13 firms in China, India,
Malaysia, Peru, Venezuela, Thailand, and Vietnam because the
shrimp contained chloramphenicol, a potent antibiotic. It
is banned from food in the US because it can cause bone marrow
depression leading to aplastic anemia and other potentially
fatal blood disorders, as well as blurred vision and inflammation
of the optic nerve.
Deep Wells
OceanBoy owns more than 2,500 acres at two separate locations
in Florida: La Belle Farm, four miles south of LaBelle, and
Little Cypress Farm near Clewiston. The firm has 133 acres
of shrimp production ponds: 17 ponds, each with a capacity
of 4.5 million gallons, on 38 acres at LaBelle Farm; and 24
ponds, each with a capacity of 7.5 million gallons, on 95
acres at Little Cypress Farm. The ponds average 6 feet in
depth and hold a total of 256.5 million gallons of water.
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| A pond is lined with HDPE during construction. |
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| Paddle-wheel aerators patrol a treatment pond. |
The remainder of the acreage consists of expansion space
for additional production ponds, some natural wetlands that
must be preserved to comply with state law, and artificial
water-treatment ponds through which water circulates en route
back to the production ponds.
In these treatment ponds, native vegetation—including
potted white and black mangrove trees—helps to maintain
the purity of the water. Beginning in the fall of 2003, OceanBoy
established a nursery for 10,000 mangrove seedlings in these
ponds. They were brought to the farm and sanitized with hydrogen
peroxide for biosecurity. As they grew, OceanBoy donated some
of the mangrove plants to replenish natural habitat elsewhere
in Florida.
By 2008, the firm expects to own more than 7,000 acres in
the Clewiston area and elsewhere in south-central Florida,
and to operate more than 600 production ponds, reports Michael
Mogollon, OceanBoy's senior vice president of science
and technology.
The water in OceanBoy's ponds originates as groundwater,
pumped from six artesian wells (two at LaBelle Farm and four
at Little Cypress Farm). They tap the Floridan Aquifer at
a depth of 1,000 feet. To extract the water, OceanBoy uses
Model N260 pumps from National Pump Company LLC, of Peoria,
AZ. Each pump can extract 800 gallons per minute, so the total
pumping capacity is 1,600 gallons per minute at LaBelle Farm
and 3,200 gallons per minute at Little Cypress Farm.
The piping at each location consists of 15,000 linear feet
of A-2000 corrugated PVC pipe from Containment Technology
Inc., of St. Gabriel, LA. The LaBelle Farm layout employs
6-inch and 10-inch pipes and requires circuitous piping; Little
Cypress Farm is larger but employs 12-inch pipe in a more
efficient design. "We refined the layout at Little Cypress
Farm," Mogollon says. "We learned to do it with
bigger pipe and fewer feet."
Most of the aquifer's lateral flow comes from the
pressure originating in Lake Okeechobee, though vertical flow
and horizontal flow from other sources also contribute to
its volume. "There is no contamination in this water,"
Mogollon says. "It is virgin groundwater, thousands
of years old, so it contains no pesticides, insecticides,
or artificial chemicals."
Floridan Aquifer water is brackish, hard, and alkaline.
It has a salinity of three parts per thousand (compared to
35 parts per thousand in full-strength seawater), contains
400 ppm of calcium and magnesium that dissolved as the water
leached through layers of limestone above the aquifer, and
has a total alkalinity (the sum of all the chemical bases
in the water) of 160 to 180 ppm.
Evaporation and Rainfall
OceanBoy's ponds are lined with HDPE (high-density polyethylene).
"After eight hurricanes and no damage to the ponds,
I would say it is extremely secure," Mogollon says.
"We check for small breaks in the liner at the beginning
of each new production cycle when we empty the ponds one by
one. Any holes or rips are heat-welded with special extrusion
heat welders."
The ponds lose two to three inches of water a day to evaporation,
thanks to summer heat and to paddle-wheel aerators that splash
water into the air. Makeup water comes from the wells, and
from rain. In an average year, the Clewiston area receives
about 50 inches of rainfall, concentrated primarily in the
summer months.
OceanBoy has samples of its pond water and well water analyzed
at regular intervals by Eurofins Scientific Inc., the Memphis,
TN-based US arm of an international bioanalytical services
group with operations in 15 countries. "The results
of these analyses demonstrate that we don't have contaminants
in our water," Mogollon says. "There is nothing
to purify out of the water. Once it enters the production
ponds, it is confined in our closed ecosystem. We use it and
reuse it and reuse it."
Balancing the Ecosystem
A traditional shrimp farm confronting an imbalance in water
quality in its production ponds would solve the problem by
replacing up to 50% of their water. OceanBoy's zero-discharge,
zero-exchange approach entails maintaining a balanced ecosystem
in its shrimp ponds by simultaneously managing the shrimp
growing in the ponds, bacterial populations coexisting with
the shrimp, and the chemical and physical water-quality parameters
required for optimal growth by shrimp and bacteria alike.
These include an adequate oxygen level (measured by dissolved
oxygen and biological oxygen demand) and proper pH. Neutral
pH is 7; natural seawater is slightly alkaline, with a pH
of 8.3. "Shrimp like their pH in the eight-ish range,"
Mogollon says.
The shrimp eat an organic high-protein feed containing specific
amino acids that fulfill their nutritional requirements, with
a different formulation for each life stage. The feed contains
fish meal for some critical amino acids not contained in vegetable
protein, plus soybean meal, wheat, vitamins, and minerals.
It has no antibiotics, chemicals, hormones, pesticides, preservatives,
or other additives.
Some of the bacteria in the shrimp ponds digest the solid
wastes that the shrimp produce. Other bacteria engage in nitrification,
converting ammonia from the soluble portion of shrimp excretions
to nitrite and then to nitrate. In this process, the ammonia
loses hydrogen ions and gains oxygen atoms, while consuming
alkalinity. "In aquaculture, it's favorable to
start with water that has high alkalinity," Mogollon
says, "so the nitrification that occurs in the ponds
can be carried out effectively."
OceanBoy's installations have no industrial filters;
the ponds themselves are bio-filters. Ponds where nitrification
occurs have AquaMats (Kevlar mats from Meridian Aquatic Technology
LLC, in Beltsville, MD) suspended in the water, providing
a substrate on which the nitrification bacteria grow. OceanBoy
began using AquaMats to control nitrite toxicity but over
time has come to rely on them for total nitrogen metabolism
(ammonia, nitrite, nitrate) and have, in addition, seen significant
phosphorous removal.
The bacteria are 50% protein. As they break down the shrimp
wastes, they grow and aggregate into colonies, called floc,
forming a nutritious particulate that shrimp can pick out
of the water and eat. Thus, the bacteria convert the energy
contained in the shrimp waste back into additional food for
the shrimp.
Mogollon describes these bacteria as "probiotic"
because they participate in an association of two organisms
that enhances the life processes of both. OceanBoy has cultured
some of these probiotic bacteria and inoculated the pond water
with them. Others are freeloaders indigenous to the atmosphere
and the ponds' natural surroundings.
"We encourage the types of probiotic bacteria that
help to break down the shrimp wastes by managing the available
carbon and nitrogen in the water," Mogollon says. "The
nitrogen is in the water from excretions and undigested protein.
These bacteria require a ratio of 15 parts carbon to one part
nitrogen. To guarantee that the bacteria are in an ideal environment
to proliferate, we add organic carbon to the water to attain
that ratio."
The organic carbon comes from sugars in molasses added to
the shrimp feed. A commodity readily available from local
sugar mills in the Clewiston area, the molasses is about 50%
sugars.
Tight Biosecurity
OceanBoy's shrimp are certified specific pathogen free
(SPF), which means they don't harbor diseases fatal
to shrimp. To keep its shrimp disease-free, the company has
instituted a strict biosecurity protocol.
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| OceanBoy Farms grows mangroves in a nursery. The mangroves are used in water treatment. |
Visitors are allowed on the farms only by appointment and
with a company escort. All who enter must wash their shoes
in a footbath at the entrance to the main office, enter the
office, wash their hands with antibacterial soap, and then
pass through a second footbath at the exit of the main office
before entering the production area. Visitors who have been
to another shrimp farm within the last 30 days must wear special
disposable jumpsuits and footwear. Vehicles entering the farms
must drive through a chlorine tire bath.
No seafood may be brought onto the farms, and the entry
of equipment, vehicles, materials, or people coming from an
area where shrimp are caught, handled, processed, or sold
is prohibited.
Shrimp Life Cycle
Newborn shrimp emerge from their eggs as larvae, which undergo
a 20-day series of transformations into nauplii, protozoeiae,
myses, and then post-larvae about half an inch long. At the
post-larvae stage, they are transferred from the hatchery
to a nursery, where they spend the next month growing into
juveniles.
At seven weeks of age, the juvenile shrimp are transferred
again, into ponds where they grow for four months until they
are ready to harvest. Twice a year, July-August and November-December,
the shrimp are harvested and sent on ice from the ponds to
OceanBoy's processing plant in Clewiston. After sorting
by size, some of the shrimp are sold raw; others are cooked,
peeled, and deveined.
Ten percent of the crop is sold fresh. Ninety percent is
cryogenically frozen. The processing plant has an 11,000-gallon
nitrogen tank, an immersion freezer, and an 18-foot, post-cool
freezing tunnel.
Some of the shrimp are sold whole; others have their heads
removed. OceanBoy recycles the heads to produce shrimp flavorings
and protein additives for pet food.
Shrimp are sold according to a count of tails per pound
within a specified range. For example, 41/50 means 41 to 50
tails per pound. OceanBoy's yield follows a bell curve,
with 60% to 70% in the 41/50 and 36/40 categories. Jumbo shrimp—16/20,
21/25, and 26/30—account for 10% to 15% of the crop.
The rest are smaller, primarily 51/60.
OceanBoy distributes its shrimp through a number of supermarket
chains, including Foodtown, Harris Teeter, and Publix; through
food-service distributors Performance Food Group and Food
Innovations/US Foodservice; and online at Costco.com
and FreshDirect.com.
In nature, the Pacific white shrimp (Litopenaeus vannamei)
that OceanBoy raises are spawned offshore in the ocean. When
they become post-larvae, an instinctive migration urge draws
them toward an estuarine habitat to find food and hide from
predators. During this time, they adapt to the lower salinity
of the onshore water. OceanBoy exploits this characteristic
to grow the shrimp in the brackish water of its ponds.
OceanBoy produces its own post-larvae, using brood stock
that are part of the firm's selective breeding program.
Shrimp normally live two or three years. "We keep our
brood stock for a year and a half," Mogollon says. "From
every crop we select animals that exhibit high growth capacity,
reacclimate them to higher salinity in tanks purposely built
just for this so they will reproduce, and grow them for a
year to sexual maturity to become brood stock. Then we keep
them for another six months in the hatchery at Little Cypress
Farm. They become the genesis of the next generation of OceanBoy
shrimp. Doing this crop after crop, we get sustained increments
in the growth rate of the shrimp."
From Concept to Reality
The concept of growing saltwater shrimp in low-salinity, inland
ponds originated with McMahon. "I was determined to
see if there was a way to move an operation away from the
shore and not use marine waters," he says. "So
now we raise marine shrimp inland in artesian freshwater ponds."
Beginning in 1997, McMahon undertook a feasibility study
of sustainable saltwater shrimp production at an inland location
as a dissertation topic for his Ph.D. degree in oceanography
and marine biology at the Nova Southeastern University Oceanographic
Center in Dania Beach, FL.
After conducting geological studies to find the water best
suited for raising shrimp, McMahon selected south-central
Florida and raised money from a group of investors to fund
land acquisition and development of facilities, first in the
LaBelle area and later near Clewiston. OceanBoy Farms harvested
its first crop in 2001 and incorporated in March 2002.
In 2001, McMahon purchased his initial batch of shrimp larvae
from Florida Shrimp Improvement Systems, a hatchery in the
Florida Keys. There he met Mogollon, a respected international
aquaculturist who was FSIS's operations manager. After
working briefly with McMahon and his team to help acclimate
the larvae, Mogollon joined OceanBoy in 2002 to enhance the
firm's efficiency and expand its operations to a commercial
scale.
Mogollon earned a Bachelor of Arts degree in biology from
Harvard University and a Master of Science degree in fisheries
and aquaculture from Auburn University in Alabama. "I
come from a science family," he says. "My father
is a pathologist from Bogota, Colombia; my mother is a bacteriologist
from Boston, MA. I grew up between the United States and Colombia
as my father went from scientific appointment to appointment."
A week after receiving his master's degree in August
of 1985, Mogollon was running a shrimp hatchery in Guayaquil,
Ecuador. "Ecuador was the Mecca of shrimp farming back
then," he says. "Biologists from all over the
world were hired by Ecuadorian firms to develop the science
of shrimp farming husbandry. Hatchery science, in particular,
was developing rapidly as companies switched from wild shrimp
post-larvae to hatchery-reared post-larvae."
Since then he has worked in or consulted for shrimp operations
in Colombia, Panama, Costa Rica, Nicaragua, Guatemala, Belize,
Aruba, Alabama, the Florida Keys, and now south-central Florida.
GEORGE LEPOSKY is a science and technology
writer based in Miami, FL.
OW - January/February 2006 |
