SECTION 1
ExecutiveSummary               Información español
StrategyPaper                        Fundación La Salle

SECTION 2
Choluteca Declaration by Greenpeace                               Choluteca Declaration         Declaración de Choluteca Deforestación (SP)       Fertilizer research                    Letter to Greenpeace     

SECTION 3
FlasaAgreement (SP)            Contact:

SECTION 4                          
Acuicultura                             Closed System                      Future Opportunities            SobreChitin

SECTION 5                           Tax papers are all in Spanish:                Exoneración                     Seniat     
 

SECTION 6                                All PDF Files:     AboutShrimp                      Acuicultura                          Choluteca Declaration by Greenpeace                                 CholutecaDeclaration              Closed System                        Contact                    Declaración de Choluteca        Deforestación(SP)        Executive Summary             Exoneración(SP)                  FertilizerResearch FlasaAgreement(SP)  Fundación La Salle                  FutureOpportunities            InformaciónEspañol             Seniat(SP)                           Shrimp by Greenpeace
SobreChitin(SP)                        ResumenFertilizante(SP)     Letter to Greenpeace

  
FREEBIES PAGE                                                                                                                           EVVEN did not edited anything

Factors Affecting Production

Introduction:                                                                                                    Shrimp farming, the production of marine shrimp in impoundments,
ponds, raceways and tanks, got rolling in the early 1970s, and, today, over
fifty countries export farmed shrimp. In Ecuador and Brazil, the leading
producers in the Western Hemisphere, export revenues surpass $200 million a
year. In Thailand, the leader in the Eastern Hemisphere, they have passed the
billion dollar mark, and probably would have hit the two billion dollar mark
this year–if prices had not tanked. India, Indonesia, China, Malaysia,
Taiwan, Bangladesh, Sri Lanka, The Philippines, Vietnam, Australia and Myanmar
(Burma) have shrimp farms, and there are shrimp farms throughout Central and
South America. Honduras, Panama, Belize and Mexico have big industries, while
smaller industries exist in Colombia, Guatemala, Venezuela, Nicaragua and
Peru.

The shrimp importing nations–the United States, Western Europe and
Japan–specialize in high-tech "intensive" (more below) shrimp farming, but,
thus far, their production has been insignificant. Many countries in the
Middle East have shrimp farms, with Iran apparently the leading producer in
the region.
Shrimp farms use a one-phase or two-phase production cycle. With the
two-phase cycle, they stock juvenile shrimp in nursery ponds and then, several
weeks later, transfer them to growout ponds. With the one-phase cycle, the
nursery ponds are eliminated, and the shrimp are stocked directly into growout
ponds, after having spent a short period in an acclimation tank (more below).
Farms usually produce two crops a year, although farms within 10 degrees of
the equator sometimes get 3 crops a year.

Hatchery
With the exception the United States and much of Latin America, the world's
shrimp farmers rely on wild shrimp for the production of seedstock. They
capture wild postlarvae, which are stocked into nursery or growout ponds, or
they spawn wild females at a hatchery. Spawning requires raising young shrimp
through several larval and postlarval stages.
Hatcheries sell two products: nauplii (tiny, newly hatched, first stage
larvae) for about $0.50 to $2.00 per million and postlarvae (larvae which have
passed through three larval stages) for $2 to $20 per thousand. Nauplii are
sold to specialized hatcheries which grow them to the postlarval stage.
Postlarvae production costs range from $2 to $10 per thousand.
The Hatchery Cycle:Whether gravid (ready-to-spawn) shrimp are captured in the
wild or matured in the hatchery, they invariably spawn in the dark, so through
photoperiod manipulation, they can be induced to spawn at any time. Depending
on a number of variables (temperature, species, size, wild/captive and number
of times previously spawned), they produce between 50,000 and 1,000,000 eggs.
After one day, the eggs hatch into nauplii, the first larval stage. Nauplii,
looking more like tiny aquatic spiders than shrimp, feed on their egg-yoke
reserves for a couple of days. They then metamorphose into zoeae, the second
larval stage, which have feathery appendages and elongated bodies but few
adult shrimp characteristics. Zoeae feed on algae and a variety of formulated
feeds for three to five days and then metamorphose into myses, the third and
final larval stage. Myses have many of the characteristics of adult shrimp,
like segmented bodies, eyestalks and shrimp-like tails. They feed on algae,
formulated feeds and zooplankton. This stage lasts another three or four
days, and then the myses metamorphose into postlarvae. Postlarvae look like
adult shrimp and feed on zooplankton, detritus and commercial feeds.
Farmers refer to postlarvae as "PLs", and as each day passes, the stages are easier to work with than P. monodon (the most popular species in the
Eastern Hemisphere), captive breeding is more common in the west than the
east. Some of the breeding facilities recirculate the water in the tanks,
creating a closed system where water quality variables can be controlled and
external factors limited.
Hatchery Feeds: Hatcheries utilize a combination of live feeds, such as
microalgae and brine shrimp nauplii (Artemia), with one or a number of
prepared diets, either purchased commercially or prepared at the hatchery.
The principal algal species employed are Skeletonema, Chaetoceros,
Tetraselmis, Chlorella and Isochrysis. Again, dry formulated feeds are
popular, but they don't work on a 100% replacement basis.
In the April 2000 issue of the Global Aquaculture Advocate researchers from
Belgium and Ecuador discussed dry artificial diets for penaeid shrimp
broodstock.

They said:
We recently conducted a survey on the use of commercial diets in shrimp
hatcheries with maturation facilities. The survey included 13 hatcheries in
Ecuador, 2 in Mexico, 3 in the USA, and 1 each in Colombia and Brazil.
Eighty percent of the hatcheries surveyed used some artificial broodstock
diets. In 15% of the hatcheries, artificial diets represented more than 25%
of the total feeding regime. Hatcheries used Breed S (INVE Aquaculture NV,
Belgium), Higashimaru (Higashimaru Co., Japan), MadMac–MS (Aquafauna
Biomarine, Inc., USA), Nippai (Japan), Rangen (Rangen, Inc., USA) and Zeigler
(Zeigler Bros., Inc., USA). One hatchery had its own diet made by a feed
manufacturer. The most popular diet was a dry premix because it allowed
mixing with other nutrients, minced fresh food and medications.
Preliminary results of our joint research effort were presented last year at
the 5th Ecuadorian Aquaculture Conference in Guayaquil (October 1999). We
found that an experimental dry diet could replace 50% of the fresh food in
hatchery diets without loss of reproductive output or larval quality. We also
found that Artemia meal (freeze-dried Artemia biomass) in the diet formulation
improved diet ingestion rate, ovarian maturation and fecundity.
Artificial dry diets for shrimp broodstock offer many advantages, but they are
still not effective in completely replacing fresh foods. A survey of
commercial shrimp maturation facilities indicated that dry maturation diets
are widely utilized, but they comprise only a minor share of the total feeding
regime. Information: Roeland Wouters and Pactrick Sorgeloos, Laboratory of
Aquaculture and Artemia Reference Center, University of Ghent, Rozier 44,
B-9000, Gent, Belgium; and                                                                                    Julia Nieto, CENAIM-ESPOL Foundation,                                                              P.O. Box 0901-4519, Guayaquil, Ecuador.

Hatchery Trends: In the Western Hemisphere, hatcheries are usually very large
and may be associated with big farms. They frequently supply nauplii to
smaller hatcheries in other regions and other countries. The smaller
hatcheries raise the nauplii to postlarvae, which are sold to farms for
stocking in nursery or growout ponds. Many of the large centralized
hatcheries breed shrimp for special characteristics, like rapid growth and
disease resistance.
In the United States, specific pathogen-free (SPF) seedstock has demonstrated
great potential. Prior to the arrival of the Taura virus in 1995, industry
production doubled when the SPF stocks were introduced. Unfortunately, the
SPF stocks of P. vannamei were extremely sensitive to Taura, and the U. S.
industry suffered major losses in 1995. In the Eastern Hemisphere, small and medium-scale hatcheries continue to produce most of the seedstock. Worldwide, the once clear distinction between Japanese/Taiwanese-style and Galveston-style hatcheries is increasingly blurred as a large number of hybrid operations, borrowing the best from both, are adapted to local conditions and experience. The advent of the backyard hatchery has further blurred the distinction. Success has not been the
exclusive domain of any one style, and it is becoming more and more obvious
that hatcheries must be adapted to local conditions.
New Research: On October 4, 2001, Dr. Shea Tuberty, a crustacean
endocrinologist at the University of West Florida, USA, posted this item to
The Crust-L List, a mailing list for crustacean scientists:
"A newly published paper entitled 'Phytoecdysteroids: Biological Aspects' by
Laurence Dinan in Phytochemistry (V-57, N-3 P-325) may be of particular
interest if you are looking for the structure/identity of the 200+
phytoecdysteroids from which crustaceans form their molting hormones."
Information: Shea R. Tuberty, University of West Florida, Center for
Environmental Diagnostics and Bioremediation, One Sabine Island Drive, Gulf
Breeze, Florida 32561 USA (phone 850-934-2431, fax 850-934-9201, email
tuberty.shea@epa.gov ).

New Product: On October 15, 2001, Electronical Larviculture Newsletter,
reported: Intervet has launched the world's first commercial multivalent
vaccine against the major pathogenic Vibrio species in shrimp, including
luminescent bacteria. The vaccine, NorvaxShrimpVib®, is incorporated into
second stage Artemia nauplii, which are then fed to the juvenile shrimp.
Field trials performed in Asia and South America have shown that the vaccine
significantly improves growth and survival. Information: Intervet
International, Aquatic Animal Health Division, P.O. Box 31, 5830 AA Boxmeer,
The Netherlands (phone 31-465-587-600, fax 31-485-577-333, email
info@intervet.com , webpage www.intervet.com ).

Nursery
The nursery phase of shrimp farming, when postlarvae are cultured at high
densities in small earthen ponds or in inclosures within the growout ponds,
occurs between the hatchery and growout phases. Since hatchery-produced and
wild-caught postlarvae can be stocked directly into growout ponds, the nursery
phase is not always necessary. Many farms in the Western Hemisphere now use
acclimation tanks and raceways (more below) instead of nursery ponds.
Farmers stock postlarvae in nursery ponds (0.5 to 5.0 hectares) at densities
of 150 to 200 per square meter and feed a crumbled diet several times a day.
Protein levels in these feeds range from 30 to 45%. The nursery phase should
not exceed 25 days.
Proponents of nurseries argue that they improve inventory, predator and
competition control; increase size uniformity at final harvest; better utilize
farm infrastructure; permit more crops per year; improve risk management;
produce stronger postlarvae; and decrease feed waste. Because low salinity
levels can be lethal to postlarvae, nurseries also provide a halfway house
where salinities can be adjusted to pond levels.
The main criticism of nursery systems is that postlarvae suffer mortalities
when they are transfered to growout ponds. Spontaneous mortalities also occur
in nursery ponds when animals are held beyond 25 days.
Acclimation Tanks: In the Western Hemisphere, acclimation tanks and raceways
are replacing earthen nursery ponds, mostly because tanks and raceways provide
more flexibility. Since they're on top of the pond banks, or higher, it's
easier to transfer seedstock to the ponds. They make it easy to observe and
evaluate incoming seedstock, which can be fed special diets to prepare them
for the rigors of pond life. They make great holding facilities while ponds
are being harvested, or while a storm passes overhead. They give the
seedstock a chance to adjust to pond conditions, particularly salinity and
temperature before stocking. And they don't have to be next to the ponds.
For example, they can be on the hatchery grounds where it's easier to control
water quality and feeding. Nurseries in greenhouses find applications in
temperate climates where it is important to get a jump on the growout season.
The most important consideration during acclimation is that the water quality
parameters be changed slowly. Acclimation densities should not exceed 300-500
postlarvae per liter, depending on animal size and duration of acclimation.
                                                                                                                  Growout
Once a growout operation is stocked with postlarval shrimp, it takes from
three to six months to produce a crop of market-sized shrimp. Northern China,
the United States and Northern Mexico produce one crop per year, semi-tropical
countries produce two crops per year, while farms closer to the equator have
produced three crops a year, but rarely. Temperature has a lot to do with it.
Shrimp like it hot, and most species prefer, but are not restricted to, brackish water.
Growout operations come in all shapes and sizes. They are classified by
stocking densities (the number of seedstock per hectare) and called
"extensive" (low stocking density), "semi-intensive" (medium stocking
density), "intensive" (high stocking density) and "super-intensive" (higest
stocking density). As densities increase, the farms get smaller, the
technology gets more sophisticated, capital costs go up and production per
unit of space increases dramatically.
Extensive: Extensive shrimp farming (low-density) is conducted in the tropics,
in low-lying impoundments along bays and tidal rivers, often in conjunction
with herbivorous fish. Impoundments range in size from a few hectares to over
a hundred hectares. When local waters are known to have high densities of
young shrimp, the farmer opens the gates, impounds the wild shrimp and then
grows them to market size. Fishermen also capture wild postlarvae and sell
them to extensive farmers for stocking. Overall, however, stocking densities
are quite low, not over 25,000 postlarvae per hectare. The tides provide a
water exchange rate of from 0 to 5% per day. Shrimp feed on naturally
occurring organisms, which may be encouraged with organic or chemical
fertilizer. Construction and operating costs are low and so are yields.
Cast-nets and bamboo traps produce harvests of 50 to 500 kilograms (head-on)
per hectare per year. Production costs range from $1.00 to $3.00 per kilogram
of live shrimp. Since it is illegal in many countries to build new shrimp
farms in tidal and mangrove areas, almost no new extensive shrimp farms are
being constructed today.
Semi-Intensive: Conducted above the high tide line, semi-intensive farming
introduces carefully laid out ponds (2 to 30 hectares), feeding and pumping.
Pumps exchange from 0% to 25% of the water a day. With stocking rates ranging
from 100,000 to 300,000 postlarvae per hectare, there is more competition for
the natural food in the pond, so farmers augment production with shrimp feeds.
Construction costs range from $10,000 to $35,000 per hectare. Wild or
hatchery-produced postlarvae are stocked in growout ponds which are fertilized
(nitrogen, phosphorus and silicate) to encourage a natural food chain. The
farmer harvests by draining the pond through a net, or by using a harvest
pump. Yields range from 500 to 5,000 kilograms (head-on) per hectare per
year, with 2,000 kilograms per hectare per year a much sought after goal.
Production costs range from $2.00 to $6.00 per kilogram of live shrimp.
Farmers usually renovate their ponds once a year. If too many semi-intensive
farms concentrate in a small area, they can have a negative effect on the
environment.
Intensive: Intensive shrimp farming introduces small enclosures (0.1 to 1.5
hectares), high stocking densities (more than 300,000 postlarvae per hectare),
around-the-clock management, heavy feeding, waste removal and aeration.
Aeration–the addition of air, or oxygen, to the water–permits much higher
stocking and feeding levels. The water exchange rate can be high, 30% per day
and up. Frequently conducted in small ponds, intensive farming is also
practiced in raceways and tanks, which may be covered or indoors.
Construction costs range from $25,000 to $10,000,000 per hectare.
Sophisticated harvesting techniques and easy pond clean-up after harvest
permit year-round production in tropical climates. Yields of 5,000 to 20,000
kilograms (head-on) per hectare per year are common. Production costs range
from $4.00 to $8.00 per kilogram of live shrimp. It's relatively easy to
convert intensive farms to other species. Intensive farms frequently cause
environmental problems.
Super-Intensive: Super-intensive shrimp farming takes even greater control of
the environment and can produce yields of 20,000 to 100,000 kilograms per
hectare per year! Thailand has some super-intensive shrimp farms. A
super-intensive farm in the United States once produced at the rate of 100,000
kilograms (whole shrimp) per hectare per year, but it was wiped out by a viral
disease. Belize Aquaculture, Ltd., perhaps the most advanced shrimp farm in
the world, uses super-intensive production techniques.
Farming Strategies: Although almost all of the shrimp farms built in the last
few years have been semi-intensive and intensive, much of the world's
production still comes from extensive farms. India, Vietnam, Bangladesh, the
Philippines and Indonesia are good examples of countries with vast areas of
extensive farms. Ecuador and Honduras have extensive farms. China pursues
its own brand of semi-intensive farming in small ponds. Japan, Taiwan and the
United States concentrate on intensive shrimp farming–and intensive farms
occur in all the major shrimp farming areas of the world. If the current
experiments with super-intensive shrimp farming become profitable, the world's
shrimp industries will be changed forever!
Settling Ponds: In an article in the August 2000 issue of the Global
Aquaculture Advocate, Dr. Claude Boyd, water quality expert at Auburn
University, concluded that settling ponds were the best technology for
treating the effluent from shrimp ponds:
Shrimp farmers may think settling basins have to be huge, but they're wrong.
Consider a 500-hectare shrimp farm with 1-meter-deep ponds operated with an
average daily water exchange of 2%. The daily water exchange volume would be
100,000 m3, and on a day when 20 hectares of ponds are completely drained, the
effluent volume would increase to only 300,000 m3 per day. To provide a
detention time of eight hours, a 100,000-m3 settling basin would be necessary.
This would require a 1-meter-deep settling basin of 10 hectares or a
1.5-meter-deep settling basin of 6.67 hectares, representing only 2% and 1.3%
of the farm area.
Even if settling basins are constructed in duplicate and with reserve
capacity, they still would not require more than 4 to 6% of the area of a
large farm. Of course, on a small farm, the proportion of farm area devoted
to settling would have to be much larger, often 10 to 20% of farm area.
Nevertheless, settling basins seem to be the only practical means of treating
effluents from small or large shrimp farms. Information: Claude Boyd, Auburn
University, Department of Fisheries and Allied Aquacultures, Alabama
Agricultural Experiment Station, Auburn University, AL 36849 USA (phone
205-826-4786, email ceboyd@acesag.auburn.edu ).

Mechanized Harvests: In an article in the August 2000 issue of the Global
Aquaculture Advocate, Les Hodgson (owner of Marco Sales, a shrimp
importer/processor), Kieth Gregg (pond manager at Harlinqen Shrimp Farms) and
Robins McIntosh (former farm manager at Belize Aquaculture) discussed
mechanized shrimp harvests. Some excerpts:
There are several types of mechanical harvesting systems, including Archimedes
screw systems, reciprocating vacuum/pressure pumps, and recessed impeller
pumps.The screw system has many advocates because it's simple and easily repaired on the farm. It requires only a small electric motor because it's designed to
elevate shrimp, not water. Pump harvesters require larger motors to move
water and shrimp, but the water-moving capability can be a useful tool. Our
experience has been with recessed impeller pumps, so we will focus on them.
Recessed impeller pumps create a water current that lifts the shrimp to a the
de-watering tower without the impeller blade ever touching the shrimp. These
pumps have been used for for moving tomatoes, live trout and juvenile shrimp.
Recessed impeller pumps are hydraulically driven by a separate electric,
diesel, or gas-powered motor. The pumps are available in submersible and
non-submersible designs. The non-submersible design tends to lose its prime
periodically, which can be problematic during peak harvest periods, so in
Texas and Belize, we use the submersible design.
We prefer to discharge shrimp from the de-watering tower directly into
1-cubic-meter insulated boxes containing an ice slurry . We prefer boxes
without drainage plugs due to the danger of unintentional draining, which can
result in spoilage if the product is stored in boxes for several days.
To minimize the number of workers needed during harvest, boxes are pre-filled
with about 21 inches (53 cm) of ice slurry. Slush ice is ideal for this
purpose. Another option is to pass block ice through a flaking machine and
then add water to create a slurry. If bacteria are a problem, chlorine can be
added to the ice slurry at low levels. For the European market, sodium
bisulfite is added prevent black spots.
Mechanical harvesting systems reduce labor requirements for pond harvesting by
at least 50%. For example, Harlingen Shrimp Farms utilizes six people to
harvest ponds that yield up to 40 tons. This includes a superrvisor, two
workers for the pallet jack, a forklift operator, and two workers operating
the harvest machine.
Information: Les Hodgson, Marco Sales, Inc., P.O. Box 4663, Brownsville, TX
78520 (phone 956-541-4821, fax 956-542-0846, email msshrimp@aol.com); and
Kieth Gregg, Harlingen Shrimp Farms, Ltd., Route 3, Box 300K, Centerline Road,
Los Fresnos, TX 78566 USA (956-233-5723, fax 956-233-9779, email
hsfbayview@compuserve.com ).

Factors Affecting Production

Feeds: As farms evolve from low to high stocking densities, the quality of
feed becomes very important. Most extensive farms (low stocking densities)
don't feed at all; shrimp feed on naturally occurring food organisms in the
pond. Other extensive farms use small amounts of feed and fertilizer to
stimulate the natural food chain. On semi-intensive farms, with many more
shrimp scouring the bottom of the ponds, most of the feed is consumed by the
shrimp and less is available to serve as a stimulant to the natural food web.
Therefore, the quality of the feed is more important because the shrimp get
most of their nutrition from it. On intensive farms, shrimp depend on
commercial diets for most of their nutrients, so intensive farms require the
very best feeds.
Ideally, shrimp in semi-intensive and intensive farms should be fed four or
five times a day, with at least three hours between feedings. High-quality
feeds offer several advantages over lower quality feeds: better feed
conversion, faster growth, lower mortalities and improved water quality. In
1997, feed mills around the world produced approximately one million metric
tons of shrimp feed. All things considered, including the abysmal state of
shrimp farming statistics, that figure probably increased to 1.5 million tons
by 2000.
Feeds can represent over 50% of the production costs on intensive shrimp
farms, and shrimp feed makes a mighty contribution to the sludge on the bottom
of the pond. Consequently, shrimp farmers believe better feeds and feeding
strategies could save them a lot of money. The shrimp's habit of slowly
nibbling feed particles causes substantial nutrient losses even if the pellets
are of good quality. Increasing the water stability of the feed beyond a couple of hours does not help, because leaching of the nutrients will continue, even from pellets showing excellent physical stability. Within an hour, shrimp feed can lose more than 20% of its crude protein, about 50% of its carbohydrates and 85 to 95% of its vitamin content. As much as 77% of the nitrogen and 86% of the phosphorus compounds in shrimp feed are wasted. The waste either accumulates on the pond bottom, or is discharged into the environment. Instead of increasing pellet stability beyond a couple of hours, feeds should include attractants so they are consumed within 20 or 30 minutes. Because the Asian shrimp feed market is highly competitive, most feed manufacturers produce feeds with excessive nutrient levels to assure that
their products are well received in the marketplace. Consequently, shrimp
feeds tend to contain a considerable volume of fishmeal, usually 30 to 35% of
the total. In those countries that produce shrimp extensively–Indonesia,
India, Philippines, Vietnam and Bangladesh–farmers utilize feeds with lower
protein and fishmeal levels.
Farmers in the Western Hemisphere depend almost entirely on dry, commercial
feeds, while 50% of those in the Eastern Hemisphere utilize farm-made feeds
and natural foods, such as trash fish, seafood by-products and various
mollusks and crustaceans, a practice which can encourage the spread of disease
and adds to the organic load in the pond.
Feeding Trays: Most shrimp farmers broadcast feeds from the pond bank or from
small boats. Then they lower feeding trays–small (about 1/2 square meter),
circular or rectangular, mesh-bottomed baskets containing feed–into the pond
to monitor consumption. In 1992, shrimp farmers in Peru began using feeding
trays to feed the entire pond. They distributed the trays around the pond so
that each one "feeds" an area of approximately 500 to 1,000 square meters.
Labor cost are high with this technique. At least two employees are required
for every 10 hectares of ponds. But, because feed conversion ratios are so
much lower when feeding trays are used, labor, construction and equipment
costs are easily covered by reduced feed costs. In addition, feeding trays
offer the following advantages:
• Less pollution and cleaner pond bottoms
• Reduced stress, fewer disease problems and faster growth
• An invaluable source of data on what is going on in the pond
• Early detection of disease
• Controlled administration of medicated feeds
• Reduced pumping and aeration costs
• Less pond maintenance between harvests
• Better harvest estimates
Hand Feeding Versus Mechanical Feeding: The November/December 1999 issue of
Panorama Acuícola contains a great article by René Higuera, technical director
of the Asociación en Participación Atanasia (a shrimp farm in Mexico), on the
advantages and disadvantages of hand and mechanical feeding. Most hand
feeding is done from small, in-pond boats, while mechanical feeding is done
from pickup trucks that cruise the banks.
Advantages of Mechanical Feeding
• The ability to feed 100 hectares of ponds with only three employees
traditional feeding from boats requires one person for every four hectares.
• The cost of the mechanical feeder is actually a little less than the
cost of the two boats and two outboard motors it would take to service 100
hectares.
• Feeding times and the logistics of feeding can be optimized with a
mechanical feeder.
• A pick-up truck can tow the feeder and carry the feed.
• Fuel costs are 50% lower than they are for hand feeding.
Disadvantages of Mechanical Feeding
• Farm roads must be in good condition.
• The dimensions of the pond may affect feeding efficiency. For example,
a mechanical feeder throws feed about 30 meters, and it lands in a band about
5 meters wide, so the center of a large square pond would not receive much
feed.
• Wind may restrict feeding to only one side of the pond.
• Feed may randomly concentrate in certain areas, causing areas of high
organic loading and water quality problems.
• During wet periods, roads often become too slippery for trucks and
mechanical feeders, so the farmer is obligated to feed from canoes.
The Advantages of Hand Feeding
• Feed can be distributed evenly and efficiently in any size pond
regardless of location.
• Competition for feed among shrimp is reduced because the shrimp remain
more distributed throughout the pond (as verified by feeding trays).
• Wind and rain do not interfere with hand feeding as much as they do
with mechanical feeding.
Disadvantages of Hand Feeding
• Efficient supervision is required.
• Labor costs are 12% higher and fuel costs are 50% higher than they are
for mechanical feeding.
• Biosecurity is more of problem as equipment and personnel move from one
pond to the next.
 

Conclusion: Feeding by hand from canoes is less expensive than mechanical
feeding, especially in large, inaccessible ponds where shrimp are grown to
large sizes. In small ponds where shrimp are grown for short periods, the
costs are about the same. Information: René Higuera, Asociación en
Participación Atanasia (phone 64-17-89-97, fax 64-17-89-93, email
atanasia@infosel.net.mx );                                                                                   and Salvador Meza García, Editor, Panorama Acuícola, Allende #823-24,         Plaza el Dorado, C.P. 85000 Cd. Obregón, Sonora, Mexico
(phone 52-64-14-79-15, fax 52-64-13-87-98, email panacua@infosel.net.mx ,
webpage http://www.sea-world.com/panoramacuicola ).
Aeration: Shrimp farmers use tidal flow and diesel pumps to maintain stable
water quality conditions and to renew the dissolved nutrients that sustain
healthy algal blooms in their extensive and semi-intensive ponds. This
process introduces freshly oxygenated water and helps flush out wastes. To
further increase oxygen levels, some semi-intensive farms and most intensive
farms use paddlewheel and aspirating aerators, electrical/mechanical devices
that add oxygen to the water. They are used at night and early in the morning
when oxygen levels are at their lowest. Paddlewheels slap, beat and churn
oxygen into the surface of the water; aspirators inject an oxygen-rich stream
of water below the surface. Shrimp flourish in the currents created by the
aerators.
Paddlewheel aerators have many moving parts and a lot of down time;
aspirators have few moving parts. Producers of paddlewheel and aspirating
aerators actively compete for the intensive shrimp farmer's business. Since
the costs are similar, neither technology has established itself as better
than the other.
Blower-type aerators (low-pressure air), a third technology, deliver air to
the bottom of the pond through a network of pipes and tubes. These simple,
non-mechanical systems can be maintained with unskilled labor. Less popular
than paddlewheels and aspirators, they find applications in hatcheries and in
deep ponds where they break up temperature stratification. Low pressure air
has found many applications in the sewage treatment business and is likely,
over time, to find more applications in shrimp farming. High initial costs
and the need to remove parts of the system prior to harvest limit the use of
low pressure air.
                                                                                                                    Disease:                                                                                                      Diseases represent the biggest obstacle to the future of shrimp
farming. Farms and hatcheries have few defenses against rampaging protozoa,
fungi and bacteria, but it's viral diseases that pose the greatest threat.
They have caused major crashes in Taiwan, China, Indonesia, India, Panama,
Honduras and Ecuador. Currently the Western Hemisphere fights a virus that
arrived from the east (whitespot), and the Eastern Hemisphere fights a virus
that arrived from the west (Taura). There are no medications to treat shrimp
viruses, but management techniques have evolved which lessen their impact.
In Latin America, prior to the arrival of the whitespot virus in 1999, Taura
Syndrome Virus was the biggest killer. Shortly after stocking, it can kill
from 40 to 90% of the postlarvae in a shrimp pond. Although Taura may have
been lurking in the background for years, it officially arrived on the shrimp
farming scene in June 1992, near Guayaquil, Ecuador. It hit several farms,
and then disappeared until March 1993, when it returned as a major epidemic,
killing farm-raised shrimp throughout the Gulf of Guayaquil. Dubbed "Taura
Syndrome" because it was first reported on farms along the Taura River, an
area about 25 kilometers southeast of Guayaquil, it's also called "Little Red
Tail" (La Colita Roja) because the tail fan and body of affected shrimp turn
pale pink. Taura has spread to every country in the Western Hemisphere with
the exception of Venezuela where hatcheries maintain captive broodstock and restrict the introduction of new broodstock. Belize appears to have
eradicated Taura in 1995, only to see it re-appear in 2001. Wild and captive
vannamei appear to be developing some resistance to Taura.
In the Eastern Hemisphere, whitespot virus rages on, but in places like
Thailand, management techniques have brought it under control. Whitespot
usually strikes when the animals have been in the water for more than sixty
days, a critical time for the farmer. He's invested a lot of money in the
crop, but the shrimp are usually too small to harvest. In 1996, whitespot
even attacked extensive farms in West Bengal, India, and the Khulna area of
Bangladesh. Now common in both hemispheres, it's more lethal than Taura,
kills many varieties of crustaceans and has many vectors (carriers).
Fortunately, whitespot is easier to exclude from a farm than Taura because
birds and insects don't appear to be carriers.
Viral attacks in both hemispheres frequently occur after periods of heavy
rain, a stressful time for shrimp, when temperatures, salinities and water
quality variables fluctuate wildly.
Good water quality and lower stocking densities appear to be the best defense
against all diseases. When pathogen populations are low, a shrimp's defenses
are normally capable of preventing disease, but when stressed by questionable
water quality and high stocking densities, shrimp fall prey to "shell-loving"
bacteria, fungi and viruses.
Hatcheries, which maintain concentrated stocks of live feeds and developing
larvae, are particularly susceptible to diseases, which can be introduced with
each new batch of wild broodstock, a known source of pathogens.
Bacteria also pose a significant threat to the future shrimp farming, as
evidenced by the Philippines where Vibrios have cut production by more than
50%. In the July 15, 1999, issue of the journal Aquaculture, researchers in
the United Kingdom discuss some work with Vibrio vaccines. Here's the
abstract of their study: "Significant levels of protection were conferred to
Penaeus indicus larvae for at least 48 hours when either fresh or
freeze-dried Vibrio harveyi vaccines were administered by immersion, but not
when administered orally. The degree of protection increased with the
virulence of the pathogen from which the vaccine was made. Vaccination of
larvae also induced cross-protection against challenge by other V. harveyi
strains." Information: A.O. Alabi, Island Scallops, Ltd., 5552 West Island
Highway, Qualicum Beach, B.C. Canada V9K 2C8 (email islandscallops@bcsupernet.com );                                                                       and D.A. Jones and J.W. Latchford, School of Ocean Sciences, University of Wales, Bangor, Menai Bridge LL57 5EY, UnitedKingdom.
Bird Predation: Migrating flocks of birds can land on a shrimp farm and
quickly consume most of the shrimp. Almost everywhere birds are protected by
law and efforts to scare them away are usually futile. Noise cannons, rockets
and scarecrows work for awhile, but the birds soon learn to ignore them.
Pollution and the Environment: Whenever large numbers of semi-intensive and
intensive shrimp farms concentrate on the same river, estuary or bay, their
rich effluents, primarily shrimp waste products, uneaten feed and dead algae
and bacteria, lower the quality of the surrounding water, overwhelm the
environment and create conditions which favor shrimp pathogens.
Moderate amounts of effluents from shrimp farms have a beneficial effect on
the environment, enriching it without overwhelming it. In some cases shrimp
farm effluent has improved the local fishery. The mangroves and mangrove
species that surround many shrimp farms thrive on moderate amounts of
nutrients from shrimp farms. In turn, the mangroves prevent erosion and
reduce turbidity by trapping sediments and binding nutrients. Ecuador's
extensive shrimp farms operate in a comfortable balance with the mangroves.
In some parts of Thailand, Indonesia and the Philippines, where pollution has
put shrimp farms out of business, mangroves have reclaimed shrimp ponds. In
Thailand, Venezuela and Ecuador, shrimp farmers restore and protect mangrove
areas.
The Weather
The weather plays a major role in the shrimp farmer's life. He never knows
what to expect, but must be ready to alter labor, feeding, pumping, aeration
and harvesting schedules and then be prepared to operate his business from a
boat or plane, while waiting for the restoration of roads, bridges,
electricity and communications. Scheduling hatchery and farm operations at
these times creates major headaches for the industry.
In a very general sense, heavy rainfall and high temperatures benefit shrimp
farming.

The El Niño:
The Monsoon: The southwest monsoon affects the lives of 60% of the world's
population and has a major controlling effect on world food production. India
gets 80% of its annual precipitation from the monsoon, which begins in late
May, when southern trade winds in the Indian Ocean push moist ocean air
northward toward southwest India. When they hit the coast in June, they warm,
rise and shed their moisture. The rising air draws in more cool, moist air,
causing heavy rainfall over most of the country.
The monsoon arrives in Trivandrum, Indian, in June and reaches Bangladesh,
Thailand, China and the Philippines by the end of summer. In September, when
the orbital position of the tilted Earth changes, the wind system reverses,
pulling cool, dry air across Asia and carrying rain to Vietnam, Malaysia,
Thailand, Southeast India, Sri Lanka, Indonesia and Australia, all of which
farm shrimp.
Like El Niño in the western hemisphere, the monsoon flushes out rivers and
estuaries and has a positive effect on shrimp farming and broodstock supplies.
If the rains flood the ponds, however, which frequently happens in West
Bengal, India and Bangladesh—and elsewhere—its effects can be decidedly
negative.
On October 4, 2001, The Indian Meteorological Department (IMD) said that the
country had a normal monsoon in 2001. IMD said cumulative rainfall was 92% of
the long period average, making 2001 the 13th successive normal monsoon year.
IMD said 30 of 35 meteorological subdivisions received normal to excess
rainfall.
Every now and then, however, the monsoon fails, and Indian and Southeast Asia
suffer through endless droughts and baking heat. Agricultural crops fail,
economies slump and governments change. When the monsoon fails during an El
Niño year, someone always speculates that El Niño did it. Events in the 1990s
say they are wrong. El Niño was very active throughtout the 1990s, but there
was not one missed monsoon. Furthermore, the 1997/98 El Niño (April 1997 to
April 1998), the biggest in a century, had no detectable effect on the 1997,
1998 and 1999 monsoons.
Cyclones, Typhoons, Hurricanes and Tropical Storms: Of the major shrimp
farming nations, only Peru, Brazil and Ecuador in the western hemisphere and
Thailand, Malaysia and Indonesia in the eastern hemisphere escape powerful
cyclical storms. These storms are called cyclones in India and Bangladesh,
typhoons in China and the Philippines and hurricanes in the western
hemisphere. It's the huge amounts of rain and the surge of water that
precedes these storms that do the most damage, easily flooding out an entire
shrimp farming region overnight. The wind also tears buildings and hatcheries
apart. These storms hit with enough regularity that shrimp farmers beyond the
safe countries should be prepared to deal with at least one every ten years,
or so. In addition to the physical punishment, they drop enough water to
change the pond chemistry, shocking the shrimp into weakness and often death.
Tropical storms lack the punch of the cyclical storms, but they have a similar
effect on water quality.
For a detailed report on Hurricane Mitch's (1998) effects on shrimp farming in
Nicaragua and Honduras, visit the Shrimp News webpage at
http://www.shrimpnews.com

Conclusion
Viral and bacterial diseases in the growout phase of shrimp farming have
become the industry's biggest problem, but hatcheries are still the weakest
link in the production cycle. Fluctuations in the availability of wild
broodstock and competition from wild seedstock make hatcheries a risky
business. Also, feeding the various life stages of developing shrimp takes a
major effort, and hatcheries are plagued with management, disease and water
quality problems–but they are constantly improving and constantly increasing
production. Hundreds of researchers in a dozen countries work on unraveling
the mysteries of hatchery production, and thousands of hatcherymen in all the
shrimp farming countries tinker with new techniques, designs and ideas to improve production. When hatcheries become more reliable–and they will–the production of farm-raised shrimp will take another leap forward.
World shrimp farming has grown into a multibillion-dollar giant, creating
hundreds of thousands of jobs and much-needed foreign exchange in many third
world countries.
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