Aquaculture Non-Fish Species

Important Aquaculture Non-Fish Species

Updated May 2015

By Dan Burden, content specialist, AgMRC, Iowa State University, djburden@iastate.edu.; with prior revisions and original contributions from C. Greg Lutz, specialist and professor, LSU Ag Center, glutz@agcenter.lsu.edu.

Alligators

Australian Redclaw Crayfish

Crawfish

Oysters

Shrimp

Turtles

Most non-fish species are not well suited to “closed” recirculating-type aquaculture production systems and tend to be raised in outdoor ponds or net pens.  Shrimp and some crayfish species are exceptions and in well-planned operations may be efficiently and economically raised in indoor recirculating systems.

Alligators

By C. Greg Lutz, Pramod Sambidi and R. Wes Harrison, Louisiana State University (LSU) Agricultural Center.

During the past four decades, production of farmed American alligators (Alligator mississippiensis) for their hides and their meat expanded significantly, even as it shifted to fewer and larger operations. In 1972 a total of 35 farmed skins were sold in Louisiana, compared to an all-time high of 305,176 in 2007.

Louisiana and Florida continue to dominate the industry. The 2011 value of farmed alligator production in Louisiana was estimated at $38.5 million, up from $28.7 million in 2010 (LSU Ag Center 2012). Meanwhile, the net sales of alligator hides and meat in Florida fell from a high of almost $7 million in 2008 to $2.6 million in 2010.

While the number of U.S. farms selling alligator hides has declined, the number of hides sold each year generally increased until exhibiting a steep decline in 2010 and 2011 as a result of low prices and reduced stocking rates in 2008. While the worldwide economic recession was largely to blame for this downturn, some industry observers also cite consolidation within the tanning sector as a downward influence on prices to producers. In either case, the luxury item status of alligator hide products makes them particularly susceptible to market volatility when economic downturns occur. At present, sustainable management programs are being carried out in Louisiana, Florida, Georgia, Texas and South Carolina. Programs include a combination of farming, ranching and direct cropping of wild alligators.

Alligator farming provides producers an opportunity to generate high-valued products year-round for both national and international markets. Compared to other animal industries, it requires small tracts of land and does not have adverse effects on the environment when facilities are properly designed and operated. It also benefits wetland conservation where state agencies permit alligator growers to stock their farm with hatchlings collected from private wetlands, providing the owners of the wetlands some incentive for maintaining them (Lane and King 1996).

The farmed alligator supply chain begins in the marsh with eggs laid by wild females. A portion of these eggs are allowed to be collected based on nest counts, habitat ratings and population censuses. Regulations vary but are generally very strict concerning where, when and how eggs may be collected. Permits for egg collection are issued with the participation of the landowner. Eggs are then incubated under controlled conditions, and hatchlings are sold for grow-out. Access to eggs and hatchlings is a key component of the business plan for any commercial alligator farm. Farmers may establish agreements to collect eggs from private property under the appropriate permits or they may purchase legally taken eggs from collectors. In recent years, a conservative estimate of eggs collected per typical season is approximately 300,000, valued at over $1.8 million.
 
Growers raise their alligators in heated houses to a length of approximately four feet, at which time some portion may be required to be returned to the areas they were originally collected from as eggs, while the rest are humanely slaughtered for hides and meat. It normally takes roughly 15 months for alligators to reach minimum marketable sizes. Once alligators are marketable, they are slaughtered and skinned, but in some cases (such as in Louisiana), not before a pre-designated percentage have been returned to natural habitats to replace those that would have survived in the wild up to that point in time. Hides are prepared for sale and transport by cleaning and salting, while meat is butchered and packaged under sanitary conditions typical of any other meat-packing operation.
 
Upon slaughter, a tag is attached to the hide that will accompany it throughout marketing and tanning until the hide becomes finished leather products. A similar tagging system is used for meat products. At this point in the supply chain, meat can be considered a product, but hides are still more of a commodity.
 
Hides are sold for further processing through a variety of channels. Salted skins are measured and graded by size and quality, and then offered for sale either through open auctions, private auctions or direct private sales. Some portions of these hides are purchased by brokers who store and grade the skins to meet specific buyers’ needs, often on a speculative basis, while other sales increasingly involve purchase directly by tanners.

Once hides have been tanned, the final step of the supply chain involves sales to manufacturers of leather goods such as watchbands, handbags, footwear and fashion accessories. Profitability of industry segments is difficult to quantify, but concentration patterns and producer perceptions over the past several decades suggests most profitability occurs in value-added sectors of the supply chain. This pattern has persisted as consolidation progresses in both production and processing.

Production of farmed American alligators expanded significantly since becoming established in the 1970s. Over the past decade, farms in Louisiana, Florida, Texas, Georgia and Idaho have sold alligator hides. Trends in numbers of operations however, illustrate the shifting of production and marketing to fewer, larger farms. Although highly variable from year to year, the value of farmed alligator hides generally increased from roughly $8 per linear foot in 1972 to $42.50 in 2006. From 2007 onward, hide value has been determined by the width of the belly, with average prices ranging from a low of $5 per centimeter in 2009 to a high of $7.25 in 2007.  The 2013 (2014) Census of Aquaculture had hide prices at $32.66 per linear foot with 644,000 linear feet of material marketed, valued at $21,020,000.  This production originated from twelve farms in Louisiana (9), Florida (2) and Georgia (1)

Alligator meat is an important secondary product for farmers. However, the wholesale value of processed alligator meat in Louisiana has only increased from roughly $3.50 per pound in the 1980s to $4.50 in recent years. Alligator meat is a healthy choice compared to many other products. Farm-raised alligator is low in fat and high in protein. A 4-ounce serving (110 grams) of raw alligator meat contains 24 g of protein, only 2 g of fat, 55 mg of sodium and 55 mg of cholesterol, and provides 110 calories. Industry organizations are taking measures to educate consumers and restaurants with respect to the qualities of alligator meat. Moreover, growers and processors are producing value-added alligator meat products such as sausage and ground patties. (American Alligator, Florida Department of Agriculture and Consumer Services).  The 2013 (2014) Census of Aquaculture had meat prices at $3.94 per pound with 1,151,000 pounds marketed, valued at $4,540,000.  These originated from ten farms in Louisiana (7), Florida (2) and Georgia (1)
 
Usage of farmed alligators has increased steadily, although some variability occurs from year to year as a result of market forces, natural fluctuations in hatchling availability and general economic trends. Usage generally increases or decreases from year to year in response to global economic conditions and fashion trends.  The demand for alligator hides and meat is usually well established in North America, Europe and Asia. All parts of farmed alligators are used for various markets, but skins account for approximately 68 percent of the total wholesale value.
 
Perhaps the largest barrier to entry in alligator farming involves the initial grow-out cycle and associated cash flow requirements. The need to warm make-up water to the appropriate temperature (89 F) after flushing alligator houses comprises a large part of operating costs. Additional barriers to entry involve sourcing hatchlings and feed supplies, locating legitimate buyers, arranging for slaughter and processing of meat and hides, and regulatory requirements (for example, wildlife, zoning, health licensing). Economies of scale also come into play, because very small and very large operations appear to have competitive advantages.
 
Alligator farming is associated with numerous regulatory programs. All alligator farmers and trappers must possess licenses, and all skins must be tagged with serial numbered tags. International trade of alligator skins requires approval and documentation through the CITES Treaty of Wild Fauna and Flora.
 
The following links provide more information on alligator farming regulations:
Louisiana Alligator Regulations (Regulatory Information)
Florida Alligator Farming (Regulatory Information)

From a producer’s standpoint, the alligator farming industry has already evolved to a commodity product market. Although price competition may become a major determinant of market share under certain conditions, prices offered to producers generally reflect international market conditions, and profitability from year to year is determined on a farm-by-farm basis, reflecting production costs.
 
Following several years of growth in the number of farmed alligators produced, the industry has begun to suffer temporary reductions in volume because of shortages of eggs and hatchlings resulting from hurricane damage to nesting habitats. The effects of limited egg collection in Louisiana during 2009 became apparent in 2010 (Outlook for Louisiana Agriculture 2010).

Even more recently, industry expansion has reversed in response to the global economic recession. The industry appears poised for further consolidation, and the long-term effects of changes in the international market structure for hides remain to be seen (Outlook for Louisiana Agriculture 2010).

One of the main problems facing the alligator farming industry is the lack of public awareness, with respect to the wildlife management that forms the basis of the industry. American alligators are still classified as endangered (even though as a species they are not), and this may discourage consumers, who are not aware of the sustainable management programs currently in place, from buying alligator products. Measures must be taken to expand current markets and develop long-term marketing plans in order to increase the demand for alligator products domestically and internationally, thus supporting stronger prices.


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Australian Redclaw Crayfish

By Daniel Burden, AgMRC Content Specialist, Iowa State University; and D. Allen Pattillo, Iowa State Fisheries Extension, NCRAC (North Central Region Aquaculture Center).

The Australian redclaw crayfish (Cherax quadricarinatus) has been proven to be particularly suited to aquaculture and aquaponic production systems.  The red claw was first considered for aquaculture in the 1970s and is quickly becoming an important species for aquaculture worldwide.  Redclaw are valued as both a food source and as an ornamental aquaria species. Aquaculture for the redclaw occurs in Australia, Southeast Asia, Africa, Latin America and to a small extent, the United States.  Considered to be a popular aquaculture crustacean species there is growing interest in using them as an additional animal profit center in aquaponic (fish/plant) systems, due to its potential large size and resemblance to American lobsters.  It is a subtropical species, native to Australia, with relatively high tolerance to poor water quality.  At this time, the redclaw aquaculture industry is essentially undeveloped in the United States due to lack of infrastructure and knowledge of the species; as well as a lack of consumer awareness and related market development.  Using straight-forward production technology the species usually is profitable to produce.

This physically robust species has a simple life-cycle, and requires simple foods.  Production technologies are relatively well developed, and 'best practice' production methods and standard-operating procedures have been defined and are available in the scientific literature.  In many states where escaped redclaws may be considered a potential invasive species, special permit and procedures may be required for aquaculture production.  Producers can start with either juveniles or brood stock.  Both can be purchased from sources in North America.

The species has been well-received by the general public in taste tests and high-value culinary presentations in white-table-cloth restaurants.  Redclaw can grow to considerable size relative to other species and generally are very hardy under properly monitored and maintained conditions.  In one growing season (five to seven months), they will grow to 60 to 120 grams, whereas in comparison, the native North American red-swamp crayfish (Procambarus clarkii), will only reach 28 to 40 grams.  The dress-out percentage (edible tail portion), of the redclaw is considerably higher (30%) than that of the red swamp crayfish (15% to 20%); additionally, similar to crabs and lobsters, large redclaws have considerable claw meat.

Redclaws are scavenging omnivores, and will eat a wide range of scavenged vegetable matter or living animals.  For captive redclaws, the primary diet should include plant matter, worms or insect larvae, and can include vegetable matter waste from aquaponic systems.

The crayfish require dechlorinated water between 80 degrees and 90 degrees Fahrenheit, with a pH of 7.2 to 8.2; although a range of 6.5 to 8.0 also is cited in research literature.  This moderately hard water should contain a fair amount of calcium.  As with almost any aquatic animals within an aquaculture or aquaponic production system, water quality, particularly water chemistry, is critical.  Red claws like most aquatic organisms are highly ammonia intolerant.  Nitrogen spikes from improper filtration, introduction of chlorinated water, or similar poorly monitored water additions can easily kill an entire production-system population.

To deal with ammonia or nitrite (waste byproducts) good biological filtration (as in an aquaponic system), good aeration and water circulation are critical.  Crayfish suffering from ammonia or nitrite toxicity suddenly become listless with little limb movement.  This can be avoided with frequent water testing to ensure that ammonia and nitrite levels are at acceptable concentrations and by designing redundant filtration modules into production systems.

The crayfish is ready to reproduce at about one-year of age.  In southern United States outdoor-pond cultures, the species tends to breed between September and April.  Males deposit sperm on the belly of the female; the female releases 200 to 1000 eggs within 24 hours which are then fertilized by the waiting sperm.  Eggs are then attached to the legs of the female until they hatch roughly 10 weeks later.  Severe disturbance of the female during this period may result in loss of the developing eggs.  One aquaculture-related attribute of redclaw reproduction compared to some other crustaceans species, is the lack of a free-living larval stage and the need of a specialized hatchery and related procedures.

Indoor production tends to have the same general considerations as outdoor pond production.  Abundant artificial shelters for the crayfish are essential.  Redclaws are relatively gregarious and their non-burrowing nature makes them well suited to aquaculture; but some cover to help protect vulnerable soft-exoskeleton individuals during molting cycles is still required.  Shelter design and its positioning within the enclosure should permit water to freely and completely drain and not hinder recovery of the crayfish when the tank or pond is drained.  Thick bundles of plastic mesh and/or stacks of pipe material have been found produce effective cover.

Aeration is essential for any production system.  For tank-production aquaculture or within the growing beds of aquaponic systems, it is most often provided through airlift pumps and airstones.  In pond systems, other forms of aeration such as paddle-wheels and aspirators (where air is pulled into a moving water column) may be more applicable or cost effective.  Combinations of aeration systems can have the added benefit of one being a back-up to the other should one component of the system fail.  The design of any aeration system should provide not only oxygen but promote healthy water circulation within the tank, growing bed or pond.

In outdoor production, pond design is important to minimize establishment and operation costs.  Using gravity to fill and drain ponds; having centralized support facilities; ready and efficient access for personnel, vehicles and mobile tanks; and similar considerations are important to a venture’s efficiency and profitability.  Optimal ponds specifications have been cited in the literature at 1000 square meters (10,764 square feet) of surface area with a depth of 1.2 to 2.5 meters (~13 to 27 square feet).  A bottom design that promotes rapid and complete drainage, complete crayfish population recovery, and the absolute least handling loss is extremely important.

Since feed and labor are the major costs of production in aquaculture systems, it is important to reduce feed inputs and labor to a minimum.  Removing the slower-growing less feed-efficient females and only rearing males can greatly increase the efficiency and profitability of a production system.  Currently, these “monosex” populations are produced by physically separating the sexes by hand sorting; however, this is a time-consuming, laborious process, which needs to be streamlined through hands-on research and innovation. 

The monosex-male culture systems for redclaw are the fastest and most efficient way to grow large crayfish of the highest market value.  Monosex-male culture systems produce larger individuals than mixed-sex cultures because males grow faster than females and, in the absence of females, channel their energy towards growth rather than male-male competition for reproduction and reproductive activity.  In one scientific study, the Australian yabbie crayfish (Cherax albidus), a close relative to the redclaw, when grown in monosex male, monosex female, and polysex cultures, the monosex male culture had a 70% increase in the market value of the final product when compared to the other cultures.  Similar results have been seen in preliminary monosex studies with the redclaw.

Native to Australia, there is concern about the redclaw’s potential invasiveness in North America.  Escaped individuals in Mexico have established some localized breeding populations in ditches and sloughs.  This is highly unlikely in most of the United States due to their intolerance to cold winter temperatures and susceptibility to various North American fungal diseases to which the redclaw has no immunity.  Also, although they can reach very large sizes, they are generally considered far less aggressive than most native North American species.  Still, there is some concern that their large size may give the redclaw a competitive advantage for food and shelter over the native crayfish.  In southern states, e.g. Florida, it is an accepted, but regulated pond-production species.

There is some thought that crayfish aquaculture, or farming, may help ameliorate the issues associated with overexploitation of wild populations of other high-value fresh-water and marine species.  Although the most cultured and consumed species of North American crayfish are in no way threatened, due to the redclaw’s large size and resemblance to lobsters, aquaculture or aquaponics for redclaw production for high-value culinary markets could help contribute, at least to a small extent, to alleviate pressure on some premium wild finfish (salmon) and marine shellfish (shrimp and lobster) fisheries.

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Crawfish

By C. Greg Lutz, Pramod Sambidi and R. Wes Harrison, Louisiana State University Agricultural Center, glutz@agctr.lsu.edu, psambil@lsu.edu, and rharrison@agctr.lsu.edu.
 
Although both native Americans and Europeans had consumed crawfish for centuries, commercial sale of crawfish (also called crayfish, crawdads or crawdaddys) in Louisiana only began in the late 1800s. At that time, supplies were harvested from natural waters throughout the southern region of the state.

Crawfish aquaculture in Louisiana involves two species: the red swamp crawfish and the white river crawfish. Both species are native to the region and well adapted to coping with the wet-dry cycle found throughout much of the Gulf coastal plains. These species spend most of their life in open water, but they are prone to burrow into the soil when water levels fall and natural backwater and floodplain habitats dry out. Burrowing is particularly important in the life cycle of both species, because the burrow is the preferred environment for females to lay their eggs.
 
The supply chain from crawfish producers to consumers is complex. Crawfish are harvested from production ponds by regular trapping. Traps are typically baited and ‘run’ two to five days per week although some ponds are harvested more or less frequently. Crawfish are packed live into onion sacks (35- to 45-pound capacity) and transported to the first point of sale.
 
Profitability is difficult to define for crawfish production and processing. Prices are variable, generally declining over the course of the season. Yields in production ponds are highly variable and affected by a number of factors, while production costs (primarily harvesting costs) are fairly constant. Estimates of profitability in crawfish farming range as high as $300 to $500 per acre, but $100 to $200 per acre is probably more typical of an average operation. Processors’ profitability levels are difficult to characterize and are influenced by economies of scale, labor availability, types of boiling, cooling and storage systems and market relationships.

Consumption trends for aquacultured crawfish are difficult to evaluate separately from year-to-year variation in availability. Since crawfish are perishable and even frozen tail meat has a limited shelf life, usage generally tracks production. Consumer recognition of crawfish and market acceptance has spread significantly over the past decade, although the volume of Louisiana production consumed in other states is still comparatively insignificant. Consumption of imported tail meat and whole crawfish from China is significant in Louisiana markets and is on the rise in the United States as a whole.
 
Official estimates are not available, but industry observers suggest that Louisiana typically accounts for 90 percent of total U.S. production, depending on the season. Statistics for Louisiana distinguish between farmed and wild crawfish. In 2010 1,202 producers raised crawfish and 1,715 fishermen harvested wild crawfish. The crawfish harvest in Louisiana totaled nearly 110.9 million pounds of pond-raised crawfish, which were sold for more than $168.5 million; the wild crawfish catch totaled 16.6 million pounds and sold for $13.3 million. Limited harvests of farmed crawfish occur in other states, such as Arkansas, South Carolina and Texas. The 2013 (2014) Census of Aquaculture listed 436 farms (mostly in Louisiana) producing $34,637,000 in the 2012-2013 production year.  This is less farms but more or higher-valued product; compared to 648 farms with production valued at $21,148,000 noted for 2005.

Over the years, Louisiana crawfish production has evolved to take advantage of the crawfish's natural adaptations to erratic water levels. As a result, the crawfish production season overlaps portions of two successive calendar years. Ponds are flooded during the autumn, harvest occurs throughout the winter and spring, and draining takes place by early summer to allow for a vegetative crop such as rice to be grown. When the pond is re-flooded the following autumn, the vegetation begins a long, slow breakdown process, providing a debris-based food chain that ultimately results in harvestable crawfish. Under traditional production scenarios, crawfish do not need to be re-stocked.
 
Pond draining in the spring provides a cue for mature crawfish to burrow within the pond levees. Under normal rainfall conditions, sufficient amounts of water infiltrate the soil to maintain a level of saturation within burrowing access for most crawfish, even after ponds are drained. Under conditions of prolonged drought, the saturation horizon can drop to a point where it is no longer accessible. Even under these conditions, however, crawfish can often survive within their burrows as long as humidity levels remain fairly high. Unfortunately, reproduction cannot take place in a dry burrow because some standing water is required to allow for proper fertilization of eggs when they are deposited under the female’s tail.

Females that survive the summer with sufficient water in their burrows typically begin to lay eggs as early as late August. At some point during the fall, a female crawfish will decide to leave her burrow, often with eggs or newly hatched young still attached to her tail. These young crawfish begin growing immediately and can reach marketable size in as little as six to eight weeks. As a result of their reproductive biology, the number and timing of young-of-the-year crawfish entering a pond during any one season are both highly variable. This can lead to size variability, both among ponds and within them. Ponds with relatively low densities tend to produce the largest crawfish, while ponds with excessive reproduction often suffer from stunting, or density-related cessation of growth, prior to the end of the harvest season. With sufficient rainfall or irrigation, red swamp and white river crawfishes are well adapted to live out their life cycles in a typical Louisiana production pond. 
 
A large portion of Louisiana’s crawfish aquaculture, typically in the range of 40 to 70 percent, is practiced in conjunction with rice production. Crawfish can be either be produced in permanent rotation with a rice crop year after year or in a rice-crawfish-fallow rotation, in which re-stocking takes place each cycle. As the economics of rice production in Louisiana deteriorated over the past decade, many rice producers have looked to crawfish as an accessory crop that can be integrated into their existing farming operations.
 
Supplies of crawfish in a typical year depend to a great extent on crawfish life history (growth through the winter and spring months), seasonal demand and a feedback mechanism based on market prices. When prices drop too far, harvesting becomes uneconomical and crawfish are left in the ponds until prices improve or draining must take place. This situation can be further exacerbated when abundant wild-crop crawfish harvests saturate market channels. Many industry observers feel that if crawfish acreage expands significantly over the next several years, an unavoidable consequence will be lower prices for the industry as a whole.

For more information on crawfish production and harvesting, see the Crawfish Production Manual, Louisiana State University. For more information on crawfish production costs, see the Projected Costs and Returns for Crawfish Production in Louisiana - 2010, Louisiana State University.

The two primary sales outlets for pond-raised crawfish are the bait market and the food market. Many fishermen prefer crawfish as a bait because they are readily taken by bass, sunfish and catfish. Small crawfish (less than 1/4 ounce) are the preferred size for sunfish and bass bait while catfish fishermen use crawfish up to 1/2 ounce.

Food crawfish producers have a variety of market options. Most of the crawfish produced in the southern United States is sold to large processors. These processors "peel" the crawfish and extract the tail meat. This meat is then frozen and sold through supermarkets or restaurants in one-pound packages. Tail meat is used in many local food dishes, including gumbo, etouffe and jambalaya. Crawfish is also marketed and sold as live product.

The crawfish industry generates millions of pounds of peeling waste annually along with edible meat. This peeling waste has a low economic value, although it contains highly valuable orange-red pigment and the biopolymer, chitosan. Crawfish shell material is a comparatively inexpensive source of chitosan, which is a potential weight-reduction food supplement with 75 percent fat-binding capacity.
 
Although prices are very uniform among buyers from day to day or week to week during a typical crawfish season, no single buyer or group of buyers can be considered as exerting excessive control over prices. No single buyer or seller of crawfish could be considered to control more than five percent of the market on any given day, but on a local level, brokers and processors can exert concentration advantages. Certain buyers occasionally offer premiums for their larger, more loyal or more consistent suppliers, which in most instances are crawfish growers rather than fishermen. 
 
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Oysters

By C. Greg Lutz, Pramod Sambidi and R. Wes Harrison, Louisiana State University Agricultural Center.

The United States produces two major species of oysters, Crassostrea virginica (the Atlantic oyster or Eastern oyster) and the non-native Crassostrea gigas (Pacific oyster). The Eastern oyster, found primarily in the Gulf of Mexico (Gulf Coast) region and the Chesapeake Bay region, historically accounts for roughly 75 percent of total U.S. harvests. The Gulf Coast region, principally Louisiana, generally leads the nation in oyster production. The Pacific region, principally the state of Washington, follows closely, and the Chesapeake region, principally Maryland, ranks third.

Oysters are typically produced in one of three different ways: natural, managed and cultivated. Natural oysters grow and reproduce without human intervention and are often available for harvest by anyone with the appropriate licenses and permits. In contrast, managed oysters are supervised by harvesters who scrape the oyster beds periodically to reduce clustering. In the case of cultivated oysters, immature oysters are transported to man-made beds where they are allowed to mature. In the Northwest and Northeast, a significant amount of shellstock oysters are produced on cultivated beds, while in Gulf Coast waters, they historically have been largely harvested from wild reefs (Muth et al. 2000).  Following a series of man-made and natural disasters over the past decade, interest in hatchery production and off-bottom oyster culture is increasing in the Gulf region.

Generally, there are four main sectors in the oyster industry: harvesters, wholesalers, processors and retailers. Oyster harvesting includes wild and cultivated harvesting of mature oysters. Harvested oysters are generally delivered to wholesalers and processors; in some cases, they are directly delivered to restaurants or other retail outlets. The wholesalers may repack the shellstock into sacks, boxes or bushels and sell them to other wholesalers or to processors. They may also sell them to restaurants or other retail outlets. They are generally sold in dozens, by the bushel bag or in bushel-fraction boxes.
 
Oysters are harvested in a variety of methods. In areas where oyster reefs are exposed by low tide, they are handpicked. In shallow areas, tongs are used to harvest oysters. Tonging is one of the oldest method of harvesting, where tongs work like a pair of post-hole diggers with handles that are at least 10 feet long. Oysters are also harvested by dredging from oyster boats, using metal baskets with rows of spike-like teeth. Oysters are harvested throughout the year, but the meat yield differs with the season. Oysters harvested in the winter yield roughly eight pounds of oyster meat per sack while oysters harvested in the summer on average yield six pounds per sack.
 
The processing sector buys shellstock oysters from wholesalers and other processors and, in some cases, they directly buy from harvesters. The oyster industry also involves vertical integration, where a fully integrated company may do everything from managing their own seed operation, through growing and harvesting, to shucking-sorting and delivering to wholesalers and retailers. Processing plants manually shuck shellstock oysters and place them in several different sizes and types of containers for sale to restaurants, retailers and other processors. Oysters for the halfshell market are sorted, graded and washed, and later placed in cardboard boxes and burlap sacks.

Processors typically sell oysters as fresh raw shucked, processed halfshell or as other value-added products such as smoked, cooked, canned and breaded oysters. Oysters generally reach consumers live in the shell, as fresh, frozen or canned product, or further processed such as frozen and breaded. Shucked oyster meats are graded and sold according to size in 8-ounce and 12-ounce cups, or in pint, quart or gallon containers.

All oyster dealers in the United States must be certified under the National Shellfish Sanitation Program (NSSP) to market oyster products in interstate commerce. Processing plants that ship oysters are certified as interstate or intrastate shippers. Interstate certified shippers may ship oysters across state lines, while intrastate certified shippers may ship oysters only within their state borders. Interstate shippers are inspected and certified by individual states, which later provide lists to the FDA. The FDA uses this information to publish the Interstate Certified Shellfish Shippers List. Intrastate shippers are also inspected and certified by individual states, but those states maintain their own lists. State agencies involved in certification include departments of health, marine resources, agriculture, natural resources and wildlife and fisheries (Muth et al. 2000).
 
The FDA’s NSSP carefully monitors oysters from their growing waters through processing plants and finally to retail outlets. The NSSP maintains a Manual of Operations, which is routinely revised by the Interstate Shellfish Sanitation Conference, a voluntary group composed of members from FDA, state health regulatory agencies and industry (Perkins 1995).

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Shrimp

By Dan Burden, content specialist, AgMRC, Iowa State University, djburden@iastate.edu.

About 80% of the seafood consumed in the U. S. is imported. Seafood is the second largest U.S. trade-deficit category behind petroleum.  In 2010, the seafood-related deficit was $10.4 billion dollars and increasing.  Shrimp is the most preferred U.S. seafood followed product, consumption is double that of the second-most preferred product, canned tuna (source: fishwatch.gov).  Commercial shrimp species support an industry worth 50 billion dollars a year (Rudloe & Rudloe 2009), and in 2010 the total commercial production of shrimp was nearly 7-million metric tons.

Shrimp are usually marketed according to descriptive product or packaging size wording that is based on “count size.”  This often is confusing to consumers, but is a relatively simple system based on the number of shrimp needed to roughly equal one pound in weight.  For example, count sizes of 10 shrimp or less are “Colossal;” 11 to 15 are “Jumbo;” 16 to 20 are “Extra-Large;” 21 to 30 are “Large;” 31 to 35 are “Medium;” 36 to 45 are “Small;” and 100 or more are called “Miniature.”

World shrimp consumption, fueled by increasing demand from ever-increasing Asian population growth and increasing consumer affluence has led to an increasingly competitive marketplace.  This has impacted both wild-caught and aquaculture-produced shrimp, and has led to large-scale overharvest of ocean stocks, as well as the importation of foreign aquaculture-product that could never meet U.S.-production standards; however, demand is unabated.

In recent years, many consumers have become more aware of both the ecological impact and food-safety issues associated with imported shrimp; consumers also are paying much closer attention to country-of-origin labelling.  The U. S. aquaculture industry for shrimp is in its infancy, but with steadily increasing world demand and increasing consumer awareness, U. S. producers could see strong growth markets.

Additionally, aquaculture shrimp can be an extremely feed-efficient organism to produce.  Since shrimp are low on the food chain, with careful oversight they can be commercially produced under controlled conditions.  Shrimp can be reared on feed pellets in tanks, but research on “counter-current” tank systems has shown that shrimp can be can be fed on highly nutritious “bioflok,” biological flocculent.  This protein-rich food source is a highly oxygenated nutrient and bacterial suspension that can be suspended in the water column and propagated within the shrimp tanks.  The bacteria consume and reproduce from nutrients in the water, then as they propagate, the bacteria clump together into increasingly large particulate masses that eventually reach a particle size preferred by feeding shrimp.  These masses become an almost self-replicating food source and the highly nutritional base for commercial shrimp production.  Depending on species and if given the proper substrate and water chemistry, there is considerable potential to develop highly economical, sustainable and ecologically sound feed systems around “bioflok” or similar production systems.

Systems for producing food in safer ways, including the use of the hazard analysis critical control point (HACCP) system are now being adopted widely throughout the world.  The ever-growing global shrimp and prawn farming and processing industries are now beginning to realize the benefits of using HACCP and other food safety measures.  Commercial producers, large and small, who embrace these systems and communicate their quality control, will find their product increasingly welcome in the marketplace.

Shrimp are highly perishable.  If properly raised, harvested, cleaned, and flash frozen, frozen shrimp can be a fine product.  The informed consumer may want to examine the product label for country-of-origin and similar information before any purchase decisions.  The consumer should select firm product with a mild scent.  There may be hints of ammonia or formaldehyde, or many have spotting on the flesh; signs that the shrimp is past its prime or was improperly handled.  Commercially sold shrimp in most retail settings is defrosted, in which case the flesh will appear opaque.  Truly fresh shrimp like those obtained live from a fisherman or local aquaculture operation, have almost translucent flesh.  In the restaurant and grocery worlds, the term "fresh" should not be interpreted as never-frozen.  It is highly unlikely that the average American consumer will be able to obtain fresh shrimp unless they live in a part of the country near a shrimp-boat fleet or one of the few aquaculture operations that are producing and marketing live shrimp.

Informed consumers may be able to locate some local producers using the MarketMaker and other search engines.  Clearly, with ever-increasing world demand and increasing consumer demand for sustainable and environmentally friendly product, there is great opportunity for local producers of high-quality high-value seafood from aquaculture.

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Turtles

By C. Greg Lutz, Pramod Sambidi and R. Wes Harrison, Louisiana State University Agricultural Center.

The turtle hatchling industry is comprised of individual operators that maintain breeding turtles and collect their eggs during the laying season. Most farmers sanitize and incubate eggs onsite. Marketing channels for red-ear slider (Pseudemys scripta elegans) hatchlings, historically the most common species sold as pets or for grow-out, are limited. Only a handful of major exporters, most of which are also producers, handle the bulk of the industry’s production. In part, this has been a response to the testing protocols required for certification and the investments required to produce salmonella-free hatchlings.

In the past two decades, prices for turtle hatchlings have ranged from $0.21 to over $1.00. While supply and demand forces influence prices from season to season, economic success is generally more influenced within individual operations by capitalization levels, labor requirements and laying, hatching and disinfection rates. Clearly, economies of scale play some role in economic success. In analyses of an industry survey conducted in 1997, Hughes (1999) reported mean and median farm sizes of 6.1 and 2 hectares, respectively, indicating a substantial range in the size of individual operations.

Hughes reported that labor was the single greatest expense incurred by producers, accounting on average for roughly 20 percent of production costs. At approximately 16 percent of operating expenditures, feed was generally the second highest cost category, followed by transportation, at roughly 10 percent. Shipping, fuel, utilities, medications, and repairs and maintenance each accounted for less than 5 percent of operating costs. During the time since Hughes’ study, the proportional costs of feed and fuel have probably increased significantly. Profitability has historically been difficult to gauge, both for producers and brokers. Because demand continues to vary, supplies have been volatile from year to year.

Most of the continued demand for U.S. turtle hatchlings is attributed to buyers in Asian nations, Europe and Latin America where turtles are marketed as pets. China and other Asian countries typically grow hatchlings of various species as livestock for eventual slaughter and human consumption, but as the standard of living increases, there is a renewed demand for novel species and varieties in the Asian pet trade. Although nine other states reported having from two to five turtle farms in the 2005 census of agriculture, few alternative sources for turtle hatchlings exist other than those produced in Louisiana.

Louisiana’s industry is currently responsible for an estimated 60 to 80 percent of the global pet turtle trade. Reported pet turtle hatchling production in Louisiana was virtually unchanged in 2011 from the prior year, with sales of almost 2.7 million hatchlings valued at approximately $1.00 each. As the global economy improves over the coming decade, demand will probably increase in spite of competition from foreign suppliers.

The expansion of turtle hatchling production over the years reflects the relative ease of establishing breeding ponds and sanitizing/incubating facilities. Suitable sites and access to technology are available to anyone wishing to develop a turtle hatchling business. Producers in Louisiana must certify their hatchlings as salmonella-free, which has helped in development of overseas markets for the pet trade. This requiremen