Lumaca romana, (translation: Roman snail), was an ancient method of snail farming or heliciculture in the region about Tarquinia. This snail farming method was described by Fulvius Lippinus (49 BC) and mentioned by Marcus Terentius Varro in De Re rustica III, The snails were fattened for human consumption using spelt and aromatic herbs.
Economic Impact U.S. imports of snails were worth more than $4.5 million in 1995 and came from 24 countries.This includes preserved or prepared snails and snails that are live, fresh, chilled, or frozen. Major exporters to the U.S. are France, Indonesia, Greece and China. The U.S. exported live, fresh, chilled, or frozen snails worth $55,000 to 13 countries; most were shipped to Japan, the Netherlands, and the United Kingdom. Individual statistics are not available for U.S. exports of prepared or processed snails from the U.S. Department of Commerce.
List Of Edible Land Snail Species
Edible land snails range in size from about one millimeter long to the giant African snails, which occasionally grow up to 312 mm (12 1/4 in) in length. "Escargot" most commonly refers to either Helix aspersa or to Helix pomatia, although other varieties of snails are eaten. Achatina fulica, a giant African snail, is sliced and canned and passed off on some consumers as escargot. Terms such as "garden snail" or "common brown garden snail" are rather meaningless since they refer to so many types of snails, but they sometimes mean H. aspersa. Helix aspersa is also known as the French "petit gris," "small grey snail," the "escargot chagrine," or "la zigrinata." The shell of a mature adult has four to five whorls and measures 30 to 45 mm across. It is native to the shores of the Mediterranean and up the coast of Spain and France.
It is found on many British Isles, where the Romans introduced it in the 1st century AD (Some references say it dates to the Early Bronze Age.) In the early 19th century the French brought it into California, where it has become a serious pest. These snails are now common throughout the U.S. It was introduced into several Eastern and Gulf states even before 1850 and, later introduced into other countries such as Australia, South Africa, New Zealand, Mexico, and Argentina. H. aspersa has a life span of 2 to 5 years. This species is more adaptable to different climates and conditions than many snails, and is found in woods, fields, sand dunes, and gardens.
Cepaea Nemoralis Cepaea nemoralis, the "grove snail," or the Spanish "vaqueta", measures about 25 mm across the shell. It inhabits Central Europe and was introduced into, and is now naturalized in many U.S. states, from Massachusetts to California, and from Tennessee to Canada. Its habitat ranges widely from woods to dunes. It mainly eats dead plant material, but it likes nettles and buttercups and will eat dead worms and dead snails. Cepaea hortensis, the "white-lipped snail", measures about 20 mm across the shell which often has distinct dark stripes. It is native to central and northern Europe. This species was introduced into Maine, Massachusetts, and New Hampshire in colonial times, but it never became established in these states.
Its habitat varies but C.hortensis is found in colder and wetter places than C.nemoralis. Their smaller size and some people's opinion that they do not taste as good make C. hortensis and C.nemoralis less popular than the larger European land snails. Helix lucorum, sometimes called "escargo turc," measures about 45 mm across the shell. It is found in central Italy and from Yugoslavia through the Crimea to Turkey and around the Black Sea. Helix adanensis comes from around Turkey. Helix aperta measures about 25 mm. Its meat is highly prized.
It is native to France, Italy, and other Mediterranean countries and has become established in California and Louisiana. Sometimes known as the "burrowing snail," it is found above ground only during rainy weather. In hot, dry weather, it burrows three to six inches into the ground and becomes dormant until rain softens the soil. Theba pisana, also called the "banded snail"or the "cargol avellanenc", measures about 20 mm and lives on dry, exposed sites, usually near the sea. Native to Sicily, it has been spread to several European countries, including England.
This snail is a serious garden pest and is the "white snail" that California once eradicated by using flamethrowers to burn off whole areas. In large numbers, up to 3,000 snails per tree, it can ravage a garden in 24 hours and a citrus or other crop in a couple of nigh
Achatina fulica Achatina fulica and other Achatina species, giant African snails. They can grow up to 326 mm (1 ft ¾ in) in length. Their native range is south of the Sahara in East Africa. This snail was purposely introduced into India in 1847. There was an unsuccessful attempt to establish it in Japan in 1925. It has been purposely and accidentally transported to other Pacific locations and was inadvertently released in California after World War II, in Hawaii, and later in North Miami Florida in the 1970s.
In many places, it is a serious agricultural pest that causes considerable crop damage. Also, due to its large size, its slime and fecal material create a nuisance as does the odor that occurs when something like poison bait causes large numbers to die. The U.S. has made considerable effort to eradicate Achatina. The U.S. Department of Agriculture (USDA) has banned the importation and possession of live Giant African snails. However, they are still sought after as pets due to the vibrant "tiger stripes" on their shells.
Mating and Egg Laying
Snails are hermaphrodites. Although they have both male and female reproductive organs, they must mate with another snail of the same species before they lay eggs. Some snails may act as males one season and as females the next. Other snails play both roles at once and fertilize each other simultaneously. When the snail is large enough and mature enough, which may take several years, mating occurs in the late spring or early summer after several hours of courtship. Sometimes there is a second mating in summer. (In tropical climates, mating may occur several times a year. In some climates, snails mate around October and may mate a second time 2 weeks later.)
After mating, the snail can store sperm received for up to a year, but it usually lays eggs within a few weeks. Snails are sometimes uninterested in mating with another snail of the same species that originated from a considerable distance away. For example, a H. aspersa from southern France may reject a H. aspersa from northern France. Helix Pomatia Snails need soil at least 2 inches deep in which to lay their eggs. For H. pomatia, the soil should be at least 3 inches deep to keep out pests such as ants, earwigs, millipedes, etc.
Dry soil is not suitable for the preparation of a nest, nor is soil that is too heavy. In clay soil that becomes hard, reproduction rates may decrease because the snails are unable to bury their eggs and the hatchlings have difficulty emerging from the nest. Hatchability of eggs depends on soil temperature, soil humidity, soil composition, etc. Soil consisting of 20% to 40% organic material is good. The soil should be kept at 41 to 50 °F (5 to 10 °C), and is best around 70 °F (21 °C). Soil moisture should be maintained at 80%.
One researcher removes eggs immediately after they are deposited, counts them, then keeps them on moist cotton until the eggs hatch and the young start to eat. Snails lose substantial weight by laying eggs. Some do not recover. About one-third of the snails will die after the breeding season. H. pomatia eggs measure about 3 mm in diameter and have a calcareous shell and a high yolk content. H. pomatia lays the eggs in July or August, 2 to 8 weeks after mating, in holes dug out in the ground. (Data varies widely on how long after mating snails lay eggs.) The snail puts its head into the hole or may crawl in until only the top of the shell is visible; then it deposits eggs from the genital opening just behind the head. It takes the snail 1 to 2 days to lay 30 to 50 eggs. Occasionally, the snail will lay about a dozen more a few weeks later.
The snail covers the hole with a mixture of the slime it excretes and dirt. This slime, which the snail excretes to help it crawl and to help preserve the moisture in its soft body, is glycoprotein similar to eggwhite. Fully developed baby H. pomatia snails hatch about 3 to 4 weeks after the eggs are laid, depending on temperature and humidity. Birds, insects, mice, toads and other predators take a heavy toll on the young snails. The snails eat and grow until the weather turns cold. They then dig a deep hole, sometimes as deep as 1-foot (30 cm), and seal themselves inside their shell and hibernate for the winter.
This is a response to both decreasing temperature and shorter hours of daylight. When the ground warms up in spring, the snail emerges and goes on a binge of replacing lost moisture and eating. Helix aspersa H. aspersa eggs are white, spherical, about 3 mm in diameter and are laid 5 days to 3 weeks after mating. (Data varies widely due to differences in climate and regional variations in the snails' habitats.) H. aspersa lays an average of 85 eggs in a nest that is 1 to 1½ inches deep. Data varies from 30 to over 120 eggs, but high figures may be from when more than one snail lays eggs in the same next. Growth Within the same snail population and under the same conditions, some snails will grow faster than others.
Some will take twice as long to mature.However, a snail farmer should obviously select and keep the largest and fastest maturing snails for breeding stock and sell the smaller snails. By selecting only the largest, the average size of the snail may increase significantly in only a couple of generations. Most of the differences in growth are probably due to environmental factors including stocking density. However, to whatever extent these differences are genetic, farmers generally breed large, fast-growing snails instead of small, slower-growing ones. Several factors can greatly influence the growth of snails,these are: population density, stress (snails are sensitive to noise, light, vibration, unsanitary conditions, irregular feedings,touch,etc.), feed, temperature and moisture, and the breeding technology used. H. aspersa requires at least 3% to 4% calcium in the soil (or another source of calcium) for good growth. Most snails need more calcium in the soil than H. aspersa. Low calcium intake will slow the growth rate and cause the shell to be thinner.
Calcium may be set out in a feeding dish or trough so the snails can eat it at will. Food is only one calcium source. Snails may eat paint or attack walls of buildings seeking calcium, and they also will eat dirt. A newborn's shell size depends on the egg size since the shell develops from the egg's surface membrane. As the snail grows, the shell is added onto in increments. Eventually the shell will develop a flare or reinforcing lip at its opening. This shows that the snail is now mature; there will be no further shell growth.
Growth is measured by shell size, since a snail's body weight varies and fluctuates, even in 100% humidity. The growth rate varies considerably between individuals in each population group. Adult size, which is related to the growth rate, also varies, thus the fastest growers are usually the largest snails. Eggs from larger, healthier snails also tend to grow faster and thus larger. Dryness inhibits growth and even stops activity. When it becomes too hot and dry,the snail becomes inactive, seals its shell and estivates (becomes dormant) until cooler, moister weather returns. Some snails estivate in groups on tree trunks, posts, or walls. They seal themselves to the surface, thus sealing up the shell opening. Peak snail activity (including feeding and thus growth) occurs a few hours after sunset, when the temperature is lower and the water content (in the form of dew) is higher.
During daytime snails usually seek shelter. Farming snails Successful snail culture requires the correct equipment and supplies, including: snail pens or enclosures; devices for measuring humidity (hygrometer), temperature (thermometer), soil moisture, and light (in foot candles); a weight scale and an instrument to measure snail size; a kit for testing soil contents; and a magnifying glass to see the eggs. Equipment to control the climate (temperature and humidity), to regulate water (e.g., a sprinkler system to keep the snails moist and a drainage system), to provide light and shade, and to kill or keep out pests and predators may also be needed. Some horticultural systems such as artificial lighting systems and water sprinklers may be adapted for snail culture. Better results are obtained if snails of the same kind and generation are used. Some recommend putting the hatchlings in another pen.
Four Systems Of Snail Farms Can Be Adopted:
Outdoor pens.
In- buildings with a controlled climate.
In- closed systems such as plastic tunnel houses or "greenhouses".
Snails may breed and hatch inside in a controlled environment and then (after 6 to 8 weeks) may be placed in outside pens to mature.
Favorable Conditions
Climate: A mild climate 15–25 °C (59–77 °F) with high humidity (75% to 95%) is best for snail farming, though most varieties can stand a wider range of temperatures. The optimal temperature is 21 °C (70 °F) for many varieties. When the temperature falls below 7 °C (45 °F), snails hibernate. Under 12 °C (54 °F) the snails are inactive, and under 10 °C (50 °F), all growth stops. When the temperature rises much above 27 °C (81 °F) or conditions become too dry, snails estivate. Wind is bad for snails because it speeds up moisture loss, and snails must retain moisture.
Moisture: Snails thrive in damp but not waterlogged environments and thus a well-draining soil is required. Research indicates that water content around 80% of the carrying capacity of the soil and air humidity over 80% (during darkness) are the most favorable conditions. Many farmers use mist-producing devices to maintain proper moisture in the air and/or soil. Also, if the system contains alive vegetation, the leaves are to be periodically wet.
Soil: Snails dig in soil and ingest it. Good soil favors snail growth and provides some of their nutrition. Lack of access to good soil may cause fragile shells even when the snails have well-balanced feed; the snails growth may lag far behind the growth of other snails on good soil. Snails will often eat feed, then go eat dirt. Sometimes, they will eat only one or the other.
A well-functional soil would have the following characteristics:Must contain neither a lot of sand nor too much clay, as snails strive to dig into hard clay and sand dries out easily,20–40% organic matter content. Organic matter enhances cation exchange capacity of calcium and magnesium which in turn stimulates growth.
pH: around 7.
Also,adequate calcium, the primary constituent of shells (up to 98%) is essential. A common way to introduce calcium is to add ground limestone at a suggested concentration of 4.5 kg per 100 square feet (9.3 m2). Calcium may also be set out in a feeding dish or trough so the snails can eat it at will. More advanced techniques involve the addition of polyacrylamide with the following concentration: 12.5 cm³ of a 160 g M.A./one preparation in 250 cc of water per kilogram of dry soil. Such stabilization treatment helps the soil structure resist washing and allows regular cleaning without destroying the crumb structure of the soil that is beneficial for egg laying.
Soil Care: A farmer must find a way to prevent the soil from becoming fouled with mucus and droppings and also tackle undesirable chemical changes that may occur in time.
Soil Mix Suggestions:
Peat, clay, compost and CaCO3 (Calcium trioxo carbonate iv/Limestone)
Leaf mold (at pH 7)
No comments:
Post a Comment