Snails are adept at escaping from enclosures. A priority in setting up a productive snail farming venture, therefore, is to construct escape proof housing. There are several types of snail housing (snaileries) to choose from, depending on the size of the venture. The first step, however, is to select an appropriate site.
The main factors to consider in site selection are the following:
- (Micro) climate
- Wind speed and direction
- Soil characteristics
- Safety, protecting the snails from diseases, predators and poachers
Optimal site selection helps to prevent, or at least reduce, dormancy. Factors such as temperature and humidity and soil characteristics that influence snail survival and growth are discussed below.
Temperature and humidity
Snails are cold-blooded; they thrive best in areas with moderate temperatures and high humidity. In West Africa, temperatures in the areas where most edible species are found do not fluctuate greatly. However, there are significant fluctuations in air humidity, which have a pronounced effect on the GALS species dealt with in this publication. In their natural surroundings, snails go into dormancy during the dry season.
Relative air humidity should not be near saturation, because it would encourage the development of harmful bacteria and fungi. In outdoor situations, it is clearly impossible to control climatic factors. However, the magnitude of temperature and humidity fluctuations is reduced in areas of relatively undisturbed forest or fairly dense vegetation cover. Such sites should be preferred to open grassland or farmland areas.
Obviously, snails can be reared in a completely controlled, indoor environment, but at a price. Whether the investment will be profitable depends on one's financial resources, local production costs per kg snail meat, and marketing options.
Wind speed and direction
Wind accelerates moisture loss in snails. To prevent snails from drying out, snaileries should be situated in sites that are protected from the wind. Downhill sites are usually the most suitable, preferably those with good tree cover to reduce wind impact. Planting (fruit) trees around snail pens will help to reduce wind speed and improve the micro-climate. It will also protect the snails from scorching sun or torrential rain.
Soil is a major part of a snail's habitat. Soil composition, water content and texture are important factors to consider in site selection.
- The snail's shell is made up mainly of calcium derived from the soil and from feed.
- Snails derive most of their water requirements from the soil.
- Snails dig in the soil to lay their eggs and to rest during the dry season.
For all these reasons it is essential that the soil is loose and that its calcium and water content is high.
- Heavy, clayey soil that becomes waterlogged in the rainy season and compacts during the dry season is undesirable.
- Very sandy soil is undesirable as well because of its low water holding capacity.
- Acidic soils should be avoided because acidity would interfere with the development of the snail’s shell. Soils that are too acidic might be neutralised with lime to about pH 7.
- Soils with high organic matter support the growth and development of snails. In general, if a soil supports good growth of cocoyam, tomatoes and leafy vegetables, it is suitable for snail farming.
- Before introducing snails to the site, the soil should be loosened by tilling.
- Snails need damp, not wet, environments. Although snails need moisture, you must drain wet or waterlogged soil. Similarly, rainwater must run off promptly. Snails breathe air and may drown in overly wet surroundings. A soil moisture content of 80% of field capacity is favourable. In the hours of darkness, air humidity over 80% will promote good snail activity and growth.
Most snail activity, including feeding, occurs at night, with peak activity taking place 2 to 3 hours after the onset of darkness. The cooler temperature stimulates activity, and the night-time dew helps the snail move easily. Snails like to hide in sheltered places during most of the day. In Nigeria, shredded semi-dry banana leaves are put in the snail pens for the snails to hide under during daytime.
To maintain adequate humidity and moisture levels in drier locations, misting sprayers can be used (like those used for plant propagation) -if technically and economically feasible.
Snail shells are 97-98% calcium carbonate, therefore calcium must be available to them, either from the soil or from an external source(ground limestone, egg shells and so on, see Chapter 5). Organic matter in the soil is as important as carbonates. Soils that are rich in exchangeable calcium and magnesium stimulate growth best. Calcium may also be set out in a feeding dish or trough so the snails can eat it at will.
Snails dig in soil and ingest it. Good soil favours snail growth and provides some of their nutrition. Lack of access to good soil may result in fragile shells even if the snails have well-balanced feed; the snails’ growth may lag far behind the growth of other snails on good soil. Snails often eat feed, then eat dirt. Sometimes, they eat only one or the other.
Eventually the soil in the snail pens will become fouled with mucus and droppings. Chemical changes may also occur. The soil must, therefore, be changed once every three months.