1. Introduction

In a continental climate, characterized by higher rainfall levels than on countries with tradition in snailfarming (France, Italy, Spain, Greece), in Romania this activity registered a booming development during the 2003–2007 time period [1]. Thus, in 2006, according to the International Institute of Snail Farming from Cherasco (Italy), Romania ranked second in the world concerning the number of outdoor snailfarms (>1000) and their sown area. The "French" snailfarming technology implies that the snails are bred in captivity, and juveniles are introduced early in the spring in outside fattening pens, wherein they are fed primarily a combination of concentrated fodders [2]. As a result, most snails reach adulthood from 6 to 8 months, and in autumn they are sold as final product. Only a small proportion of adult gastropods is kept as reproductive herd for the next year productive cycle and hibernate in strictly controlled indoor environment [3]. The immature juveniles are not gathered; therefore, they are let to survive outside during wintertime, without any additional protection [4]. In contrast, the "Italian" snailfarming technology snails employs the biological cycle of raising and growing snails in open pastures of fresh vegetables [5]. A typical farm is organized in pens with precise destinations: 60% for breeding and 40% for fattening [6]. The fattening pens are used starting from the second year of activity onward, when after hibernation, snails are transferred from the breeding pens into the fattening pens [7]. When winter arrives, snail of many sizes, starting from hatchlings to adult ones, are found inside the pens [1]. The solution used for snail hibernation relies on trimming the vegetation inside the pens to 20 cm in height, whereas the pens are covered with unweaved coverlet (weight = 18–25 grams per square meters, i.e., g/m<sup>2</sup> )—material also known as agryl sheet [8, 9].

microclimate parameters on the snails' intermediate survival rate (Sli) and final

The experiments of this pilot exploratory study were conducted in three snailfarms chosen based on their location, technological flow, and microenvironment parameters: Floreşti (Mehedinţi county; latitude, 44°75'; longitude, 22°92'), Sântuhalm (Hunedoara county; latitude, 45°85'; longitude, 22°96'), and Muntenii de Sus (Vaslui county; latitude, 46°70'; longitude, 27°76'). The farms were carefully monitored since their implementation: 2005 (Muntenii de Sus) and 2006 (Floreşti, Sântuhalm). The reproductive herd was imported from Italy. The data were carefully monitored and recorded into technological evidence files. Next, they were used for five case studies (Table 1) depending on location and snail size: Cs1 (Floreşti, juvenile H. aspersa juveniles); Cs2 (Floreşti, mature H. aspersa snails); Cs3 (Sântuhalm, juvenile H. aspersa snails); Cs4 (Sântuhalm, mature H. aspersa snails); and Cs5 (Muntenii de Sus, juvenile H. aspersa snails). Field observations performed in 40 outdoor snailfarms from 2004 to 2007 indicated that, under Romanian pedoclimatic conditions, the mating season began in June, with most juveniles hatching in September. This does not allow the juveniles to exceed 1.0 cm in shell diameter till hibernation, and therefore, we considered that the snail size was homogeneous enough to provide accurate data. Moreover, before being hibernated, they were carefully selected by using a fine strainer (φ mesh = 1.15 cm). Thus, the term "juveniles" defines in this study young snails with shell diameter up to 1 cm. The indoor hibernation experiments monitored the survival levels of juvenile and mature specimens of H. aspersa in relation to three primary parameters: tempera-

First, two distinct locations were selected for these studies: Floreşti and Sântuhalm. Two lots were sampled from each location, one containing only juvenile H. aspersa snails and another only mature H. aspersa snails: Floreşti (Cs1, Cs2) and Sântuhalm (Cs3, Cs4). About 5 kg of juvenile H. aspersa snails were collected for each location. Five lots, about 100 g each (S1–S5), were aleatory collected for each location. Next, the number of juveniles was counted for each lot. Then, we estimated the individual average weight before hibernation (Wb) for each sample as the ratio between the total weight and the number of juveniles. After that, we estimated the number of hibernating juveniles (Nb) as the ratio between the total sample weight and Wb. During indoor hibernation, high death rates were recorded for juveniles, with each sample taken into account weighing after hibernation about 50 g. The individual average weight (Wa) and the number of juveniles for each sample (Na) after hibernation were assessed in the same manner as for before hibernation. Then, the survival level was calculated as the ratio (%) between Nb and Na. We also determined the weight loss during hibernation (Wl) for each sample as the difference between Wb and Wa. Then, the percentage weight loss (Wl%) was calculated as the ratio between Wl and Wa. For their mature

juveniles recorded during the first stage of our pilot exploratory study.

Then, we analyzed weight variation of H. aspersa juveniles during indoor hibernation (Wl, Wl%). The second stage assessed the viability of this novel approach before its extensive application, in relation to Slo and death levels of H. aspersa

survival rate (Slf).

2. Materials and methods

Indoor Hibernation of Helix aspersa Juveniles DOI: http://dx.doi.org/10.5772/intechopen.88732

ture, humidity, and ventilation (Table 1).

2.1 Hypothesis testing

5

High death rates have occurred in snailfarms all around Romania during the winter of the year 2006, proving that the standard outdoor hibernation technology is not well suited for colder climates (temperate continental climate). As a result, our research focused on finding some alternative paths for a proper hibernation of H. aspersa in colder climates. One solution was the development of "sandwich" system—a protective structure based on the nonconducting properties of the straw, on soil thermic inertia, and the insulator properties of nylon sheet. This system was tested at micropilot level in 2006 [9] and was extensively used in outdoor snailfarms [1]. However, two additional possibilities were also tested: indoor hibernation of H. aspersa juveniles and indoor rearing of H. aspersa juveniles during wintertime. It is known that during hibernation, the gastropods' vital functions decrease to subsistence level [10, 11] and the shell aperture is sealed with one or several epiphragms [12], allowing these terrestrial mollusks to survive in a stage of dormancy up to 4–6 months [13]. Indoor hibernation of mature snails, H. aspersa, in a controlled environment, temperature 2–6°C and humidity 70–80% [14], allows at least 80% of them successfully to pass overwinter [4]. We considered that indoor hibernation could represent a possible solution for H. aspersa juveniles, if this approach can be adapted for their physiological needs. The optimal survival level (Slo) of mature snails during hibernation (80%) was considered as a benchmark to assess the viability of this technology for H. aspersa juveniles. The experiments of this pilot exploratory study lasted 2 years and were performed in two distinct stages, in three snailfarms, and on 34,000 juvenile specimens of H. aspersa and 15,000 mature specimens of H. aspersa, using different technological flows and microenvironment parameters (temperature, humidity, and ventilation). Within the first stage, we conducted mixed experiments, using both mature snails and juvenile snails to evaluate the influence of technological flow and variable

#### Indoor Hibernation of Helix aspersa Juveniles DOI: http://dx.doi.org/10.5772/intechopen.88732

microclimate parameters on the snails' intermediate survival rate (Sli) and final survival rate (Slf).

Then, we analyzed weight variation of H. aspersa juveniles during indoor hibernation (Wl, Wl%). The second stage assessed the viability of this novel approach before its extensive application, in relation to Slo and death levels of H. aspersa juveniles recorded during the first stage of our pilot exploratory study.
