Millenary cultures have used the dye of certain gastropod mollusks to dye their clothing. In this history of colors and dyes, purple has always been a symbol of greatness and power. Already in ancient Japan, the dye of a species of snail called imperial purple was used to dye the garments of emperors and noble marriages. In pre-Hispanic America, purple blankets were also a very important attribute. In Mexico, for example, this color was obtained from the Purpura pansa snail, whose dye is indelibly fixed by the combined action of oxygen and light. The snail was also appreciated for its shell, which was attributed with meanings about birth and fertility.

During the colonial period, the Mexican tradition of dyeing with the purple snail was maintained. In the coasts of Oaxaca, Michoacán, Colima, and Jalisco the Mixtec, Nahua, Chontal, and Huave groups continued traveling to the coasts during a certain time of the year to take the snails out of the sea, dye them and return them to their environment. But with time it was the Mixtecs and Nahuas who preserved this tradition with more perseverance, which is currently maintained only by the Mixtecs of the town of Pinotepa de Don Luis on the coast of Oaxaca with an important significance for their culture and economy. However, the conditions of exploitation of the Purpura pansa snail have changed. In what state is this resource now?

Until the early eighties, during the months of October to March, the Mixtec tefiidores ("dyers"), in groups of 4 or 5, traveled 200 kilometers to reach the twenty bays of Huatulco, where the Purpura pansa snail was abundant. In the bays themselves, they dyed their cotton skeins with the snail dye. Then they would return and sell the purple skeins to the weavers of the town. This is how the making of posahuancos, those skirts with religious and magical meaning, associated with fertility and death, was maintained for years.

The situation of the snail until then maintained population stability, given that the Mixtecs used them at appropriate times, when their reproduction was not affected, in addition to the fact that they managed the resource rationally. Their way of extracting the dye consists of detaching the live snail from the rocks with great care and placing it on the skeins of thread so that these are dyed (this is called ordefio); then they return the mollusk to a shaded part of the stone and pour seawater on it. However, from 1981 to 1985 the situation of the snail changed drastically due to the exploitation carried out by a foreign company that extracted the dye with inadequate methods. This led to a decrease in the population of snails on the beaches where the Mixtecs traditionally dwell.

After these facts were denounced by the Mixtecs and after biological, ethnobiological, socio-economic, and cultural studies, an Intersecretarial Agreement was reached to take advantage of and conserve the Purpura pansa. The Agreement, which was published in the Official Gazette on Wednesday, March 30, 1988, states that it is forbidden to kill this mollusk to extract its dye, to move it out of the area where it lives, or to commercialize any part of the snail other than its own dye. Something very important about this Agreement is that it states that the dye can only be used by members of the indigenous communities that have traditionally exploited it. Although the credentials-permits granted by the Ministry of Fisheries for the exploitation of Purpura pansa must be renewed every two years, the Mixtecs have requested that these credentials be converted into a twenty-year concession, based precisely on their long tradition that had not affected the resource.

There are some unsolved difficulties in the conservation of Purpura pansa. One of the most serious is that this species inhabits attractive places for tourism and hotel constructions along the Pacific coast and especially the development of Huatulco causes a lot of terrigenous material to escape into the sea, which affects the snail and its marine environment. For the areas already affected by these and other reasons, repopulation with captive-born individuals was considered.

In pre-Hispanic America, purple blankets were a very important attribute.

The traditional area of exploitation of Purpura pansa by the Mixtecs in Oaxaca was from Barra de Copalita to Puerto Angel. Due to tourism development, this zone has been limited, and they can only exploit ten of the twenty bays that were traditionally exploited in the Huatulco area. There are, however, other areas that could be exploited, such as those between San Agustín Bay and Cacaluta Bay. Although this area is currently visited by the boats of the Bahía de Santa Cruz tourist cooperative, it could also be used by the dyers and even reach an agreement with the cooperative members to demonstrate dyeing and obtain their traditional income.

According to the research that has been carried out, approximately 120 liters of dye could be extracted in the coastal zone of Oaxaca in a period of six months. This calculation is based on the following rules: there must be a rotation in the dyeing areas, the minimum size of the milking snail must be 3 cm, it is necessary to keep them in the shade and with sufficient humidity during the time they are out of the sea so that when they are returned to their substrate they have a quick recovery, and the established closed period must be respected.

One issue that should be analyzed is that buyers are paying too cheaply for dye. Perhaps a market study should be done so that the dye acquires an adequate value. In order to carry out a good use and production of the Purpura pansa snail, a process must be integrated with the participation of the people who live in the area, in order to achieve an integral use of the region's resources. Perhaps dye could be extracted in other states where the species is found in abundance, such as Jalisco. But in this case, it would be necessary to a good training of the people of the zone so that it is carried out in a rational way.

The situation of the purple snail continues to be serious due to the activity of other human groups that act in the area during the whole year and collect the snail with other means than dyeing. Among the causes that are already recognized is the affectation caused by iguana hunters, who collect chitons (dog's tongue) for food during their expeditions. These chitons are an essential food source for the Purpura pansa snail. Other impacts are due to the construction of tourist structures, which have caused landslides and modified the topography of the rocky intertidal zones, as well as the action of tourists and other aquatic activities; recently there have been rumors that the snail is being collected to make cocktails.

It must be recognized that tourism needs to be nourished by the environment. In the case of the purple snail, it is possible to take advantage of the very fact that the dyeing process itself is interesting. This can become one of the tourist attractions, and at the time of the dyeing, these ethnic groups can demonstrate the process that they handle so well. The sale of the dyed textiles could remain in the hands of the mestizo groups of the zone so that the whole population benefits and an economic benefit is achieved.

This history of colors and snails that already adds hundreds of years in Mexico must conserve its harmonic conception. The natural dye of the purple snail and its ecological, social, and economic values has its place, as important in the future as the one it has managed to maintain up to the present.

By Emma Romeu, Source: Biodiversitas (6) Mexico: CONABIO