The purple snail Is an importanl cconomlc ipeciet bccuusc of ihe ilyc obtaincd Ttom It in wcstern ... TyrÃan purple dye, after a complicated extractlon proeess. This.
Journal qfShtUfith
Rtitorch,
V o l . 19, No. 2, 9 1 3 - Í I 7 . 2000.
E F F E C T O F R E P E T I T I V E D Y E E X T R A C T I O N O V E R Y I E L D AND S U R V I V A L R A T E O F T H E P U R P L E SNAIL PUCOPUnfURÁ PANSAiGOVLD,
1853)
JESÚS E M I L I O MICHEL-MORFÍN*'* AND E R N E S T O A. CHA V E Z O' ^Centro de Ecología Costera Universidad de Quadahjara Cómei Parias S2, San Patricio-Metaque Jalisco 48980 México. "^Centro ¡mtrdisciplinario de Ciencias Marinas- !PN Playa El Conchólilo s/n Apdn Poaial 592, La Paz BCS, 23000. México ÁBSTRÁCT
The purple snail Is an importanl cconomlc ipeciet bccuusc of ihe ilyc obtaincd Ttom It in wcstern McxicO. This dyc híis
been uscd jlnce »ricient times to eolor ceremonial dressej purple. Otí^er snalI» produce dyc, but PUeopurpura pansa dye emracilon was done wilhout klllinfi the snail, Repelilive dyc exlrsction \f, possible. The bcsi time beiween each milking. dye yield vcrsus milking frequency, and elTecl on lurvival WB.f delermined by repelilive milking inaíl groups severíil iim«S (7. 14, 31, Hnd 28 days). Morulity in thí mosi frequenlly milked groups and dye yield reduciion oceurred (every 7 and I4 dayj), Wher milking frequency occurred every 21 days, the bcst dye yield and 100% turvival r,ito wat obscrvcd, Th
WORDS:
mollusfci, purple tnail, cxploltaiion, natural dyc«, PUeopurpura pansa
«cu'víiy has e."iisled from before the lime of Columbus (Turok
INTRODUCTION
Severa! animal nnd vegetable producís have been uscd for mitennia by díffcrent cultures to iupply dye,'; (Baranyovits 1978). Among all anclent natural dyes, ihosc using marine gasiropods were the mo.st prestlgious, and the textilc industry citablishcd was One of ihe most impottani and complex i n Europe and Mideast (Korcn 1995), Several .species from genera Purpura. PUeopurpura, Murex, and 77i«(f were uscd lo obtaín puqjlo and bluc dycs (Baker 1974. Fox 1966, Ghiretti, 1996), Tltese colors have been symbollcally reliied wjih importanl and powerful people. . A l ihc inicrtidal zone of the easiem iropical Pacine, purple sniiil or dye snail PUeopurpura pansa (Gould, 1853; Synonymous: Purpura pansa), is a valuable species because of the Huid produced in the hypobranchial gland, Aftcr secretion. this dye changes from ¡(s initial white color to purple by a chcm'ical reduciion. Unlikc oihcr snail dye producers in which it Is neccssary to brcak the shcll and to kill the animal to obiain the dye gland, dye extraclion from P. pansa it made by mechanically exciting the snail foot and operculum, i o múltiple milkings can b* made, Friedlander determlned that 12,000 Murex snails were ncccssaiy to obtain only 1,4 g of Tyrían purple dye, after a complicated extractlon proeess. This explained the rarity and high cost of such dyes in the past (Friedlander 1908 in Baranyovits 1978). Natural colors are again becomirtí desirable, and their use for dylng fabrle is Increasing. In the late 1980s on the rocky shorcs of the Mexican Pacific coast, a smalUscale Ilsbery ofpurple shell was dcvclopcd to suppoft a Japanese markct for dyc of cxpcnsivc k i monos, Howevcr, this fishcry was looJdng for Ihe hlghest dye yield, and the time between milkings was not considcrcd; therefora, tho local purplo oholl otock was depleled in a aksrt lime (Turok et al. 1988), Sincc 1988, the Mexican Oovemment has had P, pansa under special protecllon (Anonymous 1988, Anonymous 1994). Currcntly. the purple snail is used only by the Mlxtcco people on the coast of Oaxaca to make ceremonial dresses. This
1996). To siudy reproduction (Accvcdo 199') and feeding a. 0.05), i n length or i n weight. Tlte se-iual
obs ¡rved i n thc diffcrcnt groups approached a 1:1 male—fe nule laiio. Figure 2 shc ws thc rcsults of thc survival rate obscrvcd in each One of tht grou is .subjccted to different milking regimes during the study. Grjups vith dye extraclion at 2 i and 28 days showcd no mortality In co urast, groups wiih a milking frequency of every 14 days ( ü l i), hal a 95% survival ratc, and the beginning of morproportio
T A B L E 1.
Size, weight, ai^d sexual propnrtlon of snatl groups under dirTerent milking regimt. Groupi Param itert Average s{ze' Minímuni í w e "
Máximum íize' S D i n tizc' Avtirafie Vieilighl" Mínimum jweligh Máximum WClIgh* SD wcighi[' n fcniBlcí fl males ' Length si ze, m I» "Wcighi,
07
CU
G21
G28
Gw
Total
35.3 25,3 513 8,5 7.8 2.J 21,1 S.t 11 9
36.0 25.0 51,8 7.S 8.3 2.6 22,3 6.3 10 10
36.3 24,5 61,1 11.2 9.0 2.8 30,6 8.9 9 11
34.7 27,3 51,3 7.4
32,4 19,8 52,5 10.1 8,1 1.4 24.2 7.8 6 6
35.1 19.S 61.1 8.9 8,1 1.4 30.6 6.1 47 47
6,9 2,9 16.0 4.6 II 9
EFFECT OF DYE EXTRACTION O N T H E SNAIL
915
Figure. 2, Pcrccntísc of survival for each purple snail group dtiríne mllkinc period, CA tallíy was shüwn in ihc ninih week (al the Tourlh milking). In the group (C37) with weckly dye extraclion, the lowest valúes of survival rate (85%) were observed, and snail nnortalily began at the iixth week (at the flfth milking), An accidental death of a snail in the control group was reeorded at ihe second week of th» experiment, Evidence shows the possible existence of a modérate effect of milking frequency on survival; howevcr, thc valúes of dye prodüction analyzed for each group indícate that repeiitlve dyc extraction is importanl. The mean volume of dye produced in rolatlon to shoU longth is shown in Figure 3, The volume ofdyc/snail using thc dala of thc ílrst milking was determined. and an avcragc valúe of 0,47 m U snail was obiained (SE m 0.03). It was not possible lo obtain dyc in 12 out of 94 snails (12,7 % ) . A powcr rcgrcssion cstablishing tho relationship botwccn the length (L) and the votume of dye (D) of the snails was estabti.6, Prueba de seli diferentes d¡eu« «n «l caracol morado (Oouid. ]tii) en cautiverio. TCSÍ.Í Profesional. Lic. en Purpur i pai Ecolog á Mar na. Universidad Autónoma de Guerrero. México. Rfos-Jani, :.. H. León. L. Lizírroga-Chívez & E. Michct-Morffn. 1994. fxiiulo Produc ;lón y|ticmpodc recuperación del tinte de Plkvpurpura pansa (^Jcoji itropoda: Muricidac)cn Jalisco. Míxico. Rav. Btní. Trnp, 42(3):5]J7-S41 Turok, M . 1996. Kiuhqullltl, noehezlli, y Tixinda, Tinle.i del .Mdxico an^2•.26-3i. liguo. - rquectojffa Mtxlcana Sigler. E. Hernindeí, J. Acevedo. R. Lara & V. Turco», Turok. M . 1988. I i l caraiiel Purpura una tnndielón milenaria en Oaxaca. I3ireccíón Genera d c C ilturas Populares, SEP. M í x i c o . 166 pp. Zar, J. H . 1996, B iostiilislical analysis. 3rd «d. Prenllcc Hall, Uppcr .Saddic Rlver, f i e * J irsey. 662 pp.
