El loco Concholepas concholepas (Bruguière, 1789) (Mollusca: Gastropoda: Muricidae) como recurso durante el Holoceno Temprano-Medio en Los Vilos, Chile central

Abstract

RESUMEN.Se estudió la abundancia relativa del loco, Concholepas concholepas, y las causas posibles de su variabilidad en los conchales culturales más antiguos del Holoceno Temprano-Medio del litoral de Los Vilos (31º55'S, 71º32'W). Las muestras se obtuvieron en excavaciones arqueológicas de cinco sitios y se dataron con C 14 : Punta Purgatorio (LV079: 10.040 ± 70 años antes del presente, a.a.p.), Caleta Ñagué (LV098: 10.120 ± 80 a.a.p.), Dunas de Agua Amarilla (LV166: 6.700 ± 60 a.a.p.), Borde Norte de Quebrada de Quereo (LV036, 6.030 ± 80 a.a.p.) y Fundo Agua Amarilla (LV099: 5.480 ± 70 a.a.p.). Las conchas corresponden a ejemplares juveniles y adultos jóvenes, cuyas tallas varían entre 20 y 145 mm. Este amplio rango de tamaño refleja que los recolectores que formaron los conchales extrajeron los moluscos sin selección de tallas. La mayoría de los especímenes son de talla superior a 50 mm, longitud que corresponde a la talla de primera madurez en las poblaciones de locos actuales. La abundancia de esta especie en los conchales es mayor en los sitios más recientes: 46.200 ejemplares en LV166 y 4.185.000 en LV036. La variabilidad observada en los registros sustenta la hipótesis que éstos fueron motivados por cambios paleoclimáticos que afectaron directamente las características ecológicas de la región, las que influyeron, indirectamente, en la extracción de las especies.Palabras claves: Concholepas concholepas, gastrópodos, Holoceno, recursos costeros, Los Vilos, Chile. ). These gastropod shells correspond to juvenile and young adult specimens, whose lengths oscillate between 20 and 145 mm. The wide range of sizes found indicates that collectors did not make mollusk selection by sizes during the captures. The majority of these specimens are of a size longer than 50 mm. This latter length corresponds to first maturity size found in current Concholepas concholepas populations. The abundance of this species in the shellmidden is greater in the most recent sites: 46,200 specimens in LV166 and 4,185,000 in LV036. The variability in the records substantiates the hypothesis that the principal cause in the observed changes was originated in palaeoclimatic changes that affected directly the ecologic characteristics of the region, and influenced, indirectly, the species extraction. El loco

Reconstructing the history of human impacts on coastal biodiversity in Chile: constraints and opportunities

“…30-331S) have yielded mixed results (Jerardino et al, 1992;Baez et al, 2004). On the one hand, Jerardino et al (1992) reported a marked decline in the shell size of C. concholepas observed during an $8000 years period of occupation, from 9000 to 1300 years BP at the Curaumilla site (331S).…”

“…On the one hand, Jerardino et al (1992) reported a marked decline in the shell size of C. concholepas observed during an $8000 years period of occupation, from 9000 to 1300 years BP at the Curaumilla site (331S). However, Baez et al (2004) presented data showing no decline in the shell size of C. concholepas at Los Vilos site (ca 321S) during a ca 4500 years occupation period (9200-3900 years BP), during the mid-Holocene. These results suggest that human impacts were spatially variable and/or the resilience of rocky intertidal communities to human impacts was variable along the coast.…”

“…However, the analyses of body size of harvested molluscs in shell middens may be used as an indicator of human impact (Jerardino, 1997;Milner et al, 2007). For example, it is well known that prehistoric gatherers exploited intertidal populations of the muricid snail C. concholepas ('loco') more than 9000 years BP (Llagostera, 1979;Jerardino et al, 1992;Baez et al, 2004). The 'loco' fishery is currently overexploited (Buschmann and Pe´rez Matus, 2003), and studies conducted at marine reserves have shown the mean shell length of nonharvested populations of 'locos' is typically 2-3 cm larger than in open areas of the coast (Castilla, 1999;Moreno, 2001).…”

“…Analysis of shell middens along the temperate south-eastern Pacific coast reveals that indigenous populations extracted large amounts of molluscs including a high diversity of intertidal and shallow subtidal species (Llagostera, 1979;Reitz, 1988Reitz, , 2001Aldenderfer, 1989;Jerardino et al, 1992;Siegfried et al, 1994;Sandweiss et al, 1996;Sandweiss, 2003;Baez et al, 2004). The pervasiveness of human harvesting activities is revealed by a preliminary analysis, based on a literature review: 76% of rocky intertidal gastropods (42 out of 55 species) currently found along the coast of Chile (between 181 and 421S) are recorded in shell middens of the region (Llagostera, 1979;Jerardino et al, 1992;Vasquez et al, 1996;Gaete et al, 2004;Mendez and Jackson, 2004;Torres et al, 2007).…”

Variabilidad ambiental y recursos pesqueros en el Pacifico suroriental: estado de la investigacion y desafios para el manejo pesquero

“…El loco (Concholepas concholepas) se distribuye desde la costa central de Perú a Magallanes (Moreno et al, 1998) siendo extraído por las comunidades litorales desde el Holoceno temprano (Báez et al, 2004;Rivadeneira et al, 2010). A fines de la década del 70's y comienzos de los 80's, los desembarques aumentaron (incentivos por demanda y precio) disminuyendo drásticamente poco después de El Niño 82-83 en la zona norte (Regiones I-III), segunda mitad de la década (Regiones la IV y X), y a mediados de los 90's al sur (B. Yannicelli, com.…”