Reestablecimiento de Choromytilus chorus (Molina, 1782) (Bivalvia: Mytilidae) en el norte de Chile

Abstract

RESUMEN.Hasta fines del siglo pasado no existían registros de la presencia de Choromytilus chorus al norte de los 23°S, pese a antecedentes que señalaban su existencia en épocas pasadas. Ciertos cambios relacionados con las masas de agua costeras de esta zona, habrían generado la ausencia o escasez que presentaba el entorno costero actual. Sin embargo, hace una década atrás, su presencia en el norte de Chile, comienza a tener connotación pesquera. En el presente trabajo se confirma su reestablecimiento en las regiones de Antofagasta y Tarapacá, mediante prospecciones realizadas en seis lugares donde se registró su presencia, así como mediante la captación de semilla en colectores suspendidos. Se indica interacción con Aulacomya ater, a la cual ha desplazado a estratos más profundos, mientras que su reestablecimiento, iniciado en las regiones de Atacama y Antofagasta, y que se amplió posteriormente a la región de Tarapacá; permite postular la hipótesis que la dinámica de estos bancos, respondería a una estructura de metapoblación, dado el sistema de corrientes y vientos que predominan en la zona norte, permitiendo la advección larval de poblaciones existentes en la región de Coquimbo. Palabras clave: recolonización, Choromytilus chorus, norte de Chile, Pacífico suroriental. Reestablishment of Choromytilus chorus (Molina, 1782) (Bivalvia: Mytilidae) in northern ChileABSTRACT. Despite indications of its presence in past ages, until the end of the last century, no records showed Choromytilus chorus north of 23°S. Certain changes related to coastal water masses in the zone could be responsible for the present lack or scarcity of this species in the coastal area. However, a decade ago, this species appeared in northern Chile in the context of fisheries. This study confirms the re-establishment of C. chorus in the Antofagasta and Tarapaca regions through surveys at six sites where the species had been registered and spat collection using suspended collectors. This species has interacted with Aulacomya ater, displacing it towards deeper habitats. The re-establishment of C. chorus began in the Atacama and Antofagasta regions and later extended to the Tarapaca region. Thus, we hypothesize that the dynamics of these shoals correspond to a metapopulation structure that has allowed larval advection, given the current system and predominant winds in the northern zone, from populations existing in the Coquimbo region.

Evaluation of culture of the mussels Choromytilus chorus and Aulacomya ater (Molina) in northern coasts of Chile

“…The efficiency of the competition observed for Ch. chorus in this study was also detected in the re‐established natural beds in northern Chile, where A. ater was displaced to depths beyond 15 m when occupying the shallow (4–13 m) strata (Avendaño & Cantillánez ).…”

“…). Punta Arenas Cove (21°38′S; 70°09′W) has a natural bed of A. ater distributed from 15 m down to depths beyond 30 m. Choromytilus chorus inhabits sectors in the shallower areas that range from 4 m to 13 m in depth (Avendaño & Cantillánez ). The presence of both species permits the spat to anchor onto the collectors in this area (Avendaño & Cantillánez ), which is why this area was selected for collection.…”

“…Until the end of the last century, there were no records of this species from the northern area of the country (ca 23°S) to Peru. However, Avendaño and Cantillánez () confirmed its recovery in the shallow area of the Big North of Chile at the beginning of 2000, which provoked the displacement of A. ater to the deeper areas and banks.…”

Loco or no Loco? Holocene Climatic Fluctuations, Human Demography, and Community Based Management of Coastal Resources in Northern Chile

“…Indeed, P. purpuratus is the most dominant (28%) mussel species in the Early Archaic (Figure 3) which implies a certain cultural preference community base management decision (Tompkins and Adger, 2004) for specific food items by these coastal peoples at this time. In this regard, ENSO-induced changes in coastal SST could be responsible for such patterns, as C. chorus and P. purpuratus prefer cool and warmer waters, respectively (Diaz and Ortlieb, 1993;Avendaño and Cantillánez, 2011). Because increased upwelling implies decreased SSTs along the Pacific coast of South America, we would expect an increase in C. chorus blue, Concholepas concholepas proportion: red, Choromytilus chorus proportion: light green, Aulacomya ater proportion: dark, Perumytilus purpuratus proportion: cyan, Acanthopleura echinata proportion: magenta, Loxechinus albus proportion: yellow, Mussels proportion: olive.…”

Reproductive cycle, collection and early growth ofAulacomya ater, Molina 1782 (Bivalvia: Mytilidae) in northern Chile

“…In the Pacific, this resource has been the target of an important fishery, both in Chile and Peru: in 1999, extractions of A. ater reached nearly 20 000 tonne in these two countries (FAO ). Nevertheless, in recent years, A. ater extractions have been heavily reduced, mainly in northern Chile, where rates fell up to 57.7% in the Tarapacá Region and up to 6.4% in the Antofagasta Region between 1999 and 2008 (Avendaño & Cantillánez ). This fishery had already been reported to be in decline in southern Chile, where natural beds of mytilids were subjected to heavy extractive pressure since at least 1938 until 1960.…”