Bioinvasion threatens the genetic integrity of native diversity and a natural hybrid zone: smooth-shelled blue mussels (Mytilusspp.) in the Strait of Magellan

Abstract

Smooth-shelled blue mussels of the Mytilus edulis species complex are widely distributed bivalve molluscs whose introductions threaten native marine biodiversity (non-indigenous species -NIS). The aim of the present study was to identify the species and hybrids of Mytilus present in the Magellan Region (southern Chile). Results indicate that three mussel species of the Mytilus edulis complex are found in the region -M. edulis, M. chilensis (or the Southern Hemisphere lineage of Mytilus galloprovincialis), and M. galloprovincialis of Northern Hemisphere origin. For the first time, alleles of the introduced M. trossulus are reported from the Southern Hemisphere. In the Strait of Magellan the native Pacific blue mussel, Mytilus chilensis and the native Atlantic blue mussel, Mytilus edulis, meet and mix at a natural hybrid zone (about 125 km in length). This is the first record of a natural Mytilus hybrid zone in the Southern Hemisphere and is also the first record of the cooccurrence of genes from all four Mytilus species in any one region. These results contribute to the knowledge of the biodiversity and delimitation of mussel species in southern South America, and highlight how introduced species may threaten the genetic integrity of native species through hybridization and introgression.

Native and invasive taxa on the Pacific coast of South America: Impacts on aquaculture, traceability and biodiversity of blue mussels (Mytilus spp.)

“…Although the distributions of these taxa have been studied extensively in the Northern Hemisphere, in the Southern Hemisphere taxon distributions do not always fit the classical “ Mytilus edulis complex” scheme. Whilst we have a better (but still not completely resolved) understanding of the situation in Australia and New Zealand (Ab Rahim et al., ; Gardner et al., ; Westfall and Gardner, , ), the situation in South America still requires resolution (Gaitán‐Espitia, Quintero‐Galvis, Mesas, & D'Elía, ; Oyarzún, Toro, Cañete, & Gardner, ).…”

“…Production is concentrated in the Gulf of Reloncaví and along the coastline of Chiloé Island (Los Lagos region) and is based on the native blue mussel, nominally Mytilus chilensis . However, other species in Chile have also been reported, including M. galloprovincialis in the Gulf of Arauco–Bío‐Bío region (Astorga et al., ; Daguin & Borsa, ; Tarifeño et al., ; Westfall & Gardner, ) and M. edulis in the Strait of Magellan–Magallanes region (Oyarzún et al., ), although this last species is named as M. platensis by Gaitán‐Espitia et al. ().…”

Modelling long-term recruitment patterns of blue mussels Mytilus galloprovincialis: a biofouling pest of green-lipped mussel aquaculture in New Zealand

“…1A), the native New Zealand blue mussel Mytilus galloprovincialis (hereafter My tilus) has been a persistent and wide-spread biofouling problem for several de cades. This species is part of the Mytilus edulis complex (Westfall & Gardner 2010, Oyarzún et al 2016. It represents a Southern Hemisphere lineage of the Mediterranean mussel Mytilus galloprovincialis, with evidence of extensive hybridisation and backcrossing between New Zea land blue mussels and the invasive Northern Hemisphere lineage of M. galloprovincialis .…”

Complete female mitochondrial genome of Mytilus chilensis

“…The status of these populations remains controversial. Some researchers call them either M. edulis or M. galloprovincialis of southern hemisphere (Westfall & Gardner 2010), while others use the term M. chilensis (Oyarz un et al 2016). The officially accepted classification gives the native South American Mytilus mussels subspecies rank and the name M. edulis platensis d'Orbigny, 1842 and is supported by a critical review of literature (Borsa et al 2012).…”

“…The officially accepted classification gives the native South American Mytilus mussels subspecies rank and the name M. edulis platensis d'Orbigny, 1842 and is supported by a critical review of literature (Borsa et al 2012). It has been speculated that as many as four Mytilus species are present in the Magellane region of Chile (Oyarz un et al 2016). Unfortunately, these are based on a limited number of nuclear and low resolution mitochondrial markers.…”