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Savoya, V.; Gómez Otero, J., and Schwindt, E., 2015. Toward a better understanding of the native-nonnative status of Mytilus mussels in the southwestern Atlantic: comparing pre-European middens and modern populations. The aim of this study is to determine the degree of similarity of the Mytilus mussels currently found along the Patagonian coast of Argentina to those found in pre-European colonization middens, in order to approach an understanding of whether the former are native or not. An elliptic Fourier analysis between pre-European archaeological (native) and modern mussels (cryptogenic) was performed, and the resulting data were analyzed with multivariate approaches (principal component analysis, discriminant function analysis, and cluster analysis). Our results showed that when all samples belonging to the Patagonian coast were included on a single analysis, modern and archaeological mussels were clustered in two major groups, matching the macroregional marine biogeographic scheme. In addition, morphometric differences were detected when modern and archaeological mussels from similar latitudes were compared. We discuss these results in light of the natural and anthropogenic changes that occurred along the Argentinean coast together with the environmental changes occurring between the biogeographic provinces along the SW Atlantic coast. El objetivo del presente trabajo es realizar un estudio morfológico entre valvas de mejillones Mytilus actuales y arqueológicos de la costa patagónica de Argentina, a fin de brindar una nueva perspectiva que permita mejorar el conocimiento sobre el origen nativo o invasor de los mejillones Mytilus actuales. Valvas arqueológicas (nativas) y actuales (criptogénicas) se estudiaron mediante el análisis elíptico de Fourier, y los datos obtenidos se analizaron con análisis multivariados (análisis de componentes principales, análisis de función discriminante, análisis de conglomerados y MANOVAs). Por un lado, los resultados muestran que en un análisis conjunto de todas las muestras ( i.e. actuales y arqueológicas) éstas se agruparon siguiendo el esquema biogeográfico del mar argentino. Por otro lado, las valvas actuales y arqueológicas procedentes de latitudes similares de la costa patagónica se diferenciaron morfométricamente. Los resultados se discuten a la luz de los cambios naturales y antropogénicos ocurridos a lo largo de la costa argentina, y considerando además las diferencias ambientales entre ambas provincias biogeográficas del mar argentino. [ABSTRACT FROM AUTHOR]

Seaweed invasions are recognized as one of the major threats to biological diversity and coastal resources. Nevertheless, the number of introduced macroalgae has been underestimated due to the increasing number of cryptic invasions. Polysiphonia morrowii is native to the North Pacific and several cryptic introductions of this species have been reported over the past decade. In this study, we recorded the presence of the invasive P. morrowii in the Southwestern Atlantic (Patagonia Argentina) using a morphological and molecular approach for the identification at species level. Polysiphonia morrowii specimens from Argentina showed no morphological differences from members of invasive populations in France. We found two different haplotypes, suggesting that P. morrowii was probably introduced into this area by multiple introduction events. The increasing number of shipping and aquaculture activities worldwide and the ability of this species to be a successful invader suggest that P. morrowii is likely to be a cosmopolitan invasive species and that further management planning is required for its early detection and control. [ABSTRACT FROM AUTHOR]

Ports are a key factor in the understanding and solving of most problems associated with marine invasive species across regional and global scales. Yet many regions with active ports remain understudied. The aim of this work was to (a) identify and quantify the marine fouling organisms in all Patagonian ports of Argentina classifying them as native, exotic or cryptogenic species through a rapid assessment survey and experimental studies, (b) survey the environmental and anthropogenic variables of these ports and (c) analyze and discuss these results in the light of the South America context for the study of marine invasive species, legislation and commerce. We found 247 fouling species, including 17 introduced, one of which is a new record for the region, and other 15 species currently considered cryptogenic species that will need further attention to clarify their status. The analysis of mobile and sessile taxa, together with the environmental variables measured in this study and the port movement, allow us to discuss individual ports' vulnerability to future introductions. This is the first large scale study performed for this region on this topic, and it will help in developing monitoring programs and early detection plans to minimize new species introductions along the marine coastline of southern South America., (Copyright © 2014 Elsevier Ltd. All rights reserved.)