Mg. Diaz-Peralta, Christian

Growing coastal urbanization together with the intensification of maritime traffic are major processes explaining the increasing rate of biological introductions in marine environments. To investigate the link between international maritime traffic and the establishment of non-indigenous species (NIS) in coastal areas, biofouling communities in three international and three nearby local ports along 100 km of coastline in south-central Chile were compared using settlement panels and rapid assessment surveys. A larger number of NIS was observed in international ports, as expected in these ‘invasion hubs’. However, despite a few environmental differences between international and local ports, the two port categories did not display significant differences regarding NIS establishment and contribution to community structure over the studied period (1.5 years). In international ports, the free space could be a limiting factor for NIS establishment. The results also suggest that local ports should be considered in NIS surveillance programs in Chile.

La maricultura artesanal surge en las últimas décadas como una actividad productiva para el desarrollo socioeconómico de las islas del Golfo de Nicoya en Costa Rica. Determinar las condiciones ambientales y biológicas para impulsar el cultivo de Mytella guyanensis representa un gran insumo para el manejo y la comercialización de estos bivalvos de forma sostenible. Se evaluó el crecimiento, la mortalidad y su relación con los parámetros ambientales en un medio de cultivo en suspensión en Isla Chira. Durante 6 meses (octubre 2018-marzo 2019), se registraron los principales parámetros ambientales del medio de cultivo, se realizaron biometrías a 300 individuos de la población cultivada y, además, se estimó la tasa de mortalidad mediante el procesamiento de 60 canastas de mejillón. En términos generales, a) los parámetros físico-químicos monitoreados presentaron condiciones aptas para el cultivo de estos organismos, b) se registró una tasa de mortalidad del mejillón mensual promedio de 13 %±4,5; y c) M. guyanensis alcanzó un tamaño apto para su comercialización y consumo (≥40 mm de longitud) a partir del cuarto mes de cultivo. El crecimiento de M. guyanensis mediante el sistema de producción en canastas suspendidas, tiende a suceder con mayor rapidez con respecto a su crecimiento en bancos naturales. El futuro de la Maricultura, dependerá en gran medida del seguimiento de los parámetros físico-químicos, de la caracterización de rangos óptimos para las especies cultivadas, como también, de la identificación de nuevos sitios aptos para cultivar.

The spatial distribution of heavy metals content (Ba, Cd, Cu, Pb, Sr and Zn) in sediments of the Baker Fjord and surrounding channels in the central region of the Chilean fjords (47°45'S, 48°15'S) is analyzed. The aim of the study was characterized the patterns of abundance and distribution of these metals in surface sediments. The area corresponds to a poorly studied zone with low human activity. Distribution patterns would be influenced by rainfall conditions (local erosion), fluvial (continental sediments carried by rivers), glacier (glacier flour) and estuarine circulation. Cluster analysis allows differentiation among the sampled sites and group with similar characteristics. Finally, the concentrations found were contrasted with average values of metamorphic rocks and show with some certainty that the values found for calendar for this area and the greatest concentrations are the result of natural enrichment.

Biological invasions and changes in land and sea use are among the five major causes of global biodiversity decline. Shipping and ocean sprawl (multiplication of artificial structures at the expense of natural habitats) are considered as the major forces responsible for marine invasions and biotic homogenization. And yet, there is little evidence of their interplay at multiple spatial scales. Here, we aimed to examine this interaction and the extent to which the type of artificial habitat alters the distribution of native and non‐indigenous biodiversity. Location: Southeast Pacific—Central Chilean coastline.

Choosing an alternative species of mussel for the aquaculture industries, will be possible if it has equal or greater yield than the mussel cultivated. This study compares the growth of the chilean native mussel Mytilus chilensis with the non-native Mediterranean mussel Mytilus galloprovincialis and evaluate if environmental variables and cultivation depth affects mussels growth. Mussel were seeded in summer, with the same mean total weight and shell length for both species. At the end of the experiment, shell length (SL), condition index and gonadosomatic index were compared over month, depth and species. Highly significant differences were found in shell length between month and depth and between month and species (p < 0.05). The linear relationship between the gonad weight and wet meat weight in M. chilensis present a higher gonad weight for the same wet meat weight than M. galloprovincialis. It can be concluded that at the end of the harvest size cultivation M. chilensis presents a greater gonad weight, condition index and gonadosomatic index.

Non-native ascidians are important members of the fouling community associated with artificial substrata and man-made structures. Being efficient fouling species, they are easily spread by human-mediated transports (e.g., with aquaculture trade and maritime transports). This is exemplified by the ascidian Asterocarpa humilis which displays a wide distribution in the Southern Hemisphere and has been recently reported in the Northern Hemisphere (NW Europe). In continental Chile, its first report dates back from 2000 for the locality of Antofagasta (23_x000E_S). Although there was no evidence about the vectors of introduction and spread, nor the source, some authors suggested maritime transport by ship hulls and aquaculture devices as putative introduction pathways and vectors. In the present study, we report for the first time the presence of A. humilis on the hull of an international ship in a commercial port in Concepción bay (36_x000E_S), south central Chile. We also found one individual associated to a seashell farm, 70 km far from Concepción bay. Further individuals were subsequently identified within Concepción bay: one juvenile settled upon international harbor pilings and a dozen individuals along aquaculture seashell longlines. For the first specimens sampled, species identification was ascertained using both morphological criteria and molecular barcoding, using the mitochondrial gene cytochrome c oxidase subunit I (COI) and a nuclear gene (ribosomal RNA 18S). The nuclear 18S gene and the mitochondrial gene COI clearly assigned the specimens to A. humilis, confirming our morphological identification. Two haplotypes were obtained with COI corresponding to haplotypes previously obtained with European and Northern Chilean specimens. The present study thus reports for the first time the presence of A. humilis in the Araucanian ecoregion, documenting the apparent expansion of this non-native tunicate in Chile over 2,000 km, spanning over three ecoregions. In addition we reveal the potential implication of the international maritime transport as a vector of spread of this species along the Eastern Pacific coast, and the putative role of aquaculture facilities in promoting local establishments of non-native tunicates.