Dr. Brante-Ramírez, Antonio

Genetic structure and connectivity information can be used to identify biological corridors and prioritize the conservation of areas that help maintain ecosystem integrity. Some marine fish, especially those of commercial interest, have been proposed as suitable indicators to identify potential marine biological corridors due to their high mobility among habitats and socioeconomic importance. In this study, we assessed the genetic structure of lane snapper populations in the Honduran Caribbean to evaluate connectivity and identify potential environmental barriers. Furthermore, we evaluated the genetic characteristics of the lane snapper on a larger spatial scale, including populations across the rest of its distribution range in the western Atlantic, using mtDNA and nuDNA markers. Our results demonstrate a significant genetic diversity of lane snappers in the Honduran Caribbean. Furthermore, despite their high dispersal potential, we observed genetic structuring in lane snapper populations on a larger spatial scale, resulting in the formation of two distinct groups throughout their distribution range: group 1 from Florida, the Gulf of Mexico, Honduras, and Colombia and group 2 from Puerto Rico and Brazil. This genetic differentiation can be attributed to oceanographic barriers such as river plumes and marine currents. These findings have the potential to significantly impact marine conservation and management efforts in the region, both at local and regional scales. It is anticipated that they will not only inform but also elicit a response, driving further action towards effective conservation measures. At a local scale, we recommend that conservation efforts focus on protecting critical habitats. At a regional scale, lane snappers should be included in the management plans of existing marine protected areas necessary to ensure the long-term sustainability of the species and the marine ecosystems in which it resides.

Gorgonians (like corals) are important habitat-forming organisms that support a diversity of macrofauna. This study explored structural attributes of gorgonian gardens formed by rose gorgonians (Leptogorgia sp. nov.) and associated macrofaunal assemblages in Caleta Pichicuy (Central Chile). Hierarchical sampling was conducted at 20 m depth (maximum colony abundances) in order to assess spatial variability in abundance and colony attributes at two spatial scales (among sites and rocky walls). The abundance and composition of the associated vagile and sessile macrofauna were also examined using univariant (Taxa richness and Shannon index (H’e)) and multivariant approaches and were compared with adjacent bare rocky habitats. Our results showed a high abundance of gorgonians (ca. 28.9–36.5 colonies m−2) compared to other gorgonian gardens in the world. For structural attributes, our results showed smaller colonies with thicker holdfasts in more exposed sites, suggesting the influence of hydrodynamic forces on the colony morphology. Taxa richness and H’e of vagile fauna showed threefold and twofold, respectively, higher values in gorgonian gardens compared to bare walls, but no differences were observed for sessile fauna. In addition, PCoA and PERMANOVA evidenced a distinctive assemblages’ composition between habitats for both vagile and sessile fauna. Correlation analyzes and dbRDA showed, however, little association between structural attributes and associated faunal assemblages (R2 = 0.06, and ca. 3–9.4% of the total variation explained, respectively). Our results constitute the first assessment of structural habitat complexity and accompanying fauna in these gorgonian gardens and establish the baseline for understanding possible future changes associated to human activities.

Las especies del género Anisakis (Nematoda: Anisakidae) son parásitos marinos con ciclo de vida indirecto. Los crustáceos planctónicos actúan como primeros hospedadores intermediarios, mientras que peces y cefalópodos intervienen como segundos hospedadores intermediarios o paraténicos, finalmente el ciclo se cierra en los cetáceos, mamíferos marinos que son los principales hospedadores definitivos del género. En el ciclo de vida, las larvas de Anisakis pueden ser ingeridas por el hombre interviniendo como huésped accidental, lo que puede ocasionar anisakiasis, una zoonosis adquirida a través del consumo de peces y cefalópodos crudos o marinados. Estos nemátodos tienen una distribución cosmopolita, sin embargo, su diversidad ha sido escasamente estudiada en el hemisferio Sur. Por tanto, se evaluó la diversidad de las larvas de Anisakis spp., presentes en dos especies de hospederos de Chile, combinando el análisis morfométrico y genético. Para ello, se recolectaron larvas de Anisakis spp. en la cavidad abdominal de la merluza Merluccius gayi y el calamar Dosidicus gigas, procedentes de terminales pesqueros de la región del Biobío, Chile. La caracterización morfométrica de las larvas de Anisakis spp., consistió en la medición de la longitud del esófago, ventrículo esofágico, cola, longitud total y ancho máximo del cuerpo. Para los análisis genéticos se usó la región molecular nuclear ITS (ITS1-ITS2) y mitocondrial COX2. Los resultados morfométricos revelaron que las larvas extraídas de D. gigas son significativamente de mayor longitud que las recolectadas en M. gayi, sugiriendo una alta variabilidad fenotípica hospedador-dependiente. Los análisis moleculares y filogenéticos determinaron la presencia de Anisakis pegreffii en ambos hospedadores, sin embargo, demostraron una baja diferenciación genética y diversidad nucleotídica entre las secuencias, indicando una escasa variabilidad genética para el conjunto de datos. Este trabajo constituye el primer registro molecular de A. pegreffii en hospedadores intermediario o paraténicos de la costa de Chile.

The introduction and establishment of invasive species in regions outside their native range, is one of the major threats for the conservation of ecosystems, affecting native organisms and the habitat where they live in, causing substantial biological and monetary losses worldwide. Due to the impact of invasive species, it is important to understand what makes some species more invasive than others. Here, by simulating populations using a forward-in-time approach combining ecological and single polymorphic nucleotides (SNPs) we evaluated the relation between propagule size (number of individuals = 2, 10, 100, and 1,000), extinction rate (with values 2%, 5%, 10%, and 20%), and initial heterozygosity (0.1, 0.3, and 0.5) on the population survival and maintenance of the heterozygosity of a simulated invasive crab species over 30 generations assuming a single introduction. Our results revealed that simulated invasive populations with initial propagule sizes of 2–1,000 individuals experiencing a high extinction rate (10–20% per generation) were able to maintain over 50% of their initial heterozygosity during the first generations and that under scenarios with lower extinction rates invasive populations with initial propagule sizes of 10–1,000 individuals can survive up to 30 generations and maintain 60–100% of their initial heterozygosity. Our results can help other researchers better understand, how species with small propagule sizes and low heterozygosities can become successful invaders.

The intertidal mussel Perumytilus purpuratus exhibits phenotypic plasticity in response to predation threats, with these responses influenced by the mussels' perception of predation risk. These adaptations, however, are constrained by energy costs and interactions with environmental factors that may trigger synergistic effects or trade-offs among different fitness traits. In particular, this study focuses on the anti-predatory responses of P. purpuratus against the sea star Meyenaster gelatinosus, examining how the presence of the predator and water flow strength influence these responses. The research was conducted through laboratory experiments, comparing mussels from two distinct localities with varying predation risks posed by M. gelatinosus: Punta Hualpén, where the predator is naturally present, and Coliumo, where it is absent. The anti-predatory responses were assessed by measuring attachment strength, byssus production, and adductor muscle mass in the presence of predator cues. Additionally, potential costs associated with these responses were estimated using the gonadosomatic index as a measure of reproductive investment. The findings indicate that the anti-predatory responses of P. purpuratus are contingent on the mussel's origin, with adhesion strength and byssus production negatively impacting reproductive investment. Moreover, the study highlights the intricate interplay of multiple factors, as evidenced by the complex adaptive mechanisms observed in P. purpuratus. The interaction between predator presence and water flow strength and their combined effects on various traits underscores the need for comprehensive multifactorial experiments to understand these adaptive processes. In conclusion, this study provided valuable insights into the nuanced and site-specific nature of anti-predatory responses in P. purpuratus. The research emphasizes the importance of considering multiple factors and conducting comprehensive experiments to unravel the intricacies of adaptive mechanisms in prey species.

Aim: Trait‐based approaches are powerful to examine the processes associated with biological invasions. Functional comparison among native and non‐indigenous species (NIS) can notably infer whether novel assemblages result from neutral or niche‐based assembly rules. Applying such a framework to biofouling communities, our study aimed to elucidate their distributions within two marine urban habitats (namely floating vs. nonfloating habitats). Location: Southeast Pacific—Central Chilean coastline. Methods: Here, we examined the distribution of 12 functional traits in fouling communities established on settlement plates, after 3 and 13 months of deployment in the two habitats and across ports in Central Chile. Based upon previously described differences of assemblages and NIS contribution across habitats, we hypothesized that nonindigenous, cryptogenic and native taxon pools would be functionally distinct (and trait biased), and that functional diversity and structure would vary across habitats and successional stages. Results: Our results show, as anticipated, that nonindigenous (13 taxa), cryptogenic (12) and native (18) taxon pools are functionally distinct, though overlapping in the trait space. Non‐indigenous species are rather related to colonizing traits, while native species are more related to competitive traits. Only one widespread NIS was functionally similar to the late successional and most competitive native species, including taxa elsewhere invasives. Despite differences in taxonomic composition between habitats, we did not observe functional differences between them. In contrast, temporal variations across colonization stages were detected along with an increased contribution in large and long‐lived taxa, together with site‐specific trajectories. Main Conclusions: We conclude that the functional distinctness among nonindigenous, cryptogenic and native taxa occupying artificial habitats in ports reflects niche‐based processes. Site‐specific trajectories indicate that scale‐dependent assembly processes, such as dispersal and species interactions, are at play.

Non-indigenous species have been widely recognized as major drivers of biodiversity loss. However, management in marine ecosystems entails particular challenges of detection and control, with an approach which requires stakeholders from the government, academia and the public. To generate a first approach to what should be the national Chilean agenda for non-indigenous species (NIS) management, a workshop was convened at the Universidad Católica del Norte in Coquimbo on the past, present and future of marine bioinvasions in Chile. The workshop, with more than 60 participants, including academics and public services, gathered information from the published literature on the state of the art of marine bioinvasions in Chile and proposed a work agenda for the coming years. The results highlight that the design and implementation of more focused and effective management policies and programs will be required to potentially reduce the rates of new invasions and identify mitigation strategies. We present the first proposed NIS research and management agenda for Chile developed through a collaborative process between researchers and the Chilean government, with a joint vision of both the challenges and solutions.

Ship hull fouling is recognized as an important vector for the introduction of nonindigenous species (NIS), which has been studied globally but no empirical works exist in the Southeast Pacific. The present study examined fouling organisms on the hulls of three ships in one international Chilean port, and compared them with those on settling plates and natural substrates. Also, genetic analyses were perfomed on the most common NIS recorded in order to explore number and potential origin of the genetic linages found. The highest number of total taxa and NIS were found on ship hulls, with three species identified as NIS in ship samplings. Settling plates displayed the largest number of taxa, with a large abundance of the invasive tunicate Ciona robusta, which also showed high mitochondrial genetic diversity. This study showed that Chilean coasts are subjected to both NIS colonization and propagule pressure through ship hulls. Biosecurity measures should urgently be taken on ship hulls along these coasts.

Non-native species can have profound implications on the survival of native ones. This is especially true for some invasive crabs, such as the green crab Carcinus maenas, a native species to the Northern Hemisphere that has been introduced into southern Argentina, from where it could expand through Argentina, Chile, and the Antarctic Peninsula. Hence, there is interest in forecasting changes in C. maenas habitat suitability through time to predict if potential future invasions might occur. Here, by using a Species Distribution Model (SDM) approach, we estimated the habitat suitability for C. maenas along southern South America and the Antarctic Peninsula under two future climate-change scenarios. Our results reveal that under current conditions, habitat suitability for C. maenas along the Antarctic Peninsula is null and very restricted in Argentina and Chile. Habitat suitability along the Antarctic Peninsula remained null in the short-term (30 years) and long-term future (80 years), despite the climate-change scenario considered. Surprisingly, when considering future conditions, habitat suitability along the coast of Argentina and Chile decreased and became nil for some currently occupied locations. Thus, the SDM results suggest that climate change could have a negative effect on the habitat suitability of C. maenas leading to potential local extinctions.

Natural disturbances can modify extinction-colonization dynamics, driving changes in the genetic diversity and structure of marine populations. Along Chilean coast (36°S, 73°W), a strong hypoxic-upwelling event in 2008, and a mega earthquake-tsunami in 2010 caused mass mortality within the Aphos porosus population, which is a vulnerable species with low dispersal potential. We evaluated the effects of these two major disturbances on the diversity and spatial-temporal genetic structure of Aphos porosus in two neighboring areas that were impacted on different levels (High level: Coliumo Bay; Low level: Itata Shelf). Thirteen microsatellites (from 2008 to 2015) amplified in individuals collected from both locations were used to evaluate the effects of the two disturbances. Results showed that after the strong hypoxic-upwelling event and the mega earthquake-tsunami, Aphos porosus populations exhibited lower genetic diversity and less effective population sizes (Ne < 20), as well as asymmetries in migration and spatial-temporal genetic structure. These findings suggest a rise in extinction-recolonization dynamics in local Aphos porosus populations after the disturbances, which led to a loss of local genetic diversity (mainly in Coliumo Bay area impacted the most), and to greater spatial-temporal genetic structure caused by drift and gene flow. Our results suggest that continuous genetic monitoring is needed in order to assess potential risks for Aphos porosus in light of new natural and anthropogenic disturbances.