Pacific Coast Of South America Research Articles

Spatial and temporal variability of wave energy resource in the eastern Pacific from Panama to the Drake passage

We analyse the wave energy resource available along the Pacific coast of South America from Panama from the latitude of 8°N to the Drake Passage at 55°S. The analysis is based on wave time series over 63 years (1959–2021) from the European Union Copernicus database constructed using the WAM wave model for the entire Pacific forced by wind information from ERA5. The novel features are the analysis of temporal variations in the wave energy flux, quantification of the contribution of swells and wind-seas into the wave energy potential, establishing properties of the most energy-carrying wave conditions, and evaluation of the role of El Niño and La Niña in the wave energy potential. The annual average wave energy flux increases from about 2 kW/m just to the north of the equator on the Colombian Pacific coast to 20–50 kW/m in the central and southern mainland of Chile and up to 80 kW/m near the Drake Passage. The wave energy resource to the north of latitude 32°S is almost entirely provided by swells. To the south of 44°S wind-seas predominate among the most energetic wave conditions and the maxima of energy flux by wind-seas up to 20 times exceed the already high average energy flux. The temporal variation in the wave energy flux follows the same pattern. It is fairly small at lower latitudes and increases rapidly from the forties. The magnitude of seasonal variation in terms of monthly mean wave energy flux is commonly from −47% to +32% from the long-term mean. The calmest time that contains 1% of the total annual energy flux is 10–20 days, about 10% of energy is contained in the 100 calmest days, while 50% of the annual energy flux arrives during the 100 days with strongest waves in the entire study area. The typical height of waves that provide the largest contribution to wave energy is about 1–1.5 m in the very north, around 1 m near the equator, gradually increases to the South and reaches 3.5–4 m on the shores of southern Chile. The associated wave periods are about 10 s in the entire study area. The wave energy flux has been almost constant over the 63 years near the equator but has increased at a rate up to 0.6 kW/m per year in the nearshore of Chile. For the evaluated time scales in coastal areas of South America, the interchange of El Niño and La Niña does not have detectable impact on the wave energy resource.

The Russian Archaeological Project in South America: Principal Findings and Prospects

This study outlines the findings of field and laboratory studies by the first Russian archaeological expedition to South America in 2014–2015 and 2017–2018 in collaboration with colleagues from Ecuador and Japan. The project focused on sites of the Archaic (10.8–6.6 ka BP) and Early Formative period (5.5–3.5 ka BP) in the coastal zone of Santa Elena Province, Ecuador. Excavations at Real Alto (Valdivia culture) and Loma Alto (Las Vegas culture) yielded representative archaeological, anthropological, and faunal samples and a large series of AMS dates, providing a basis for a number of novel proposals regarding the chronology and periodization of cultures, their origin, and early pottery-production in South America. Specifically, we have demonstrated that at the very beginning of the Formative period, two early ceramic traditions coexisted—Valdivia and “San Pedro”. We have demonstrated the peculiarity of the “Tropical package” in the stone toolkit, and traced the previously unknown features of the funerary rites of the Las Vegas and Valdivia cultures. Radiocarbon analysis helped to correct the chronology of the late stage of the pre-ceramic Las Vegas culture (8.0–4.8 ka BP) and to estimate the tentative date of the earliest pottery manufacture at 4.8–4.7 ka BP. In conclusion, we outline the top priorities and prospects of Russian archaeological studies on the Pacific coast of South America, underscoring the importance of international cooperation.

The use and context of fiber plants during the middle preceramic: evidence from La Yerba II and III, south coast of Peru

Bast fiber artifacts from the Pacific coast of South America are among the earliest evidence of fabric manipulation and the foundation of the millennial Andean textile tradition. Recent examinations of plant macro remains and plant fiber artifacts from La Yerba II (7570–6674 cal BP) and La Yerba III (6485–5893 cal BP) sites provide insight into how plant fabric technologies and pre-loom textile traditions unfolded over the Middle Preceramic (or Middle Archaic; 8000–5000 BP) on the south coast of Peru. Using light microscopy and scanning electron microscopy (SEM), we conduct comparative analyses of modern and archaeological plants to assess the taxonomy and morphological distinctions between them to discriminate species. We identify materials from wild-gathered plants in the Cyperaceae, Typhaceae, and Apocynaceae families and show how they were used to make fishing nets, looped bags, mats, and other artifacts. Evidence from tools and cut marks also enabled us to reconstruct parts of the chaîne opératoire of the fiber production. We discuss the significance of plants from wetland and estuarine habitats in the interrelated dimensions of fabric manufacture and food consumption among these coastal hunter-gatherers.

Deciphering Permanent Uplift Along the Pacific Coast of South America Through Signal Analysis of Various Tectonic Processes

AbstractThe tectonically active South American margin is characterized by the accumulation of deformation contributing to uplift of the Andean forearc at millennial time scales. However, the mechanisms responsible for permanent coastal uplift are debated, mainly because methodologically consistent, continental‐scale analyses of uplifted terraces have not yet been carried out for South America. Uplifted marine terraces are generally used to infer permanent coastal deformation and uplift; we used almost 2,000 measurements of last‐interglacial marine terraces to calculate an uplift‐rate signal on which we performed a wavelength analysis. The same spectral analysis was applied to tectonic and subduction parameters associated with accumulation of permanent deformation to detect possible links with the uplift‐rate signal. The uplift‐rate signal displays a constant background‐uplift rate along the margin, perturbed by changes at variable wavelengths. Similarities between its wavelength spectrum and the spectra of tectonic parameters suggest potential correlations pointing toward underlying processes. For example, crustal faulting is mainly responsible for short‐wavelength deformation; intermediate‐wavelength to long‐wavelength tectonic features indicate various extents of locked areas on the megathrust that relate to its long‐term seismotectonic segmentation. We suggest that moderate, long‐term background uplift is caused by major, deep earthquakes near the Moho, although records of such events are sparse. Due to their disparate occurrence, we infer accumulation of permanent deformation over millennial time scales through multiple, distinct uplift phases that are spatially and temporally distributed. Our study highlights the application and utility of a signal‐analysis approach to elucidate the mechanisms driving surface deformation in subduction zones at a continental scale.

Rediscovery of a humpback whale (Megaptera novaeangliae) feeding ground in the Straits of Magellan, Chile

New information is presented on the summer distribution of southeastern Pacific humpback whales along the Southern Chilean fjords. Sightings of 128 humpback whales observed between December and June from 1997-2001 were analysed. Sightings occurred between 48°50AS to 54°18AS and were concentrated in the waters surrounding Isla Carlos III in the Straits of Magellen (53°37AS, 72°21AW) and in the Canal Wide (49°36AS–5°S). To date, 23 individual whales have been identified from photographs of the ventral surface of the flukes. Throughout the austral summer, seven individuals were resighted near Isla Carlos III over periods between 2-5 months. Two individuals were observed in 1999 and 2000, and two individuals were previously recorded in 1997 in Canal Wide, about 365km north of Isla Carlos III. Historical records show the occurrence of whales in the area from the 16th to the 20th Century. From historic records, scattered whaling data, the small amount of scientific literature available, and the results of this study, it is suggested that the southwestern part of the Straits of Magellan, especially the waters surrounding Isla Carlos III, is the first known feeding ground for humpback whales along the Pacific coast of South America.

The late Cenozoic evolution of the Humboldt Current System in coastal Peru: Insights from neodymium isotopes

The Humboldt Current System along the Pacific coast of South America creates one of the most productive ecosystems on Earth. To trace the origin of the water masses in this area, we measured neodymium isotope compositions (ԑNd) in tooth enameloid of two genera of coastal sharks from latest Oligocene to early Pleistocene strata in the Pisco and Sacaco basins in southern Peru. Most ԑNd values range from −4 to −1, with a strong negative excursion in the late Miocene (∼8–7 million years ago [Ma]) with values as low as −9.2. The overall trend of the ԑNd values resembles that of equatorial Pacific deep waters, though with an offset of about +2 ԑNd units until about 6 Ma. With a major input of hinterland weathering considered unlikely, we interpret this pattern as reflecting a modern-type upwelling regime, though with a lower contribution of Antarctic waters than today. Starting about 6 Ma, the contribution of Antarctic waters to the upwelling waters increased approximately to present-day levels, coincident with, and possibly driven by, increased Antarctic glaciation and the Andes reaching their present-day elevation, both of which likely enhanced the counter-clockwise circulation in the South Pacific Ocean. The negative excursion of ԑNd values in the Pisco/Sacaco basins ∼8–7 Ma coincides with a late Miocene biogenic bloom in the Pacific Ocean and elsewhere, and with a strongly increased northward bottom current observed on the Nazca Drift System just offshore our sampling area. Thus, the negative excursion of ԑNd values in the Pisco/Sacaco basins likely resulted from a southern sourced input of nutrient-rich, unradiogenic water, which could have been an important contributor to the biogenic bloom.

Seasonal dynamics in the inner Guayas Estuary, Ecuador

The Guayas estuary in Ecuador is the largest estuarine ecosystem on the Pacific coast of South America. This estuary provides nurseryand fisheries habitats, as well as filtering and detoxification services provided by suspension feeders, vegetation, and wetlands. Weused oceanographic and meteorological observations to understand the hydrodynamic variability of two areas in the inner part ofthe estuary, Manglares de Churute and Estero Salado, from February 2016 to February 2017. Churute has less anthropogenic impacts thanEstero Salado, which is currently uncoupled from river flow and highly influenced by Guayaquil, the second largest city in Ecuador, andadjacent shrimp pond effluents. The influences from the ocean and river on Churute include higher dissolved oxygen (DO) and lower salinity,temperature and phosphates than in Estero Salado, particularly during the wet season when the river is the dominant mode of forcing inthose warm and rainy first months of the year. Hypoxic levels (DO below 2 mg L-1) were found in Estero Salado in several stations duringthe hot, rainy season. These data suggest seasonal variability (dry/rainy season) influences the hydrographic conditions in the inner Guayasestuary mostly, adding variability to salinity, turbidity, nutrients and DO of the whole water column.

Fog as unconventional water resource: Mapping fog occurrence and fog collection potential for food security in Southern Bolivia

“Valles Cruceños” rural region, Bolivia, is characterized by intrinsic water scarcity and increasing pressure for food production by the neighboring and fast-sprawling city of Santa Cruz de la Sierra. Here, orographic fog is a phenomenon occurring all year round, representing a sustainable water source for improving farmers’ resilience to dry spells and for promoting food security and sovereignty. With the present study, we aim at a first assessment of the potential of fog collection in the area by a 1-year experimental analysis made through 1-m2 fog collectors in 10 different locations. Starting from these data, we design under safe assumption (including sensitivity analysis) a fog water irrigation system providing water for a standard theoretical field with four local crops (maize, green beans, potato, and tomato) in the dry season. The present paper represents the first study on fog collection in Bolivia, showing that, on annual basis, an average of 6.01 l/m2/d can be obtained from most productive areas, with peaks up to 8.93 l/m2/d. Moreover, to the best of our knowledge, the work represents one of the first consistent studies on the productive use of orographic fog, while a large part of the literature focuses on advection fog, mostly occurring on the Pacific Coast of South America.

An Inca Tern in the Hawaiian Islands: First Record for Hawaii and the United States

An Inca Tern (Larosterna inca) was observed and photographed at several locations in the Hawaiian Islands from 10 March 2021 to 8 January 2022, constituting the northernmost and westernmost record for this species, which breeds on the Pacific coast of South America, and the first for the United States. Here I provide details about the appearance and inter-island movements of this individual, along with evidence indicating that only a single individual was involved in all sightings. The Hawaiian Islands occurrence, along with recent documentation of the Inca Tern in Central America north to Guatemala, points to yet another South American seabird moving north with increasing frequency in the Pacific Ocean.

First Record of the Exotic Caprellid Paracaprella pusilla (Amphipoda, Caprellidae) in the Peruvian Coast

Study of small-sized or taxonomically challenging taxa is mandatory to early detect exotic species. The caprellid Paracaprella pusilla has been successfully spreading in many world areas in the last decade. Biofouling from culture lanterns of bivalves Argopecten purpuratus and Pteria sterna were collected between February 2017 and November 2018 in Samanco Bay and Sechura Bay, Peru. This study represents the first record of P. pusilla in Peru, confirming that the species is expanding towards lower latitudes along the Pacific coast of South America. Paracaprella pusilla was found mainly associated with the bryozoan Bugula neritina and hydrozoan Ectopleura cf. crocea. The present study contributes to the knowledge of the biodiversity of these crustaceans in the Peruvian coast, but it is recommended to increase sampling along the Southeast Pacific.

A cryptic species of Ensis (Bivalvia: Pharidae) from the southeastern Pacific coast revealed by geometric morphometric methods

A new cryptic species of Ensis from the Pacific coast of South America based on geometric morphometrics is revealed. Ensis macha (Molina, 1782) is one of the most important shellfish resources in South America. It was historically reported from San Matías Gulf, Argentina in the Atlantic Ocean to the Peruvian coast in the Pacific. A recent study analysed the intraspecific variation of this species along its distribution range and the genetic results indicated the presence of cryptic diversity. Two evolutionary clades were found: a southern clade (from cold-temperate waters) and a northern clade (from warm-temperate waters). New results based on geometric morphometrics supported the description of Ensis loboi n. sp. for the northern clade. The southern clade retains the name due to type locality of E. macha in Chiloé, Chile. The description of Ensis loboi n. sp. for the southeastern Pacific Ocean has important implications for future studies focused on fisheries management and biogeographical radiation of the group.

Georoutes as a Basis for Territorial Development of the Pacific Coast of South America: a Case Study

Thematic travel itineraries (e.g. architectural, archaeological, geological routes) can be instrumental in developing tourism in a given area. Travellers are expected to follow the itineraries to visit natural, cultural, historical, or religious places. This work aims to propose three geological routes (georoutes) in the Santa Elena province as a base for geotourism development. The methodology includes (i) the compilation of a geosite inventory that covers geosites and sites of industrial interest; (ii) the proposal of georoutes (GR-I, GR-II, and GR-III); (iii) the evaluation of the proposed routes through the Geotouristic Route Assessment (GtRAM) method and the study of reception capacity of the territory; (iv) the description of strategies for local geotourism development based on a SWOT analysis. The GtRAM method yields “average” values for all of the proposed routes (2.16/5, 2.68/5, and 2.74/5 for routes GR-I, GR-II, and GR-III, respectively). According to the reception capacity study, 85.2% of the geosites are in intrinsic use and are compatible with the proposed activities; therefore, the environmental impact of the georoutes is expected to be low. The SWOT analysis revealed that geotourism development is possible if based on strategic planning. In conclusion, the proposed georoutes will complement local economic activities, and thus contribute to local development.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12371-022-00711-x.

Prehistoric reef-building coral occurrence in north Peru

Discovery of a late Pleistocene (∼13,300 cal BP) reef-building coral species (Pocillopora damicornis) at the prehistoric Huaca Prieta settlement in Peru raises the question of its origin. Did it arrive in northern Peru from tropical Ecuador via larval dispersal in south-flowing El Niño currents or over land by human trading? The Holocene distribution of Pocillopora in the eastern Pacific extends as far south as southern Ecuador and possibly northern Peru. The marine climate during the late Pleistocene was cooler and likely limited the occurrence of corals at today’s latitudinal range. This suggests that overland or onshore transport was the most likely means of a southerly introduction, thus supporting interpretative models of early human movement along the Pacific coast of South America.

Insights into changing coastlines, environments and marine hunter-gatherer lifestyles on the Pacific coast of South America from the La Yerba II shell midden, Río Ica estuary, Peru

Shell middens are conspicuous manifestations of the exploitation of rich, sustainable, easily seen and harvested marine resources that, worldwide, enabled hunter-gatherers to reduce mobility and increase population and social complexity. Globally, known sites tend to cluster chronologically around 6 k BP, after slowing eustatic sea-level rise, although the Pacific coast of South America offers some rare earlier exceptions.We report investigations of La Yerba II, a Middle Preceramic shell matrix site on the Río Ica estuary, south coast Peru. These show how, beginning around 7000 Cal BP, over 4.5 m of stratigraphy accumulated in less than 500 years. Consisting of prepared surfaces, indurated floors and the ashy interiors of wind shelters and their associated midden deposits, alternating with phases of abandonment, this was the outcome of an intense rhythm of repeated occupations by logistically mobile marine hunter-gatherers. Final phases, dominated by Mesodesma surf clams, mark change towards more task-specific activities.La Yerba II's topographic position and well-preserved cultural and environmental markers provide insight into the local history of relative sea level change and changing marine hunter-gatherer lifestyles during a period critical to the transition to sedentism and the formation of new estuarine and beach habitats following the stabilisation of eustatic sea-levels.

The World in a City: Multiethnic Radicalism in Early Twentieth-Century Los Angeles

In The World in a City David Struthers outlines the “world” of organizing that the radical Left made in Los Angeles, in networks across the western United States, and into Mexico. Struthers's contribution to labor history lies in his attention to the more pervasive “practice” of a “culture of affinity” in the daily activities and networks of the radical Left. Practices formed a shared culture, which in turn contributed to the organization of interracial, multi-lingual, international coalitions. Anarchists, syndicalists, and trade unionists of the Los Angeles radical Left moved in and out of formal and informal associations, sometimes lasting only as long as specific workplace struggles. Other organizations endured throughout the early twentieth century, as with the International Workers of the World or the Partido Liberal Mexicano (PLM). Organizers sought to teach anarchist ideals and to pass on tactics that workers could use in response to the specific conditions of labor that they experienced. Thus, the radical Left in Los Angeles was intentionally temporary, impermanent, constantly forming and reforming. Because direct action, rather than political reform of the state, was the goal, universalizing narratives of class equality and deliberate formation of community through a shared culture were more necessary.While these were the ideals that informed the affinities diverse workers created, interracial and multi-ethnic coalitions were frequently riven by common-sense assumptions about members of ethnic groups as conforming to racial types. Japanese workers were too well organized—and workers were believed to be organizable according to their racial characteristics. Mexican laborers were uneducated. Indigenous people were childlike and ignorant of the modern world. Anglos most often expressed such conceptions, but racialization occurred between non-whites as well. Most significant during this period, leftists of many ethnicities expressed anti-Chinese sentiments in support of Chinese exclusion.Struthers identifies key features that made possible and contributed to a multi-ethnic culture of affinity. Workers from Japan, China, South Asia, the Philippines, and Europe, as well as convicts moved through overlapping migration networks as they built the regional infrastructure of railroads and roads, harbors, and water systems, extracted the resources necessary for such construction and farmed large tracts of consolidated agricultural land. In Los Angeles this regional labor force lived in multi-ethnic neighborhoods where experiences in labor struggles were shared: on streets and in shared public spaces, in bars and pool halls, in ethnic-owned grocery stores and restaurants. Thus, in early twentieth-century Los Angeles, organization of space and residential patterns facilitated interracial and cross-ethnic interaction and exchange. In chapter 2 Struthers delineates anarchists’ spatial and print culture networks. Union halls owned by one organization were shared and used by many organizations. Workers formed reading groups and made use of workers’ libraries. Vacant-lot, free-speech zones, boxcars, and jungle camps were also places where common cause was formed. In Struthers's detailed analysis, individual newspapers that seemed to have a small readership, or that were short-lived, were part of a larger global print culture, amounting to a longer-lived anarchist mass media. Newspapers printed in one language frequently reserved pages for news and advertisements in other languages. Mexican-run newspapers were part of a “trans Mexican network” of Spanish and Italian speakers that extended from the East Coast of North America to the greater Caribbean, the Pacific coast of South America, the Andes, and the Río de la Plata.Struthers revisits the major strikes and labor conflicts that involved Los Angeles radicals. He documents when European immigrant, Mexican, Japanese, and African American men (and occasionally women) came together. In 1903 Japanese and Mexican farm laborers organized the Japanese Mexican Laborers Association and briefly succeeded in extracting concessions during strikes in the sugar beet fields in Oxnard. Struthers asserts that the significance of PLM-led, armed raids into Baja California in 1906, 1908, and 1910–11 against the Porfirian government of Mexico, “rests in the multiracial and transnational composition of the fighting force” (p. 128). Participants included European immigrants from England, Russia, Sweden, Germany, France and Italy, South Asians, Native Americans, and African Americans.The culture of affinity that Struthers emphasizes is not an example of “culture as a whole way of life” as in Raymond Williams's formulation. And Struthers leaves other scholars to explore the possibility of additional evidence of the culture of affinity in Wobblies’ songs or literary and visual expression created by radical leftists. In such sources, as well as the voluminous archive of leftist newspapers that Struthers draws from, it might also be evident that the coalitions leftists created through multi-ethnic affinities were also enabled by the creation of specific conceptions of masculinity. With that said, Struthers's thorough research adds significantly to our understanding of the making of the Los Angeles radical Left.

El Niño Southern Oscillation and enhanced arid land vegetation productivity in NW South America

El Niño Southern Oscillation (ENSO) is a periodic disruption of coupled oceanic-atmospheric conditions in the tropical Pacific, which changes global precipitation regimes. One area strongly affected by positive (el Niño) phases is the Pacific Coast of South America. The specific effects of ENSO on Andean ecological communities have received little attention, however. We examine vegetation gross primary productivity (GPP) on Peru's north coast arid-lands during a recent (2016–2017) el Niño, using a time series of Sentinel 2 imagery. By comparing GPP time-series in three agricultural subregions and three endemic desert vegetation communities, we demonstrate that levels of primary productivity in desert regions during ENSO-positive phases meet or exceed thresholds of adjacent agricultural lands. These results, the first that quantify and spatialize changing GPP between ENSO-neutral and ENSO-positive phases for South American arid-land biomes, both outline the scale and distribution of the el Niño effects on terrestrial ecosystems and highlight the resulting opportunities for human inhabitants. The dramatic changes to endemic vegetation on the normally hyperarid coastal desert of Peru revealed by reconstructed GPP suggest that periodic el Niño precipitation plays a critical role in arid land ecodynamics by enhancing establishment, green growth, and seedbank development. These findings improve our understanding of ENSO's net effects and highlight the roles of abrupt climate events in the arid land ecology of NW South America.

Scale-bearing beauty: Intertidal scale-worms (Polychaeta: Polynoidae) from Punta Blanca (Arequipa, Peru).

Three species of polynoid polychaetes were collected during an exploratory sampling on the rocky shore of Punta Blanca in Arequipa, Peru. Lepidonotus aff. crosslandi peruana Hartmann-Schrder, 1962 differed from the nominal species by the presence of jaws without denticles and bidentate neurochaetae in the third parapodium while Harmothoe aff. hirsuta Johnson, 1897, differed by a disparate distribution of elytral ornamentations. Halosydna parva Kinberg, 1856 is newly recorded for the locality. Comparative tables between Lepidonotus, Halosydna and Harmothoe species recorded for Peru and the Pacific Coast of South America are provided.

Blue mussels of the Mytilus edulis species complex from South America: The application of species delimitation models to DNA sequence variation.

Smooth-shelled blue mussels, Mytilus spp., have a worldwide antitropical distribution and are ecologically and economically important. Mussels of the Mytilus edulis species complex have been the focus of numerous taxonomic and biogeographical studies, in particular in the Northern hemisphere, but the taxonomic classification of mussels from South America remains unclear. The present study analysed 348 mussels from 20 sites in Argentina, Chile, Uruguay and the Falkland Islands on the Atlantic and Pacific coasts of South America. We sequenced two mitochondrial locus, Cytochrome c Oxidase subunit I (625 bp) and 16S rDNA (443 bp), and one nuclear gene, ribosomal 18S rDNA (1770 bp). Mitochondrial and nuclear loci were analysed separately and in combination using maximum likelihood and Bayesian inference methods to identify the combination of the most informative dataset and model. Species delimitation using five different models (GMYC single, bGMYC, PTP, bPTP and BPP) revealed that the Mytilus edulis complex in South America is represented by three species: native M. chilensis, M. edulis, and introduced Northern Hemisphere M. galloprovincialis. However, all models failed to delimit the putative species Mytilus platensis. In contrast, however, broad spatial scale genetic structure in South America using Geneland software to analyse COI sequence variation revealed a group of native mussels (putatively M. platensis) in central Argentina and the Falkland Islands. We discuss the scope of species delimitation methods and the use of nuclear and mitochondrial genetic data to the recognition of species within the Mytilus edulis complex at regional and global scales.

El Niño driven extreme sea levels in an Eastern Pacific tropical river delta: Landward amplification and shift from oceanic to fluvial forcing

As greenhouse warming is predicted to intensify the El Niño–Southern Oscillation (ENSO), it is key to understand relationships between the magnitudes and spatial distribution of ENSO events and associated extreme sea levels (ESLs). Current understanding is lacking for river deltas, where human societies and ecosystems are particularly vulnerable to coastal hazards. Using long-term tide gauge records, we report on ESLs during historical ENSO events of different magnitudes, spatial distribution and temporal evolution in the Guayas delta–Gulf of Guayaquil (Ecuador), the largest estuarine system on the Pacific coast of South America and a relevant hotspot for coastal hazards. Here, we found a landward amplification of sea level anomalies during Eastern Pacific El Niño events, with monthly mean values peaking from +43 cm at the open coast to +75 cm in the inner delta, producing among the highest ENSO driven ESLs ever documented. This landward amplification is shown to coincide with a sea-to-land gradient from a predominantly oceanic (thermosteric) to meteorological (fluvial) El Niño contribution to these ESLs, demonstrating the strong coupling between these two forcings of El Niño. Our findings highlight the strong exposure of coastal societies and ecosystems to ENSO driven ESLs and the pressing need for adaptation measures in face of continued global warming.

Genetic diversity and relatedness inferred from microsatellite loci as a tool for broodstock management of fine flounder Paralichthys adspersus

Paralichthys adspersus is a native species from the Pacific coast of South America that is of great economic importance for Peruvian aquaculture. Even though establishing sustainable farming depends on avoiding irreversible damage to the population gene pool due to processes such as inbreeding, studies focusing on genetically characterizing farmed stocks are yet to be documented. By using ten microsatellite loci on captive and wild individuals of P. adspersus, we successfully characterized the only commercial broodstock of this species in Peru by means of determining the genetic diversity and inferring relatedness. Although most microsatellite loci showed deviations from Hardy-Weinberg equilibrium, the genetic diversity levels in the commercial broodstock were considered healthy compared to those obtained for a wild population, with an average number of alleles of 17.40, an effective number of alleles of 9.14, and an observed and expected heterozygosity of 0.49 and 0.87. No significant differences between the broodstock and the wild population in terms of genetic diversity were observed. The fixation index and analysis of molecular variance also indicated a low rate of differentiation between both populations. In relatedness estimation, the analysis based on five method-of-moment estimators and a maximum-likelihood estimator showed the category “unrelated” as being the most probable relationship among the individuals within the commercial broodstock. Our findings reveal the conservation of genetic diversity in this population and outline potential breeding strategies that hatchery managers could use to minimize the loss of genetic diversity and long-term inbreeding. This could help establish proper genetic management in captive populations of P. adspersus and should apply to other captive stocks where pedigree information is lacking.