El Quisco Research Articles

Size overlap in intertidal decapod communities on a central Chilean rocky beach (El Quisco, 32°24′S, Valparaiso region, Chile)

Abstract The intertidal crustaceans on the Chilean coast are characterized by high diversity and niche specialization. The present study applied a size-overlap null model analysis for intertidal decapod communities in a central Chilean rocky beach (El Quisco, 32°24′S). The application of six models simulations revealed that there is a size overlap, confirmed by the results of all those six simulations. This means that the reported species would share their ecological niches. The results agree with the first classical ecological descriptions for Chilean intertidal decapods at a local scale and support the observations for similar species on the southern Pacific and southern Atlantic coasts, and the results of the null model agree with a first comparative study of decapods in the north and on the central Chilean rocky coast.

Design as a Driver for Multidisciplinary Teams: An Applied Research Case in El Quisco, Chile

The evolution of research and industry has increased the indeterminacy of problems and their multidimensionality. Simultaneously, the teams facing these problems are now multidisciplinary, and there has been a rising struggle to identify and establish a route that results in innovation. The role of design in this operation has been shown to be crucial, as it defines methods that enable a common frame for researchers from multiple backgrounds, making the development of the project easier and richer. CAPCA Software allows public workers to access real-time information from their territory, allowing for better and on-time decisions aiming for sustainable resource expenditure. Designers in the team conducted a process that connected the diverse team with users, creating a general formulation of the project and then translating this to an interface, demonstrating the importance of the role of design in the methodological approach to these new dynamic problems and digital innovation.

Impact of Population Growth in the Central Coastal Zone of Chile: Factors for Estimating Tourism Carrying Capacity Based on the Case Study of One Latin American Seaside Resort

El Quisco is a district and popular seaside resort on the coast of Chile that has suffered the effects of the growing demand for second homes and tourism activities. The district has the fourth highest influx of a floating population in the region, which has had numerous impacts on the district at several levels. The objective of this article is to examine the issue of carrying capacity in Chile and its public management at the local level. To this end, this research developed an exploratory and instrumental case study. Carrying capacity problems were first identified in the existing literature. This information was subsequently complemented with more local information by means of: analysis of territorial planning instruments (TPIs) relating to the district; participative workshops with municipal government stakeholders; and, lastly, confirmation of the problems identified through correlation analysis of available historical data. The main result of this research was the determination of carrying capacity issues in El Quisco. This broadly coincides with indications from the existing literature and TPIs, while factors identified by local stakeholders are territory-specific, giving rise to new measurement variables. It was possible, in turn, to rule out certain carrying capacity issues perceived by the community.

Lunar influences in the diet habits and selectivity of larval clingfish Gobiesox marmoratus.

The influence of the lunar cycle on the feeding habits, feeding success and selectivity was tested in situ on larval stages of the clingfish Gobiesox marmoratus (Gobiesocidae). Gobiesox marmoratus larvae and their prey were collected in the water column during the lunar cycle in austral spring 2015 and 2016, in shallow waters (<30 m depth) of El Quisco, central Chile. Feeding incidence was high (80-100%) throughout the moon cycle. The diet was composed of 32 prey items, being gastropod larvae and invertebrate eggs the most important. Prey composition varied among lunar phases with the lowest prey richness during new moon. During 2016, G. marmoratus larvae ingested the lowest number, but the largest prey during new moon. In spring 2015, there were no significant changes in the abundance of each prey taxon in the water column among moon phases, but in spring 2016 there were significant differences in the abundance of cypris and copepod nauplii, particularly between full and new moon. Feeding selectivity index showed that gastropod larvae were positively selected throughout the lunar cycle during spring 2015. In spring 2016, invertebrate eggs were selectively ingested in full moon and third quarter, but at a new moon G. marmoratus larvae selected gastropod larvae. Mean temperature of the water column and its vertical gradient and nocturnal cloud cover influences the feeding success of larval G. marmoratus. Lunar illumination favoured only an increase of richness of prey items. Therefore, nocturnal cloud cover precludes a greater influence of lunar illumination in the larval trophic ecology of this crypto-benthic fish.

The influence of regional and local oceanography in early stages of marine fishes from temperate rocky reefs

Nearshore ichthyoplankton assemblages are constantly influenced by the dynamics of coastal environments (i.e. daily thermal gradients and coastal currents), as well as by regional environmental forcing, such as upwelling events. The aims of this study were to describe larval and postlarval fish assemblages on a short-time scale and relate their intra- and interannual fluctuations to local (< 1 km) and regional (~ 40 km) oceanographic conditions, at two locations of central Chile (Montemar and El Quisco), 50 km distant from each other. Environmentally, spring–summer 2015–2016 was more stable than spring–summer 2016–2017, evidencing weaker temperature fluctuations. In addition, the first season of the study showed positive temperature anomalies that agree with the warm phase of El Nino–Southern Oscillation (ENSO) 2015. Both larval abundance (29,090 ind. 100 m−3 period 1; 23,100 ind 100 m−3 period 2) and postlarval CPUE (6.8 ind. light trap−1 night−1 period 1; 4.8 ind. light trap−1 night−1 period 2) decreased in the second period of study. The structure of the larval assemblages was significantly related to seawater temperature and wind regime, and showed seasonal fluctuations in the abundance, with higher densities in spring, and lower in summer, while postlarval assemblages did not relate significantly to any physical variable. At the interannual scale, the stability of the water column probably promotes fish reproduction, allowing higher larval abundances, while an environmentally unstable year could alter reproductive processes. Local topography influences environmental conditions: El Quisco is more exposed to regional upwelling, and showed higher abundances, species richness, and a predominance of benthic species. Abrupt weekly fluctuations in ichthyoplankton composition and abundance point out that fish larvae can quickly respond to short-term environmental variations.

Parasitic copepods affect morphospace and diet of larvae of a temperate reef fish.

The effects of ectoparasites on larvae of the clingfish Gobiesox marmoratus were evaluated at the dietary and morphometric levels. The larvae and ectoparasites were collected by nearshore plankton samplings during October, November and December 2013 off El Quisco Bay, central Chile. The standardized abundance of total larvae and those ectoparasitized larvae (PL) was positively related and high parasite prevalence was found throughout the sampling period (up to 38%). Geometric morphometrics analyses indicate main changes in the shape through early ontogeny and subtle but significant variations between PL and non-parasitized larvae (NPL). Prey composition varied between PL and NPL; small size (<6 mm standard length, LS ) parasitized larval G. marmoratus ate mostly gastropod larvae, whereas small non-parasitized specimens ate mainly cirripede nauplii. All larger (>8 mm LS ), pre-settlement stages parasitized by Trifur and, or Caligus copepods had content in their gut, suggesting that ectoparasites did not diminish prey capture in host with larger size. Morphometric and dietary changes occurring during larval development were decoupled, both for PL and NPL. The maintenance of a slender, more hydrodynamic body through pelagic development and the ingestion of less-mobile prey in PL suggests non-lethal effects of ectoparasitism on rocky-reef fish larvae.

Oceanographic and lunar forcing affects nearshore larval fish assemblages from temperate rocky reefs

ABSTRACTThe influence of oceanographic features and moon phases on ichthyoplankton assemblages in a temperate nearshore rocky reef off El Quisco Bay, central Chile, was assessed during austral spring–summer 2015–2016 using Bongo nets. Wind direction was predominantly south-west, and ocean temperature increased gradually during the study period, fluctuating between 11.6°C and 17.7°C. A relatively cold period (from late September to early December, 12.42 ± 0.64°C) was distinguished from a relatively warmer phase (from mid-December to February, 13.56 ± 1.08°C). Nearshore ichthyoplankton was composed of 13,700 individuals, belonging to 43 taxa. Larval Strangomera bentincki (Clupeidae) were collected in high numbers between late September and late October with peaks during full moon and first quarter (maximum = 734 ind. 100 m−3); larval Engraulis ringens (Engraulidae) was most abundant between late October and late December 2015, with peaks during the third quarter and full moon. Principal Component Analysis of ichthyoplankton data explained more than 44% of total variance and showed the influence of cold/warm periods in the structuring of larval fish assemblages. Water temperature had more influence than lunar phase in the structure and composition of nearshore fish larvae off central Chile. We conclude that larval fish assemblages found in nearshore waters change on a seasonal scale by differences in the reproductive activity among species, and that lunar phase exerts a low, but significant effect on the abundance of fish larvae, but this variability is species-specific.

Geochemical characterization of two distinctive systems with evidence of chemosynthetic activity, explored at the SE Pacific margin off Chile (46°S and 33°S)

This study presents the geochemical composition of superficial sediment under oxic and suboxic bottom water conditions along the Chilean continental margin (SE Pacific), where evidence for benthic chemosynthetic activity associated with diffuse seeping of chemically reduced fluids has been reported. The exploration was carried out at: (1) the Chilean Triple Junction (CTJ), at a water depth of ∼2900m, with the additional indication of hydrothermal activity near a methane-rich cold-seep area (46°S) (German et al., 2010); and (2) the El Quisco methane seep site (EQSS), at ∼340mwater depth (33°S) (Melo et al., 2007; Krylova et al., 2014). While the deeper CTJ is located within an oxic environment (dissolved oxygen in the bottom waters: 164μM), the shallower EQSS lies within a suboxic environment (dissolved oxygen in bottom water: 23μM), located within the lower limit of the SE Pacific oxygen minimum zone (OMZ).Pore water from short cores was analyzed for dissolved major, minor, and trace elements (Cl, Na, Mg, K, Ca, Sr, Si, B, P, Ba, Pb, Mn, Fe, Cd, U, and Mo), δ13DIC, sulfide, sulfate, and methane. The solid sediment fraction was likewise analyzed for total organic carbon (TOC), metals, and redox potential. Elevated sediment temperatures were found in superficial sediments (5–13°C) at the CTJ site, which could be due to warm fluids associated with the proximity of the ridge, where hydrothermal vents may occur. Reduced fluids were also present here, indicated by higher Mn fluxes toward the water column even in oxidized sediments (RPD>8cm), which contrasted with the lower fluxes in reduced sediments of the EQSS site (RPD∼2cm). 13C-depleted DIC, anomalously low pore water Cl (∼15ppb), and low concentrations of other major elements may be the result of dilution by fluid seeping and precipitation of major elements, producing authigenic enrichment (Ca, Mg, Sr). The fluid could also: (a) be diluted by pure water produced during methane hydrate dissociation, as observed in other cold-seep areas; and (b) correspond to clay mineral dehydration, as reported in plate subduction systems. The reducing conditions established at the CTJ conduct the Cd enrichment at a similar magnitude of that seen at the shallower suboxic site (EQSS). Evidence of chimney or vent fauna was not observed. At the EQSS, higher TOC and total sulfide contents were consistent with enhanced deposition of organic matter and reducing conditions developed in the OMZ, favoring the authigenic enrichment of Cd, U and Pb. The geochemical evidence, based only on methane concentrations and δ13DIC, is insufficient to establish the presence of methane seeps, as previously reported.

Interannual variations in the hatching pattern, larval growth and otolith size of a sand-dwelling fish from central Chile

The interannual variation (2010–2013) of larval abundance, growth and hatching patterns of the Chilean sand stargazer Sindoscopus australis (Pisces: Dactyloscopidae) was investigated through otolith microstructure analysis from samples collected nearshore (<500 m from shore) during austral late winter-early spring off El Quisco bay, central Chile. In the studied period, the abundance of larval stages in the plankton samples varied from 2.2 to 259.3 ind. 1000 m−3; larval abundance was similar between 2010 and 2011, and between 2012 and 2013, but increased significantly from 2011 to 2012. The estimated growth rates increased twice, from 0.09 to 0.21 mm day−1, between 2011 and 2013. Additionally, otolith size (radius, perimeter and area), related to body length of larvae, significantly decreased from 2010 to 2012, but increases significantly in 2013. Although the mean values of microincrement widths of sagitta otoliths were similar between 2010 and 2011 (around 0.6–0.7 μm), the interindividual variability increases in 2011 and 2013, suggesting large environmental variability experienced by larvae during these years. Finally, the hatching pattern of S. australis changed significantly from semi-lunar to lunar cycle after 2012.

Impacto de la demanda de un turismo social en la sustentabilidad de la actividad en el balneario de El Quisco, Provincia de San Antonio - Chile

Every summer Chile’s Central Coast undergoes the effects of social tourism, as a vast number of low-income visitors arrive from Chile’s most densely populated areas in the Central Zone.Despite congestion and saturation of available touristic resources, the number of visitors increases every year, contravening classic touristic demand models that define migration to less congested resources as the outcome of congestion.This analysis will be focused on El Quisco beach, located at Valparaiso’s Region, a touristic destination that clearly represents this process of mass tourism socialization.The goal of this research is to understand the demand composition that social tourism generates, by determining its nature and identifying the factors that define its behavior. These factors are related to the visitor’s origin, displacement, permanence, loyalty, social bonds, gender, income, consumption capacity, and to the degree of satisfaction regarding touristic supplies such as beaches, equipment, and infrastructure.Understanding this demand behavior it is key to develop policies enabling the planning of sustainable social tourism, and allowing for low-income families to access high-quality resources.

Austrogena: a new genus of chemosymbiotic bivalves (Bivalvia; Vesicomyidae; Pliocardiinae) from the oxygen minimum zone off central Chile described through morphological and molecular analyses

A new genus, Austrogena, is established for a new species of vesicomyid bivalve (A. nerudai sp. nov.) described from sediments within the oxygen minimum zone off El Quisco, Chilean margin (∼33°S) from ∼340 m depth. The new genus is distinguished by a unique combination of conchological and anatomical features for vesicomyids, including the presence of an escutcheon, a lunular incision, an elongated 4-b tooth in the left valve, a subumbonal pit, both inner and outer pairs of demibranchs and the absence of pallial sinus and processes on the inner vulva of the inhalant siphon. In comparison with the majority of highly specialized pliocardiins, the alimentary gut of Austrogena is not straight and its middle gut changes direction twice. Molecular analysis, based on COI sequences, confirms that A. nerudai sp. nov. is not related to any other pliocardiin. So far, Austrogena gen. nov. is the only endemic vesicomyid genus in the south-eastern Pacific area and A. nerudai sp. nov. is the fourth species of vesicomyids reported from chemosynthetic communities of the Chilean margin. The description of the new genus further contributes to knowledge of biodiversity of chemosymbiotic assemblages in the south-eastern Pacific.http://zoobank.org/urn:lsid:zoobank.org:pub:476A9734-B510-4954-A623-2C0E1F254F9A.

Larval fish assemblages in nearshore coastal waters off central Chile: temporal and spatial patterns

In this study we identified spatial and temporal patterns in the distribution and abundance of larval stages of several fish species in nearshore waters off central Chile. Larvae were sampled monthly at two close (20 km apart) but contrasting localities, El Quisco and Las Cruces. Surveys corresponded to standard plankton tows stratified according to bathymetry and distance from shore. Our results indicate that at both localities: (1) there is a seasonal reproductive pattern for most of the species studied; (2) there is a seasonal-related change in larval species composition and abundance, with austral Winter–Spring being the time of greatest diversity; (3) larval stages of several species that, as adults occupy intertidal, estuarine–riverine, subtidal, benthic-demersal, epipelagic or mesopelagic habitats, are found within these coastal environments; (4) there is a distinctive cross-shelf pattern of larval distribution, which seems to correspond, at least for the intertidal species, with the shallower (<30 m depth) portion of area surveyed; and (5) there is a coupling between the patterns of distribution and abundance of the entire ichthyoplankton assemblage with short-term physical features such as wind forcing, Ekman transport, and local currents. Our findings suggest that both the specific composition as well as the abundance of larval fish species varies spatially and temporally and that this variability may result from the interaction of physical and biological factors at different scales.

Alongshore and temporal variability in chlorophyll a concentration in Chilean nearshore waters

Phytoplankton and particulate organic matter constitute the primary food source for adult filter-feeders, as well as for larval stages of many benthic and pelagic organisms. The structure and dynamics of nearshore benthic communities may be associated with variation in nearshore primary production. However, we know little about the scales of variability in phytoplankton in nearshore waters along open coasts, or about their causes. To characterize spatial and temporal patterns of chl a concentration, we conducted 2.5 yr of daily, shore-based monitoring at 3 sites separated by 10s of km within an upwelling region in central Chile. We found that: (1) peaks in chl a concentration were typ- ically short-lived, persisting no longer than 4 d, (2) blooms occurred in spring to early summer months at all sites, but also during autumn months at 1 site (Las Cruces), and (3) the intensity and frequency of blooms were consistently different among sites; highest concentrations were at Las Cruces, lower at El Quisco, and the lowest at Quintay. Analyses of wind data and surface temperature, and inspection of Advanced Very High Resolution Radiometer (AVHRR) satellite images, suggested that among-site dif- ferences were due, at least in part, to alongshore variation in upwelling intensity and the formation of warm-water pockets or upwelling shadows in sections of the coast, such as Las Cruces. In contrast to the spatial pattern described offshore and over larger spatial scales, chl a concentrations were signifi- cantly lower at the coldest site, Quintay, located at the core of an upwelling center (Pta. Curaumilla), than at the warmer site of Las Cruces, which lies downstream from upwelling. Day-to-day variation in chl a levels during spring at Las Cruces seems related to the alongshore intrusion of waters upwelled upstream. Overall, the pattern observed at our 3 sites, together with previous studies at other up- welling systems, suggests that sections of the coast around 15 to 20 km downstream (equatorward) from upwelling centers could exhibit consistently higher phytoplankton concentrations than sites lo- cated in front of upwelling centers, generating a source-sink type of geographic pattern of nearshore nutrients and phytoplankton along the coast.

Avoiding offshore transport of competent larvae during upwelling events: The case of the gastropod Concholepas concholepas in Central Chile

The coast of central Chile is characterized by the occurrence of coastal upwelling during the austral spring and summer seasons, which probably has important consequences for the cross‐shelf transport of larval stages of many species. Three cruises were conducted off the locality of El Quisco during upwelling‐favorable wind periods to determine the surface distribution of epineustonic competent larvae of the gastropod Concholepas concholepas during such events. Contrary to the predictions of a traditional model, where neustonic‐type larvae are transported offshore under such conditions, competent larvae of this species were exclusively found in the area between the shore and the upwelling front. Two additional cruises were conducted during calm periods to determine diel variation in the vertical distribution of C. concholepas competent larvae. The absence of competent larvae at the surface during early night hours suggests a reverse vertical migration. Thus, the retention of C. concholepas competent larvae in the upwelled waters could be the result of the interaction between their reverse diel vertical migration and the typical two‐layer upwelling dynamics.

Temporal and spatial variation in settlement of the gastropod Concholepas concholepas in natural and artificial substrata

Settlement of Concholepas concholepas (Gastropoda: Muricidae) on natural and artificial substrata was studied between April 1999 and March 2001 at two sites in central Chile; the Las Cruces Marine Reserve and El Quisco Management and Exploited Area. Four different artificial materials were tested in the low intertidal zone during 1999 settlement season to determine their properties as settlement and microhabitat substrata for competent Concholepas larvae. Globular pads made of plastic filaments were identified as the best artificial collectors, exhibiting overall higher settlement rates than rock plots and lower variability among replicates within a given site. Thus, subsequent monitoring of settlement used only these globular pads that were replaced twice monthly. The temporal pattern of settlement was remarkably similar from year to year, starting at the end of austral winter (August–September) and ending in summer (December–January), defining a temporally restricted settlement season. Settlement at two sites within the Marine Reserve of Las Cruces was significantly higher than at sites in El Quisco. However, during the second settlement season, an additional site at El Quisco exhibited settlement rates comparable to those observed at Las Cruces. The results show that Concholepas settlement varies significantly over scales of several hundreds of metres as well as tens of kilometres, probably due to differences in coastal oceanographic conditions.