Browsing by Author "Landaeta, Mauricio F."
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- ItemDNA reconciles morphology and colouration in the drunk blenny genus Scartichthys (Teleostei: Blenniidae) and provides insights into their evolutionary history(2022) Delrieu-Trottin, Erwan; Hartmann-Salvo, Hans; Saenz-Agudelo, Pablo; Landaeta, Mauricio F.; Perez-Matus, AlejandroThe blenniids of the genus Scartichthys are one of the most common fishes of Central and South American Pacific coastal reefs. This being said, Scartichthys spp. remain difficult to identify in the field, and identification is particularly challenging across the c. 6000 km where three of the four currently accepted species are known to occur in sympatry. A reason for this is that the main taxonomic characters from traditional taxonomy are indeed elusive. In addition, at the same time, species can display multiple colour patterns in the field, depending on their ontogenetic stage, habitat association and reproductive behaviour. Overall, molecular characterization is warranted to help address these issues. In this study, the authors have used a novel approach to revise the genus by combining colouration, morphological and molecular data of representative specimens of the four currently valid species and seven described colour patterns. From this, the authors show that only three of the four species should be considered as valid; Scartichthys gigas (Steindachner, 1876), Scartichthys variolatus (Valenciennes, 1836) and Scartichthys viridis (Valenciennes, 1836), whereas Scartichthys crapulatus (Williams, Smithsonian Contributions to Zoology, 1990, 492, 1-30) should be synonymized with S. viridis. In the same way, the analyses in this study show that one of the colour patterns attributed so far only to S. gigas is characteristic of the juvenile stages of S. viridis. The time-calibrated phylogeny of this study shows that this genus is relatively young and that the estimated time of divergence between S. gigas and S. viridis is c. 1.71 Ma. In comparison, the Desventuradas and Juan Fernandez Islands endemic S. variolatus diverged c. 1.95 Ma. The results of this study help to clarify the taxonomy of Scartichthys.
- ItemEnvironmental DNA reveals temporal variation in mesophotic reefs of the Humboldt upwelling ecosystems of central Chile: Toward a baseline for biodiversity monitoring of unexplored marine habitats(2024) Saenz-Agudelo, Pablo; Ramirez, Paula; Beldade, Ricardo; Campoy, Ana N.; Garmendia, Vladimir; Search, Francesca V.; Fernandez, Miriam; Wieters, Evie A.; Navarrete, Sergio A.; Landaeta, Mauricio F.; Perez-Matus, AlejandroTemperate mesophotic reef ecosystems (TMREs) are among the least known marine habitats. Information on their diversity and ecology is geographically and temporally scarce, especially in highly productive large upwelling ecosystems. Lack of information remains an obstacle to understanding the importance of TMREs as habitats, biodiversity reservoirs and their connections with better-studied shallow reefs. Here, we use environmental DNA (eDNA) from water samples to characterize the community composition of TMREs on the central Chilean coast, generating the first baseline for monitoring the biodiversity of these habitats. We analyzed samples from two depths (30 and 60 m) over four seasons (spring, summer, autumn, and winter) and at two locations approximately 16 km apart. We used a panel of three metabarcodes, two that target all eukaryotes (18S rRNA and mitochondrial COI) and one specifically targeting fishes (16S rRNA). All panels combined encompassed eDNA assigned to 42 phyla, 90 classes, 237 orders, and 402 families. The highest family richness was found for the phyla Arthropoda, Bacillariophyta, and Chordata. Overall, family richness was similar between depths but decreased during summer, a pattern consistent at both locations. Our results indicate that the structure (composition) of the mesophotic communities varied predominantly with seasons. We analyzed further the better-resolved fish assemblage and compared eDNA with other visual methods at the same locations and depths. We recovered eDNA from 19 genera of fish, six of these have also been observed on towed underwater videos, while 13 were unique to eDNA. We discuss the potential drivers of seasonal differences in community composition and richness. Our results suggest that eDNA can provide valuable insights for monitoring TMRE communities but highlight the necessity of completing reference DNA databases available for this region.
- ItemGrowth and condition of larval rockfish in a Patagonian fjord-type inlet : role of hydrographic conditions and food availability(2015) Landaeta, Mauricio F.; Contreras, Jorge E.; Bustos, Claudia A.; Pérez Matus, Alejandro A.
- ItemInterannual variations in the hatching pattern, larval growth and otolith size of a sand-dwelling fish from central Chile(2015) Rodríguez Valentino, Camilo; Landaeta, Mauricio F.; Castillo Hidalgo, Gissella; Bustos, Claudia A.; Plaza, Guido; Ojeda Rossi, Federico Patricio
- ItemMismatch between shape changes, early growth, and condition for a temperate reef fish from an oceanic island(2021) Landaeta, Mauricio F.; Figueroa-Gonzalez, Yanara; Moyano, Gonzalo; Vera-Duarte, Javier; Perez-Matus, Alejandro; Plaza, GuidoSettlement is a key process in the life history of marine fish, when shape and ecological changes occur during the transition from a pelagic larva to a benthic juvenile. We studied the covariation of shape changes, condition, and pre- and post-settlement growth of settlers (17-30 mm) of the wrasse, Pseudolabrus gayi, from the Robinson Crusoe island, south-eastern Pacific. Specimens were collected during late March 2018 from four locations at 20 m depth and from a large, natural intertidal pool. The morphospace and the allometry were characterised by landmarkbased geometric morphometrics, size and growth were estimated using sagittae otolith microstructure analysis, and condition was determined using the Fulton index. The settler's phenotype varied from a robust shape with ventrally oriented mouth opening, to slender specimens with frontally oriented mouth, with similar body morphospace among sites. The mean pelagic larval duration was 44.8 +/- 4.6 days, settling at 19 +/- 2 mm SL. The mean post-settlement growth rate was low (0.09 mm day(-1)), showing low static allometry (3%). Differences among locations occurred in terms of settler's condition and growth prior and after settlement, suggesting effects of the microhabitat and potential predators. Therefore, the variability in the settler's morphospace was decoupled of pre- and post-settlement growth and condition during the transition from pelagic to benthic habitat. Finally, this study highlights the dynamic nature of the settlement-transition period for a temperate reef fish in a period when phenotype variations in body shape and early life-history traits vary asynchronously.
- ItemMorphospace of lanternfish larvae and their interplay with oceanographic conditions from the southeastern Pacific Ocean(2024) Orrego, Fernanda S.; Benitez, Hugo A.; Castillo, Manuel I.; Cumplido, Nicolas; Fabres, Alejandra; Figueroa-Gonzalez, Yanara; Morales, Claudia; Zavala-Munoz, Francisca; Landaeta, Mauricio F.Lanternfish larval morphology is highly variable probably due to their adaptations to highly variable environmental conditions throughout ontogeny. To study the morphological variability of the larval stage of lanternfishes, samples were collected from the southeast Pacific Ocean between 2014 and 2022. Of the 24 species, nine belonged to the subfamily Lampanyctinae, two to the subfamily Diaphinae, one to the subfamily Notolychinae, one to the subfamily Gymnoscopelinae and 11 to the subfamily Myctophinae. A principal component analysis indicated the presence of body shapes varying from a slender and curved body, and upper jaw oriented downwards, with relatively rounded eyes, to taxa with robust bodies, particularly both the head and trunk, and elongated eyes in a dorsal-ventral plane (PC1 33%). Also, specimens varied from having short jaw, short snout, and slender body, to specimens with larger jaw (reaching behind the eye) and taller snout and trunk (PC2, 23%). Allometric effects were related to variations in body curvature and thickness (Diaphus theta, 12.9%), the curvature of the body and position of the eyes (Lampanyctodes hectoris, 25.1%), lengthening of the jaw and increase in eye size (Diogenichthys atlanticus, 24.6%), and a narrower body and smaller eyes (Hygophum bruuni, 20.5%). Four of the five subfamilies showed covariation between morphometrics and environmental conditions. Diaphinae, Gymnoscopelinae and Lampanyctinae body shape covaried with mean sea temperature of the water column, while Myctophinae larval shape covaried with mean salinity. In conclusion, this study quantifies shape variations during early lanternfish ontogeny from the southeastern Pacific Ocean, identifying main differences and allometric changes between the subfamilies belonging to Myctophidae, with a covariation between the shape of most lanternfish larvae and the environmental conditions experienced by myctophid early stages.
- ItemSpatial and temporal variations of coastal fish larvae, ectoparasites and oceanographic conditions off central Chile(2015) Landaeta, Mauricio F.; Zavala Muñoz, Francisca; Palacios Fuentes, Pámela Andrea; Bustos, Claudia A.; Alvarado Niño, Mónica; Letelier, Jaime; Muñoz, Gabriela
- ItemSpatio-temporal patterns of the crustacean demersal fishery discard from the south Humboldt Current System, based on scientific observer program (2014-2019)(2023) Landaeta, Mauricio F.; Hernandez-Santoro, Carola; Search, Francesca, V; Castillo, Manuel, I; Bernal, Claudio; Navarrete, Sergio A.; Wieters, Evie A.; Beldade, Ricardo; Navarro Campoi, Ana; Perez-Matus, AlejandroThis study summarises six years of spatio-temporal patterns of the discarded demersal community fauna recorded by onboard scientific observer program for both artisanal and industrial crustacean fisheries between 2014 and 2019, from mesophotic to aphotic depths (96 to 650 m) along the southern Humboldt Current System (28-38 degrees S). In this period, one cold and two warm climatic events were observed during the austral summer 2014, 2015-2016 (ENSO Godzilla), and 2016-2017 (coastal ENSO), respectively. Satellite information showed that Chlorophyll-a concentration varied seasonally and latitudinally, associated with upwelling centres, while equatorial wind stress decreased southward of 36 degrees S. Discards were composed of 108 species, dominated by finfish and molluscs. The Chilean hake Merluccius gayi was dominant and ubiquitous (occurrence, 95% of 9104 hauls), being the most vulnerable species of the bycatch. Three assemblages were identified: assemblage 1 (similar to 200 m deep), dominated by flounders Hippoglossina macrops and lemon crabs Platymera gaudichaudii, assemblage 2 (similar to 260 m deep), dominated by squat lobsters Pleuroncodes monodon and Cervimunida johni and assemblage 3 (similar to 320 m depth), dominated by grenadiers Coelorinchus aconcagua and cardinalfish Epigonus crassicaudus. These assemblages were segregated by depth, and varied by year, and geographic zone. The latter represented changes in the width of the continental shelf, increasing southward of 36 degrees S. Alpha-diversity indexes (richness, Shannon, Simpson, and Pielou) also varied with depth and latitude, with higher diversity in deeper continental waters (> 300 m), between 2018-2019. Finally, at a spatial scale of tens of kilometres, and a monthly basis, interannual variations of biodiversity occurred in the demersal community. Surface sea temperature, chlorophyll-a, or wind stress did not correlate with discarded demersal fauna diversity of the crustacean fishery operating along central Chile.
- ItemTemperate rocky reef fish community patterns in a coastal marine protected area (MPA) from northern Chile, utilizing remote underwater video cameras (RUVs)(2024) Gres, Mateo; Hune, Mathias; Baldanzi, Simone; Perez-Matus, Alejandro; Landaeta, Mauricio F.Shallow water seascapes are complex systems, important for the life history and connectivity of many marine fish species. Remote Underwater Video cameras (RUVs) are an increasingly used, non-lethal technique able to record the occurrence of reef fish species with little disturbance. In this study, RUVs were installed in a Marine Protected Area (Cha & ntilde;aral Island, northern Chile, 29 degrees 2'S, 71 degrees 34'W) at three different depth strata (5, 10, 15 m) in three different habitats (sand and boulder, bedrock, and kelp forest) during October 2018, July 2021 and October 2021. The RUV system recorded a total of 20 species belonging to 16 families over 73.5 h of videotaping. The most recurrent fishes were damselfish Chromis crusma, Chilean sandperch Pinguipes chilensis, and marblefish Aplodactylus punctatus. There was a significant difference in fish assemblage composition among depth strata and seasons, but not among habitats. In July 2021 (austral winter) higher densities of small cryptobenthic fish (Helcogrammoides spp.) and medium-sized carnivorous Chirodactylus variegatus were detected, whereas P. chilensis was associated to the deeper stratum, and the herbivorous blenny Scartichthys viridis was related to the shallower depths, which is likely due to differences in the habitat structure and composition. Winter 2021 showed a higher species richness than in spring 2018, while the evenness (Pielou's J') was significantly higher in spring 2018 than winter/spring 2021. There was no other strong or consistent pattern, which suggests that most fish species use the entire depth gradient throughout the year. Finally, the results suggest that the use of RUVs for the estimation of biodiversity of rocky reef fishes is a cost-effective way to improve our understanding of nearshore community shifts in relation to environmental forcing.
- ItemVariability in oceanographic conditions affecting Mesophotic Ecosystems along the South Eastern Pacific: Latitudinal trends and potential for climate refugia(2024) de la Maza, Lucas; Wieters, Evie A.; Beldade, Ricardo; Landaeta, Mauricio F.; Perez-Matus, Alejandro; Navarrete, Sergio A.Oceans have been changing at the fastest pace since the beginning of the Holocene. The South Eastern Pacific (SEP), including the Humboldt Upwelling Ecosystem (HUE) is subject to changes in upwelling winds, temperature, El Nin o, and the ever-increasing local anthropogenic stressors, all of which have been documented for surface coastal waters where in-situ and remote observations are readily available. Temporal and spatial changes in the adjacent deeper waters where diverse Mesophotic Ecosystems are found have been scarcely documented. These marine ecosystems have been the focus of ecological studies for less than two decades. Here we provide an overview of the thermal variability at mesophotic depths and assess their potential as climatic refugia along all SEP ecoregions. We analyzed a time series of temperature and salinity from a 19 yr reanalysis based on remote and in-situ observations (CTD, ARGO, XBTs, moorings) to quantify variability in the Tropical (0 -5 degrees S), Northern Warm Temperate (5 -30 degrees S); Southern Warm Temperate (30 -39.5 degrees S) and Magellanic subregions (39.5 -45 degrees S), at two mesophotic depth strata (50 and 100 m), and a reference surface (5 m) depth. We assessed variability in the seasonal, interannual (El Nin o) and 'long-term ' (ca. 20 yr) scales, and the relationship with wind velocities. The thermal depth gradient between surface and mesophotic depths did not change smoothly with latitude but peaked within the northern portion of the warm temperate subregion, decreasing towards lower and higher latitudes. Seasonal variation in temperature was also largest in the north and south temperate subregions and minimal in the Magellanic subregion. Depth dampening of seasonal temperature variation was also strengthened at intermediate latitudes and much reduced in the tropics, where seasonal variation at mesophotic depths was similar to that at the surface. The strong interannual El Nin o events were identified at all depths in tropical and temperate subregions, with stronger standardized effects at mesophotic layers than at the surface. Long-term (ca. two decades) temperature trends were significant and changed direction from warming to cooling along the SEP but were generally patchier at mesophotic layers. Spatial temperature gradients have remained relatively stable over the past two decades and were stronger at the surface than at mesophotic depths, and stronger within the tropics than in all other subregions. Surprisingly, the velocity of climate change was patchier and generally faster at mesophotic layers than at the surface. We conclude that, judging solely by physical environmental conditions, mesophotic ecosystems may be used by species with very different temperature affinities in temperate subregions, while in the tropics, more overlap in temperature affinities of component species may be found. Importantly, while the seasonal amplitude is reduced at mesophotic depth in most subregions, except the tropics, interannual disturbances affect mesophotic depths at least as strongly as they do surface waters and climate change velocities are faster at mesophotic depths than at surface. Thus, these ecosystems are not sheltered from inter-annual and longer-term forcing and their biotas might be more vulnerable to climate change than shallow coastal ecosystems.