Browsing by Author "Garmendia, Vladimir"

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    Environmental 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, Alejandro
    Temperate 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.
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    Observations on the early development of the kelpfish Myxodes viridis (Clinidae) with the first description of their spawning habitat in subtidal kelp forests (Lessonia trabeculata)
    (2021) Ruz, Catalina S.; Garmendia, Vladimir; Munoz-Cordovez, Rodrigo; Wieters, Evie; Perez-Matus, Alejandro
    The spawning sites, embryonic development, and initial larval stages were described for the Chilean kelpfish, Myxodes viridis. Six different egg clutches were found attached by an elastic filament to the fronds of the subtidal kelp, Lessonia trabeculata, at shallow depths (0-7 m). All egg clutches were cared for by one large (>15 cm TL) male, and egg color varied depending on the developmental stage. Embryonic development until hatching was categorized into 7 stages, which were completed within about 18 days in the laboratory. Recently hatched larvae presented fully pigmented eyes, a well-developed mouth with major shape changes in the head during the first week suggesting their ability to feed on plankton early in their larval development.
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    The Hidden Diversity of Temperate Mesophotic Ecosystems from Central Chile (Southeastern Pacific Ocean) Assessed through Towed Underwater Videos
    (2023) Campoy, Ana Navarro; Perez-Matus, Alejandro; Wieters, Evie A.; Alarcon-Ireland, Rodrigo; Garmendia, Vladimir; Beldade, Ricardo; Navarrete, Sergio A.; Fernandez, Miriam
    The largely unexplored diversity in temperate mesophotic ecosystems (TME, similar to 30-150 m depth) has attracted much attention over the past years. However, the number of studies and knowledge of TME diversity and ecology remains limited and geographically restricted. The absence of information on how assemblages vary across environmental gradients and with depth for most regions also limits our capacity to delimit conservation areas and devise management plans effectively. This study focuses on TME from central Chile and describes the depth distribution of reef fishes and benthic invertebrates and algae for the first time. Through the analysis of towed underwater video surveys between 4.7-95.5 m in multiple sites, we show that total reef fish density and richness decrease with depth but increase with local topographic complexity. The depth-related density varies among fish species and trophic groups, and it reverses in the case of Sebastes oculatus, which increases in density with depth. Sponges and gorgonians dominate benthic assemblages below 20 m depth, and brachiopods and anemones increase below 40 and 60 m, respectively. Some of these species form animal forests which, to some extent, replace the shallow-water kelp forests as structural habitat providers. Nevertheless, the reef fish and benthic community do not show a clear structure with depth or across studied sites. We highlight the urgency to intensify and expand the quantitative characterization of these communities, through this and other methodologies, to better define ecological patterns and advance towards conservation plans for TME, including the Souteastern Pacific region.
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    The use of fishers' knowledge to assess benthic resource abundance across management regimes in Chilean artisanal fisheries
    (2021) Garmendia, Vladimir; Subida, Maria Dulce; Aguilar, Ainara; Fernandez, Miriam
    Globally, marine fisheries remain largely unassessed, particularly small-scale fisheries in developing countries. Fishers' knowledge has proven to be valuable to help fill gaps of information in otherwise unassessed fisheries. This study tested the reliability of fishers' knowledge to estimate the abundance of two benthic resources, locos (Concholepas concholepas) and keyhole limpets (Fissurella spp.), across two management regimes, territorial user rights for fisheries (TURF) and open access areas (OAA), over similar to 500 km of coastline in central Chile. Fishers' knowledge (FK) was quantified using systematic interviews and compared to direct assessments (DA). Additionally, resource abundance was compared between the fishing regimes, considering regions with different concentration of TURFs (and consequently different availability of OAAs). The results show that abundances estimated by the two methods were highly consistent for the most valuable resource (the loco) and quite reliable for the keyhole limpet (for 67% of the comparisons). Abundances of both resources were higher in TURFs than in OAAs, a pattern detected by both FK and DA. The results clearly show the potential of this approach to be applied for the Chilean benthic fisheries over large scales. Interestingly, the results also show significantly lower abundance of locos in OAAs than in TURFs at coves immersed in zones with low availability of open access fishing grounds, suggesting the influence of effort displacement after the implementation of TURFs. This ancillary result highlights the need for seascape management plans that consider the potential, unintended effects of TURFs on resources beyond their boundaries. These findings are of both local and global interest, supporting the use of FK to inform management in unassessed small-scale fisheries.