Gonzalo Gajardo

Gonzalo Gajardo
Universidad de Los Lagos · Biological Sciences and Biodiversity

31.12
 · 
PhD
About
91
Research items
10,789
Reads
1,536
Citations
Research Experience
Mar 1987 - Dec 2014
Laboratorio de Genética, Acuicultura & Biodiversity. Universidad de Los Lagos, Osorno
Position
  • Laboratory Head
Mar 1986
Universidad de Los Lagos
Position
  • Laboratory Head
Description
  • The brine shrimp Artemia as a model extremophile for studying adaptation and speciation, and as a live diet for Larviculture (www.laboratoriogenetica.cl). Impact of exotic and naturalized salmonids on native biodiversity (www.biodiversity.cl).
Mar 1986
Universidad de Los Lagos
Position
  • Professor (Full)
Description
  • https://www.google.cl/search?urceid=navclient&hl=es&ie=UTF-8&rlz=1T4PCTC_esCL376CL376&q=frontiers+Gonzalo+Gajardo
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Projects
Projects (3)
Project
Illuminate the colonization and establishment of non-native salmonids in South America through ecological and genetics approaches
Project
This project funded by the regional government (GORE X region) is based on Chiloé island, southern Chile, and seeks to monitor a marine ecosystem (interior sea) heavily impacted by salmon and mussel farming. One of the problems found by the mussel industry and low-scale artisan farmers, is lack of seed settlement, which is critical for the activity. By monitoring environmental variables and two critical set of genes, one related to immune competence and other specifically related to settlement in mussels and "picoroco" (Austromegabalanus psittacus), we expect to relate ecosystem permeability to larval connectivity (landscape genetics approach).
Project
Laguna de la Sal es un sitio no registrado por la literatura para el microcrustáceo Artemia, un extremófilo que tolera hasta 10 veces la salinidad del agua de mar producto de adaptaciones sorprendentes. Por tal motivo es el único animal habitante en lagos y lagunas hipersalinas, costeras o interiores, que se encuentran principalmente en zonas tropicales y sub-trópicales. De ahí que llama la atención encontrar un sitio con Artemia a 53° latitud sur, el más austral de Chile.
Research
Research items (91)
Article
Full-text available
Different pathways of propagation and dispersal of non-native species into new environments may have contrasting demographic and genetic impacts on established populations. Repeated introductions of rainbow trout (Oncorhynchus mykiss) to Chile in South America, initially through stocking and later through aquaculture escapes, provide a unique setti...
Article
Full-text available
Laguna de los Cisnes (53°15’S) is a remote and unusual salty lagoon located in the Chilean Patagonia, declared natural monument to protect bird diversity in the area, which could also serve as a natural laboratory to monitor climate change. This study reports basic water, sediment and plankton characteristics observed during a summer (December) sam...
Project - Laguna de la Sal en Porvenir, Tierra del Fuego (53°17’00’’ S; 70°23’38’’ W), el laboratorio natural más austral de Chile con el extremófilo Artemia (Crustacea).
Update
project title in English: Lagoon of salt in Porvenir, Fireland (Tierra del Fuego), the most austral natural laboratory containing the brine shrimp Artemia.
Article
Full-text available
The populations of Artemia (or brine shrimp) from the Americas exhibit a wide variation in the amount of interphase heterochromatin. There is interest in understanding how this variation affects different parameters, from the cellular to the organismal levels. This should help to clarify the ability of this organism to tolerate brine habitats regul...
Article
Full-text available
Previous researches have established that the swim speed of some microcrustaceans is influenced by chemical compounds emitted by conspecifics. We examined the hypothesis that cuticular compounds present on the body surface of A. franciscana, the most widespread member of Artemia genus, play a role in the swim speed of conspecific males. The movemen...
Project - Laguna de la Sal en Porvenir, Tierra del Fuego (53°17’00’’ S; 70°23’38’’ W), el laboratorio natural más austral de Chile con el extremófilo Artemia (Crustacea).
Update
The brine shrimp Artemia is a micro-crustacean, well adapted to the harsh conditions that severely hypersaline environments impose on survival and reproduction. Adaptation to these conditions has taken place at different functional levels, from the individual (molecular-cellular-physiological) to the population level. Such conditions are experienced by very few equivalent macro-planktonic organisms; thus, Artemia can be considered a model animal extremophile offering a unique suite of adaptations. While Artemia sites are mainly in tropical and sub-tropical regions, it is quite interesting to find Artemia in the Patagonian region of southern Chile. Laguna de la Sal ("Salty lagoon) is to our knolwedge the southernmost location with Artemia (53° Latitude South), thus we consider this place a natural laboratory to study the dynamic of the Artemia population and its particular suit of adaptations under unique environmental conditions in a context of climate change.
Article
The palm ruff, Seriolella violacea (Cojinoba), is a potential new species for Chilean aquaculture. To approach Cojinoba larviculture, an experimental Artemia enrichment emulsion, containing docosahexaenoic acid (DHA)/eicosapentaenoic acid (EPA) = 2.5, supplemented with vitamin E, astaxanthin, and β-glucan, was evaluated in both Artemia and Cojinoba...
Article
Full-text available
Two behavioral experiments were performed to test that A. franciscana shows specific courtship patterns, which in part, would be governed by semiochemicals released by females. The courtship ethogram, based on 30 adult virgin pairs (1 female v/s 1 male) individually video recorded for 1 hour, revealed that males display four independent activity pa...
Article
Full-text available
Knowledge about the genetic underpinnings of invasions-a theme addressed by invasion genetics as a discipline-is still scarce amid well documented ecological impacts of non-native species on ecosystems of Patagonia in South America. One of the most invasive species in Patagonia's freshwater systems and elsewhere is rainbow trout (Oncorhynchus mykis...
Article
Full-text available
AimThe ecological effects of biological invasions are well documented, but little is known about the effects of invaders on the genetic structure of native species. We examined the phylogeography, genetic variation and population structuring of two galaxiid fishes, Aplochiton zebra and A. taeniatus, threatened by non-native salmonids, and whose con...
Article
Full-text available
The brine shrimp Artemia (Crustacea) and a diversity of halophilic microorganisms coexist in natural brines, salterns and laboratory cultures; part of such environmental microbial diversity is represented in the gut of Artemia individuals. Bacterial diversity in these environments was assessed by 16S rRNA gene denaturing gradient gel electrophoresi...
Data
Table S3. Results of bayescan and lositan programs for outlier detection in (a) brown trout and (b) rainbow trout.
Data
Table S4. (a) Differentiation of brown trout populations expressed as (a) pairwise FST comparisons (below diagonal) and Dest (above diagonal) among Chilean and Falklands populations and (b) as pairwise FST estimated from neutral (below diagonal) and gene-linked (above diagonal) markers.
Data
Table S5. Correlations between PST, FST, PST/FST and geographical distance.
Data
Table S2. Summary genetic statistics for brown trout considering (a) global sample (over all populations) and (b) population-specific.
Data
Full-text available
Figure S2. Relationship between observed (solid line) and neutral (dashed line) PST/FST, for four phenotypic traits of (a) brown trout and (b) rainbow trout.
Data
Figure S1. Individual growth curves, represented as cumulative scale growth profiles (mm) at each growth circulus, among invasive brown trout (n: 5) and rainbow trout (n: 7) populations.
Data
Table S1. Strains of rainbow trout and brown trout introduced in Chile and the Falkland Islands.
Article
Full-text available
Invasion success may be expected to increase with residence time (i.e., time since first introduction) and secondary releases (i.e., those that follow the original introduction), but this has rarely been tested in natural fish populations. We compared genetic and phenotypic divergence in rainbow trout and brown trout in Chile and the Falkland Islan...
Article
Full-text available
Biological invasions create complex eco-logical and societal issues worldwide. Most of the knowledge about invasions comes only from success-ful invaders, but less is known about which processes determine the differential success of invasions. In this review, we develop a framework to identify the main dimensions driving the success and failure of...
Article
Full-text available
The relationship between invaders and the pathogens encountered in their new environment can have a large effect on invasion success. Invaders can become free from their natural pathogens and reallocate costly immune resources to growth and reproduction, thereby increasing invasion success. Release from enemies and relaxation of selective pressures...
Article
Full-text available
The ability of invasive species to adapt to novel conditions depends on population size and environmental mismatch, but also on genetic variation. Away from their native range, invasive species confronted with novel selective pressures may display different levels of neutral versus functional genetic variation. However, the majority of invasion stu...
Conference Paper
Biological invasions represent one of the greatest threats to aquatic ecosystems, particularly in locations a high degree of isolation and endemism, such as southern South America. In this region, salmonids are top-level invaders, but information about their dispersal, persistence, and population dynamics is still limited. Here, we used available h...
Article
Full-text available
The brine shrimp Artemia is a micro-crustacean, well adapted to the harsh conditions that severely hypersaline environments impose on survival and reproduction. Adaptation to these conditions has taken place at different functional levels or domains, from the individual (molecular-cellular-physiological) to the population level. Such conditions are...
Article
1. Direct ecological effects of biological invasions have been widely documented, but indirect genetic effects on native species are poorly known. In many cases, this is because of the lack of information on the genetic structure of species affected by invasions. 2. We used microsatellite DNA loci to estimate the genetic structure and gene flow pat...
Article
Full-text available
The conservation of data deficient species is often hampered by inaccurate species delimitation. The galaxiid fishes Aplochiton zebra and Aplochiton taeniatus are endemic to Patagonia (and for A. zebra the Falkland Islands), where they are threatened by invasive salmonids. Conservation of Aplochiton is complicated because species identification is...
Data
Hybrid assignments based on (a) simulated membership proportions of 100 multilocus genotypes per class using HYBRIDLAB and (b) results of admixture analysis using STRUCTURE: A. zebra parentals, A. taeniatus parentals, F1 hybrids, F2 hybrids and backcrosses. Results from the admixture analysis in STRUCTURE are for K = 2, averaged from 20 runs. Each...
Data
Nucleotide sequence alignment of mitochondrial DNA of Aplochiton zebra (A) and Aplochiton taeniatus (B) according to (a) COI haplogroups and (b) Cyt b haplogroups. (DOC)
Data
Microsatellite allele frequencies per locus per species (Aze1-Aze4). (DOC)
Conference Paper
Aplochiton zebra and Aplochiton taeniatus are two galaxiid fishes endemic to Patagonia and, in the case of Aplochiton zebra, also present in the Falklands Islands where they are threatened by salmonid invasions. Identification of Aplochiton is complicated because the two species are ecologically and morphologically very similar and include resident...
Article
Full-text available
Aquaculture is a major source of invasive aquatic species, despite the fact that cultured organisms often have low genetic diversity and tend to be maladapted to survive in the wild. Yet, to what extent aquaculture escapees become established by means of high propagule pressure and multiple origins is not clear. We analysed the genetic diversity of...
Article
Mate choice significantly impacts upon population divergence and therefore speciation, recognition of equals being critical in cases where species and divergent populations coexist. The New World species of the brine shrimp Artemia, A. franciscana and A. persimilis, were compared through Scanning Electron Microscopy (SEM) for the following traits:...
Article
Full-text available
Exotic salmonids were deliberately introduced to the Southern Hemisphere during the last part of the 20th century, initially to boost sport fishing and later to develop an aquaculture industry. Early introductions were justified by governments on purely utilitarian arguments as it was felt that translocated salmonids would capitalize on otherwise '...
Article
Full-text available
The Chilean saline lakes are distributed mainly in the Atacama desert in northern Chile and the southern Patagonian plains. The scarce studies are restricted mainly to northern Chilean saline lakes, and these revealed that the main component in these ecosystems are the halophylic copepod Boeckella poopoensis Marsh 1906, or the brine shrimp Artemia...
Article
Rainbow trout Oncorhynchus mykiss and brown trout Salmo trutta are the world’s two most widespread exotic fishes, dominate the fish communities of most cold- temperate waters in the southern hemisphere and are implicated in the decline and extirpation of native fish species. Here, we provide the first direct comparison of the impacts of rainbow and...
Article
Full-text available
Rhizobacteria are capable of stimulating plant growth through a variety of mechanisms that include improvement of plant nutrition, production and regulation of phytohormones, and suppression of disease causing organisms. While considerable research has demonstrated their potential utility, the successful application of plant growth promoting rhizob...
Article
Zooplankton diversity in shallow salt lakes of the Andean countries in South America is low and distribution is highly dependent on salinity, which varies from moderate to high. At salinities lower than 90 g/l, the halophilic copepod Boeckella poopoensis (Marsh, 1906) predominates, whereas above that level the anostracan Anemia franciscana (Kellogg...
Article
The brine shrimp Artemia (Crustacea, Branchiopoda), a paradigmatic inhabitant of hypersaline lakes, has molecular features to survive under stressful conditions, such as the p26 heat shock protein. We report the RFLP fingerprinting pattern (four restriction enzymes) of a 217 bp fragment of exon2 of the Hsp26 gene in six Artemia franciscana and four...
Article
Full-text available
Chromosomal rearrangements have played a key role in the speciation of the New World sexual Artemia species (Crustacea, Anostraca) A. franciscana and A. persimilis. The species differ by a chromosome duplication (2n+2=44 in A. persimilis vs 2n=42 in A. franciscana), and a greater amount of heterochromatin (HCH) in A. franciscana. To investigate thi...
Article
The brine shrimp Artemia is a well known animal extremophile adapted to survive in very harsh hypersaline environments. We compared the small stress proteins artemin and p26, and the chaperone hsc70 in encysted embryos (cysts) of the New World species, A. franciscana and A. persimilis. Cysts of the former, from San Francisco Bay, USA (SFB), were us...
Article
Full-text available
La celebración este año del bicentenario del natalicio de Darwin y de los 150 años de la publicación de su libro El origen de las especies es el preámbulo conceptual para dos eventos que ocurrirán con ocasión del bicentenario de la independencia nacional: el año de la biodiversidad y el congreso de la Asociación Latinoamericana de Genética, ALAG 20...
Article
Full-text available
We used an invaded stream fish community in southern Chile to experimentally test whether the diversity of exotic species affects their competitive impact on a native species. In artificial enclosures an established invasive, rainbow trout, Oncorhynchus mykiss, and a potential invader, Atlantic salmon, Salmo salar, reduced the growth rate of native...
Article
An allozyme survey was conducted in three naturalized populations of rainbow trout, Oncorhynchus mykiss (Walbaum), from rivers in two Andean lakes of southern Chile. The analysis was based on 32 presumed loci, 10 of which were variable, and revealed that the mean percentage of polymorphic loci (P= 21.8%; range = 15.6-28.1%), the mean number of alle...
Article
Full-text available
Biodiversity can be measured at different hierarchical levels, from genetic diversity within species to diversity of ecosystems, though policy-makers tend to use species richness. The 2010 goal of reducing biodiversity loss, agreed by the subscribers to the Convention on Biological Diversity, requires simple and reliable protocols to evaluate biodi...
Article
Full-text available
A preliminary biometric and ecologic database for the brine shrimp Artemia from Mexico and Chile is presented. The area abounds in small and seasonal ponds and large inland lakes, the latter mainly located in Mexico, although relatively large and isolated lakes are found in complex hydrological settings in pre-high plateau areas of Chile. This pape...
Article
Aim Two species of the brine shrimp, namely Artemia franciscana Kellogg and A. persimilis Piccinelli and Prosdocimi, inhabit Chile. Most studies so far have shown that A. franciscana is the most widely distributed species in Chile, with A. persimilis present only in Chilean Patagonia. In general, there is good agreement between morphological and ge...
Article
The impact of supplementing lipid emulsions rich in eicosapentaenoic acid (EmEPA), docosahexaenoic acid (EmDHA) or saturated fatty acids (EmCOCO) to a standard algal diet [3:1 mixture of Isochrysis galbana (T-iso) and Chaetoceros neogracile, St-diet] on Argopecten purpuratus broodstock was evaluated. Broodstock fecundity was compared as well as the...
Article
Larvae of the Chilean-Peruvian scallop Argopecten purpuratus were fed a Dunaliella tertiolecta diet (Dun-diet) supplemented with lipid emulsions, rich in 20:5n-3 (EmEPA), 22:6n-3 (EmDHA) or in saturated fatty acids (EmCOCO). A mixed algal diet of Isochrysis galbana (T-iso) and Chaetoceros neogracile served as a positive control (St-diet). Lipid sup...
Article
Hatchery-reared Argopecten purpuratus larvae were fed a Dunaliella tertiolecta-diet (DUN-diet) supplemented with 0%, 20% or 40% of a highly unsaturated fatty acid (HUFA) lipid emulsion (ICES Reference Emulsions), rich in docosahexaenoic acid (22:6n−3, DHA) and eicosapentaenoic acid (20:5n−3, EPA). A standard diet (ST-diet), consisting of a mixture...
Article
The impact of dietary fatty acids on the fatty acid composition and content in different organs (digestive gland, adductor muscle and male and female gonad) of Argopecten purpuratus was evaluated during the process of gonad maturation under controlled laboratory conditions. A mixed algal diet of Isochrysis galbana (clone T-Iso), Pavlova lutheri, Ch...
Article
The Chilean-Peruvian scallop, Argopecten purpuratus, is the southernmost representative of the genus and has become an aquaculture commodity in Chile as a result of 20 y of culture practice promotion after natural beds were almost exhausted by overexploitation. Chromosome preparations of A. purpuratus D-larvae from three samples, two from commercia...
Article
The endemic marine gastropod Chorus giganteus represents a significant part of the benthic biomass subject to heavy exploitation by artisanal fisheries in Chile. Overexploitation has restricted its formerly wide distribution to few sites, and this study deals with the electrophoretic characterisation of three populations from the two main fishing g...
Chapter
The brine shrimp Artemia comprises a group of bisexual and parthenogenetic, morphologically similar, species very likely to have diverged from an ancestral form living in the Mediterranean area some 5.5 million years ago (Abreu-Grobois and Beardmore, 1982; Abreu-Grobois, 1987; Badaracco et al. 1987), though this estimate, based on allozymes, could...
Article
Chromocentres, i.e. heavily stainable heterochromatic areas with highly repetitive DNA (a 130-bp repeat in the order of 6 x 105 copies per haploid genome) observed in the resting nucleus, are a reliable taxonomic trait and a good marker for speciation in Artemia. This chromosome marker was evaluated in populations of two New World sibling species:...
Article
Full-text available
During the fifties Brncic and the Dobzhansky's school, using the fruit fly Drosophila as a test organism, introduced the term integration of the genotype. or genetic coadaptation, which has had great impact on thinking in today's evolutionary biology. In this work we use the brine shrimp Artemia - in many respects a sort of aquatic Drosophila as a...
Article
The brine shrimp Artemia, a typical inhabitant of hypersaline environments and characterized by a highly subdivided population structure, was used as a model to evaluate, under standardized laboratory conditions (at 65 ppt), primary reproductive traits (offspring quality and quantity) along with levels of reproductive isolation and degrees of diver...
Article
Dietary supplementation with lipid emulsions during broodstock conditioning of Argopecten purpuratus was used to manipulate the fatty acid composition of the eggs. The scallops were fed a mixed algal diet either alone (Al) or supplemented with an emulsion rich in ethyl esters of docosahexaenoic acid (DHA; Al+EmDHA) or eicosapentaenoic acid (EPA; Al...