UCN-CEAZA
Genetic diversity in Chilean populations of rainbow trout, Oncorhynchus mykiss.
Carcamo, C., Diaz, N., & Winkler, F.
The rainbow trout Oncorhynchus mykiss, was first introduced in Chile between 1905 and 1920 and is currently widely distributed in Chile from Antofagasta (23°S) to Patagonia (55ºS). The broad range of the geographic and climatic distributions of this species in Chile offers a unique opportunity to study the effect of naturalization of an introduced species on its genetic variability. It is of particular importance to observe the genetic variability of populations in the northern range of this species distribution, in a transition zone where a Mediterranean-type climate changes to an arid climate. The present study analyzed allozymic variability and distribution within and between populations of O. mykiss from the river basins of Elqui and Limarí rivers, and six culture strains, using starch-gel protein electrophoresis. Populations were found to be in Hardy-Weinberg equilibrium and the average values of He (0.045), polymorphism (13.9%) and allele per locus (1.19) are similar to rainbow trout in its native distributional range. About 77.8% of the genetic variability was within population, similar to the variability reported for wild populations in the northern hemisphere. However, a marked genetic differentiation between wild populations was also found. This is likely to be the consequence of initial founder effects followed by subsequent introgression of resident populations caused by reseeding with trout of different origins in both basins.
Año: 2015
Palabras claves: Oncorhynchus mykiss, rainbow trout, Salmonidae, genetic variation, aquaculture, conservation.
Referencia APA: Carcamo, C., Diaz, N., & Winkler, F. (2015). Genetic diversity in Chilean populations of rainbow trout, Oncorhynchus mykiss. Latin American Journal Of Aquatic Research, 43(1), 59-70.
Management of marine resources through a local governance perspective: Re-implementation of traditions for marine resource recovery on Easter Island.
Aburto, J., Gaymer, C., Haoa, S., & González, L.
Easter Island (Rapa Nui) is one of the most isolated places in the world. The local Rapanui people have noticed an extreme decline in marine resources, which is due to the exploitation of these resources. Top-down regulations (e.g. fisherman and boat registrations and restrictions on catch-length and fishing season and location) implemented by the central fishery authorities located ∼4000 km from the island do not represent the cultural heritage and interests of the Rapanui people. According to the local people, one of the traditional ways to protect marine resources was the taboo (or tapu in Rapa Nui) that regulated the fish harvest. Key informants were interviewed to assess what they knew about the tapu in fisheries and so that the feasibility of its implementation could be assessed based on current local conditions. The tapu that had the greatest potential impact on regulating open water resources, especially tuna, was the traditional belief that consumption of open-water fish during winter months would cause asthma. According to the interviewees, the real reason for this tapu was to protect the fish during its reproductive period, and the asthma threat was only a way to enforce the restriction. At present, tapu is not respected because of the high economic activity related to the tourism that demands fish like tuna all year. Even though many Rapanui people agree that tapu re-implementation would be the best alternative to recover marine resources, people also think it is difficult to implement under modern conditions. We propose to promote a participatory process for development of a local governance structure that will use local traditions and beliefs, including tapu, to support the local decision-making process for reverting the decline of marine resources.
Año: 2015
Palabras claves: Easter Island; Resource management; TEK; Taboo; Local governance.
Referencia APA: Aburto, J., Gaymer, C., Haoa, S., & González, L. (2015). Management of marine resources through a local governance perspective: Re-implementation of traditions for marine resource recovery on Easter Island. Ocean & Coastal Management, 116, 108-115.
Characterization and pathogenicity of Vibrio splendidus strains associated with massive mortalities of commercial hatchery-reared larvae of scallop Argopecten purpuratus (Lamarck, 1819)
Rojas, R., Miranda, C., Opazo, R., & Romero, J.
Three strains (VPAP16, VPAP18 and VPAP23 strains) were isolated as the most predominant organisms from 3 different episodes of massive mortalities of larval cultures of the Chilean scallop Argopecten purpuratus occurred in different commercial hatcheries located in northern Chile. The main aims of this study were to identify the pathogenic strains and investigate their pathogenic activity. Based on selected phenotypic features and sequence identity of the 16S rRNA gene and the housekeeping gene, RNA polymerase α-chain rpoA, all pathogenic strains were identified as Vibrio splendidus. Healthy 10–day–old scallop larvae cultures exhibited mortality percentages of 69.61 ± 3.35%, 79.78 ± 6.11% and 61.73 ± 3.71% after 48 h when were inoculated with 1 × 106 CFU (colony forming units) mL−1 of VPAP16, VPAP18 and VPAP23 strains, respectively, and evidenced that concentrations ⩾104 CFU mL−1 would probably be detrimental for the larval culture. The main clinical signs observed in challenged larvae for 24 h were bacterial swarms on the margins of the larvae, extension and disruption of the velum, detachment of velum cilia cells and digestive tissue necrosis. Otherwise, challenge assays using pathogenic strains stained with 5-([4,6-dichlorotriazin-2-yl]amino)fluorescein hydrochloride (5-DTAF) evidenced that after 1 h stained bacteria were detected in high density in the digestive gland and the margin of the shell. When larval cultures were inoculated with cell-free extracellular products (ECP) of V. splendidus strains, exhibited larval mortalities higher than 70% (VPAP16), 80% (VPAP18) and 50% (VPAP23) after 24 h, even when ECP were treated with proteinase K or heat, indicating that extracellular pathogenic activity is mainly mediated by non-proteic thermostable compounds. In this study all Koch’s postulates were fulfilled and it was demonstrated for the first time the pathogenic activity of V. splendidus strains on reared-larvae of scallop A. purpuratus and prompt the necessity to maintain this species at concentrations lower than 104 CFU mL−1 to avoid episodes of mass mortalities in scallop hatcheries.
Año: 2015
Palabras claves: Bacteria; Vibrio splendidus; Scallop larvae; Vibriosis; Shellfish pathology; Argopecten purpuratus.
Referencia APA: Rojas, R., Miranda, C., Opazo, R., & Romero, J. (2015). Characterization and pathogenicity of Vibrio splendidus strains associated with massive mortalities of commercial hatchery-reared larvae of scallop Argopecten purpuratus (Lamarck, 1819). Journal Of Invertebrate Pathology, 124, 61-69.
First Records of Striped Boarfish Evistias acutirostris and Ornate Butterflyfish Chaetodon ornatissimus from Easter Island 1.
Hernández, S., García, M., Gaymer, C., & Friedlander;, A.
Here we report on two new reef fish species from the remote and isolated Easter Island—the striped boarfish Evistias acutirostris and the ornate butterflyfish Chaetodon ornatissimus were observed during scuba dives and underwater video around Easter Island, as well as at nearby Apolo Seamount. These observations are the first records of these species for the southeastern Pacific, which represents a major extension to their distributions and raises questions about the origins and persistence of reef fishes in remote subtropical locations.
Año: 2015
Palabras claves:
Referencia APA: Hernández, S., García, M., Gaymer, C., & Friedlander, A. (2015). First Records of Striped Boarfish Evistias acutirostris and Ornate Butterflyfish Chaetodon ornatissimus from Easter Island1. Pacific Science, 69(4), 525-529.
Analysis of Life-History Traits in a Sex-Changing Marine Shrimp (Decapoda: Caridea: Rhynchocinetidae).
Osawa, Y., Aoki, M., Thiel, M., & Bauer, R.
The hypothesis of protandrous (male to female) sex change was tested for the first time in a rhynchocinetid shrimp, Rhynchocinetes uritai, with an analysis of life-history traits. Samples were taken monthly for 2 years in Oura Bay, Japan, using a combination of bait and refuge traps. Breeding was seasonal but extended from spring through autumn, with female-phase individuals (FPs) producing broods successively, with their ovaries maturing for a new spawn during incubation of a previous brood. Females incubated numerous (∼500–4000) embryos that suffered insignificant mortality before hatching. Recruitment of juveniles after planktonic larval development began in summer and peaked during the autumn, with negligible recruitment during winter and spring. Cohort analysis confirmed the hypothesis of protandric sex change in this species, with juveniles maturing into the male phase (MP) during their first reproductive season at an age of 6–10 mon, depending on the time of recruitment. Sex change occurred during the following winter when transitional individuals matured into FPs during their second reproductive season at an age of ≥18 mon. Two cohorts were followed from recruitment until the end of the study, indicating a life span of 21–25 mon. Aside from its sexual system, this sex-changing species showed no obvious differences in reproductive and other life-history traits from those of gonochoric species from similar latitudes and habitats.
Año: 2015
Palabras claves:
Referencia APA: Osawa, Y., Aoki, M., Thiel, M., & Bauer, R. (2015). Analysis of Life-History Traits in a Sex-Changing Marine Shrimp (Decapoda: Caridea: Rhynchocinetidae). The Biological Bulletin, 228(2), 125-136.
Predation of Juvenile Jasus frontalis : An Endemic Spiny Lobster of the Juan Fernández Archipelago, Chile.
Petit, I., Gaymer, C., Palma, Á., & Wahle, R.
This study identified and quantified in the field the natural predators of juvenile spiny lobster Jasus frontalis, an endemic, ecologically relevant species, and the most valuable local commercial catch of Robinson Crusoe Island. It also assessed the predation pressure that these predators exerted on juveniles lobsters and whether they showed preferences for particular body sizes within the juvenile size range. A series of tethering experiments were performed in three coastal sites of Robinson Crusoe Island (Juan Fernández archipelago. Chile). In overnight experiments, survival of juveniles decreased over time in all three sites, reaching ∼50% at the end of the experiment. The evidence suggests that fish were relevant predators since mortality of lobsters was proportional to their abundance. Although video surveillances depicted numerous octopus attacks, their abundance did not exhibit a statistically significant relationship with lobster mortality. Predatory events were not selective of juvenile sizes. These results are fundamental to understand one of the key factor (i.e., predation) that affects the juvenile (and more vulnerable) benthic phase of J. frontalis.
Año: 2015
Palabras claves: Predation, oceanic island, juveniles, lobsters, Jasus frontalis.
Referencia APA: Petit, I., Gaymer, C., Palma, Á., & Wahle, R. (2015). Predation of Juvenile Jasus frontalis: An Endemic Spiny Lobster of the Juan Fernández Archipelago, Chile. Journal Of Shellfish Research, 34(3), 1085-1089.
Species separation within the Lessonianigrescens complex (Phaeophyceae, Laminariales) is mirrored by ecophysiological traits.
Koch, K, Thiel, M., Tellier, F., Hagen, W., Graeve, M., Tala, F., Laeseke, P., and Bischof K.
Lessonia nigrescens used to be an abundant kelp species along the Chilean coast, but recent molecular studies revealed the existence of a L. nigrescens species complex, which includes the two cryptic species Lessonia berteroana and Lessonia spicata. Since these species have different distributions (16°S–30°S for L. berteroana and 29°S–42°S for L. spicata), they experience differences in environmental conditions, such as solar irradiance, seawater temperature and air exposure during low tide. This study tested to what extent the genetic distinctness of each of the two species [identified by a mitochondrial marker (atp8/trnS)] is reflected by ecophysiological traits (total lipids, fatty acid composition, phlorotannins, pigments and variable chlorophyll a fluorescence of PSII) in response to the respective environmental conditions, prevailing along the latitudinal gradient. We studied algal individuals from eight populations (27°S–32°S, including the species overlapping zone). Phlorotannins, pigments and Chl a fluorescence of PSII were most crucial for species-specific adaptations at the respective growth sites, whereas changes in total lipids and fatty acid compositions were negligible. Hence, species differentiation within the L. nigrescens complex is also manifested at the ecophysiological level. These findings may help to predict kelp responses towards future environmental changes.
Año: 2015
Palabras claves: Chile; fatty acid composition; Lessonia nigrescens complex; phlorotannins; photosynthetic pigments.
Referencia APA: Koch, K, Thiel, M., Tellier, F., Hagen, W., Graeve, M., Tala, F., Laeseke, P., and Bischof K. (2015). Species separation within the Lessonia nigrescens complex (Phaeophyceae, Laminariales) is mirrored by ecophysiological traits. Botanica Marina 2015; 58(2): 81–92.
Transcriptome characterization of the ascidian Pyura chilensis using 454-pyrosequencing data from two distant localities on the southeast Pacific.
Haye, P. & Gallardo-Escárate, C.
This study describes the results from transcriptomes sequenced by 454-pyrosequencing from two populations separated by 10° of latitude of the endemic tunicate Pyura chilensis. Most transcripts were assembled in 43,972 contigs with an average length of 842 nucleotides. De novo assembly revealed that less than 30% of the contigs were annotated to Gene Ontology terms. A total of 71,662 single nucleotide polymorphisms (SNPs) were detected in 14,712 contigs. In silico differential expression of contigs annotated for SNPs revealed several genes differentially expressed in individuals collected from both populations. The present genomic resource will provide the basis to perform functional genomics on the species via the localization of genomic markers that can aid in determining levels of local adaptation, overall genetic structure and the genetic assessment of restocking programs for this species.
Año: 2015
Palabras claves: RNA-Seq; SNP; Pyura chilensis; Tunicates; Transcriptome; Pyrosequencing.
Referencia APA: Haye, P. & Gallardo-Escárate, C. (2015). Transcriptome characterization of the ascidian Pyura chilensis using 454-pyrosequencing data from two distant localities on the southeast Pacific. Marine Genomics, 20, 19-22.
High variability of levels of Aliivibrio and lactic acid bacteria in the intestinal microbiota of farmed Atlantic salmon Salmo salar L.
Godoy, F., Miranda, C., Wittwer, G., Aranda, C., & Calderón, R.
In the present study, the structure of the intestinal microbiota of Atlantic salmon (Salmo salar L.) was studied using culture and culture-independent methods. Three adult specimens of S. salar were collected from a commercial salmon farm in Chile, and their intestinal microbiota were studied by partial sequencing of the 16S rRNA gene of pure cultures as well as of clone libraries. Out of the 74 bacterial isolates, Pseudomonas was the most predominant genus among cultured microbiota. In clone libraries, 325 clones were obtained from three adult fish, and a total of 36 operational taxonomic units (OTUs) were identified. This indicated that lactic acid bacteria (Weissella, Leuconostoc, and Lactococcus genera) comprised more than 50 % of identified clones in two fishes. This was in contrast with the high dominance of a single OTU (99 sequences) of Aliivibrio sp. related to the pathogenic Aliivibrio salmonicida species and the absence of lactic acid bacteria in the third fish, suggesting a condition of an asymptomatic non-healthy carrier. It is clear that molecular identification of 16S rRNA gene libraries obtained from intestinal content samples is effective in determining the overall structure of the intestinal microbiota of farmed Atlantic salmon enabling detection of a minority of taxa not previously reported as part of the intestinal microbiota of salmonids, including the genera Hydrogenophilus, Propionibacterium, Cronobacter, Enhydrobacter, Veillonella, Prevotella, and Atopostipes, as well as to evaluate the health status of farmed fish when evaluating the dominance of potential pathogenic species and the incidence of lactic acid bacteria.
Año: 2015
Palabras claves: Aquaculture, Intestinal microbiota, Aliivibrio, Salmon farming, Salmo salar.
Referencia APA: Godoy, F., Miranda, C., Wittwer, G., Aranda, C., & Calderón, R. (2015). High variability of levels of Aliivibrio and lactic acid bacteria in the intestinal microbiota of farmed Atlantic salmon Salmo salar L. Ann Microbiol, 65(4), 2343-2353
On the advantage of sharing a holdfast: effects of density and occurrence of kin aggregation in the kelp Lessonia berteroana.
Segovia, N., Vásquez, J., Faugeron, S., & Haye, P.
We investigated the density-dependent and genetic relatedness that regulate the occurrence of inter-individual (genet) fusion forming plurigenotypic organisms in the brown alga Lessonia berteroana. Recruitment generally occurs at high densities in the inter-tidal, allowing contact of neighbouring holdfasts as they grow and expand on the substrate. Algal density, by contrast, is regulated by the effects of herbivory and wave impact, which often lead to low holdfast density. Herein, we investigated whether the occurrence of plurigenotypic organisms and their genotypic composition (number of genotypes per plurigenotypic organism) are density dependent and affected by kin selection in the inter-tidal kelp L. berteroana. Four microsatellite loci were used to analyse DNA from 260 samples obtained from shared and non-shared holdfasts, at two sites with high and two site with low holdfast density. Analyses showed that fusions forming plurigenotypic organisms are extremely common. Interestingly, the frequency of fusions was higher in low-density sites, in which 100% of the plants had at least two genotypes and the average was 3.5. In high-density sites, 62% of plants were plurigenotypic, with an average of 2.8 genotypes per plant. Additionally, we found that genotypes that shared a holdfast had a significantly higher genetic relatedness than the average in the population, compatible with a kin structure. Density dependence and kin structure suggest that the occurrence of plurigenotypic organisms is linked to environmental quality, and that kin or multilevel selection may be favouring the fusion of genetically related genets.
Año: 2014
Palabras claves: Density dependence; fusion of individuals; genetic relatedness; kelp; kin aggregation; kin selection; microsatellites.
Referencia APA: Segovia, N., Vásquez, J., Faugeron, S., & Haye, P. (2015). On the advantage of sharing a holdfast: effects of density and occurrence of kin aggregation in the kelp Lessonia berteroana. Mar Ecol, 36(4), 1107-1117
Growth Inhibition of Bacterial Fish Pathogens and Quorum-Sensing Blocking by Bacteria Recovered from Chilean Salmonid Farms.
Fuente, M., Miranda, C., Jopia, P., González-Rocha, G., Guiliani, N., Sossa, K., & Urrutia, H.
The main goal of this study was to find bacterial isolates with the ability to inhibit the growth of the fish pathogens Aeromonas hydrophila, Vibrio anguillarum, and Flavobacterium psychrophilum and to inhibit the blockage of the quorum-sensing (QS) system. A total of 80 gram-negative strains isolated from various freshwater Chilean salmonid farms were studied. We determined that 10 strains belonging to the genus Pseudomonas inhibited at least one of the assayed fish pathogens. Of these, nine strains were able to produce siderophores and two strains were able to inhibit the growth of all assayed pathogenic species. When the 80 strains were examined for QS-blocking activity, only the strains Pseudomonas sp. FF16 and Raoultella planticola R5B1 were identified as QS blockers. When the QS-blocker strains were analyzed for their ability to produce homoserine lactone (HSL) molecules, thin-layer chromatography analysis showed that both strains were able to produce C6-HSL– and C8-HSL–type molecules. Strain R5B1 did not show growth inhibition properties, but strain FF16 also led to inhibition of growth in A. hydrophila and F. psychrophilum as well as to siderophore production. Pseudomonas sp. FF16 exhibited potentially useful antagonistic properties and could be a probiotic candidate for the salmon farming industry.
Año: 2015
Palabras claves:
Referencia APA: Fuente, M., Miranda, C., Jopia, P., González-Rocha, G., Guiliani, N., Sossa, K., & Urrutia, H. (2015). Growth Inhibition of Bacterial Fish Pathogens and Quorum-Sensing Blocking by Bacteria Recovered from Chilean Salmonid Farms. Journal Of Aquatic Animal Health, 27(2), 112-122.
Citizen scientists and marine research: volunteer participants, their contributions, and projection for the future.
Thiel, M., Penna-Díaz, M. A., Luna-Jorquera, G., Salas, S., Sellanes, J., & Stotz, W.
Año: 2014
Palabras claves:
Referencia APA: Thiel, M., Penna-Díaz, M. A., Luna-Jorquera, G., Salas, S., Sellanes, J., & Stotz, W. (2014). Citizen scientists and marine research: volunteer participants, their contributions, and projection for the future. Oceanography and Marine Biology: An Annual Review, 52, 257-314. DOI: 10.1201/b17143-6