UCN-CEAZA
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.
Scallop larvae hatcheries as source of bacteria carrying genes encoding for non-enzymatic phenicol resistance.
Miranda, C., Rojas, R., Geisse, J., Romero, J., & González-Rocha, G.
The main aim of the study was to evaluate the role of scallop hatcheries as source of the floR and cmlA genes. A number of 133 and 121 florfenicol-resistant strains were isolated from scallop larval cultures prior to their transfer to seawater and from effluent samples from 2 commercial hatcheries and identified by 16S rRNA gene sequence analysis, observing a predominance of the Pseudomonas, Pseudoalteromonas and Halomonas genera and exhibiting an important incidence of co-resistance to streptomycin, oxytetracycline and co-trimoxazole. A high percentage of strains from both hatcheries carried the floR gene (68.4% and 89.3% of strains), whereas a lower carriage of the cmlA gene was detected (27.1% and 54.5% of strains). The high prevalence of floR-carrying bacteria in reared scallop larvae and hatchery effluents contributes to enrich the marine resistome in marine environments, prompting the need of a continuous surveillance of these genes in the mariculture environments.
Año: 2015
Palabras claves: Florfenicol; Antimicrobial resistance; floR; Scallop hatchery; Chile.
Referencia APA: Miranda, C., Rojas, R., Geisse, J., Romero, J., & González-Rocha, G. (2015). Scallop larvae hatcheries as source of bacteria carrying genes encoding for non-enzymatic phenicol resistance. Marine Pollution Bulletin, 95(1), 173-182.
Litter and seabirds found across a longitudinal gradient in the South Pacific Ocean.
Miranda-Urbina, D., Thiel, M., & Luna-Jorquera, G.
Abundances and composition of marine litter and seabirds were estimated in the central South Pacific (SP) Ocean between the Chilean continental coast and the Easter Island Ecoregion. Litter was dominated by plastics throughout the study area, but the proportion of plastics was higher at sea and on the oceanic islands than in coastal waters and on continental beaches. Litter densities were higher close to the center of the SP subtropical gyre compared to the continental coast. The seabird assemblage was diverse (28 species), and several endemic species were recorded. Seabird abundances were higher in the coastal waters and around Juan Fernández Islands off the continental coast than in the Oceanic and Polynesian sectors. Endangered species breeding on Salas & Gómez Island were observed in the Polynesian sector, which suggests a high potential for negative interactions between seabirds and floating litter, both occurring in high densities in this sector.
Año: 2015
Palabras claves: Litter; Seabirds; South Pacific Subtropical gyre; Oceanic islands; Motu Motiro Hiva Marine Park.
Referencia APA: Miranda-Urbina, D., Thiel, M., & Luna-Jorquera, G. (2015). Litter and seabirds found across a longitudinal gradient in the South Pacific Ocean. Marine Pollution Bulletin, 96(1-2), 235-244.
Mating rock shrimp hedge their bets: old males take greater risk, but only after careful assessment of the investment scenario.
Ory, N., van Son, T., & Thiel, M.
Mature organisms often have to trade reproductive opportunities against the need to survive, especially in species with exaggerated, sexually selected traits. Life history theory predicts that old males with low residual reproductive value (RRV) would accept greater risk for current reproduction than their younger counterparts. Accordingly, we tested the prediction that, under predation risk, old males of the rock shrimp Rhynchocinetes typus pair with females faster and for a longer time than young males do. We exposed young and old dominant males (in the final ontogenetic stage, called “robustus”) to a female in the absence and presence of a predator. As predicted, older robustus males modified their mating behavior when exposed to a predator. However, in contrast to the prediction, they delayed female seizure under predation risk, possibly to carefully assess the actual threat before initiating female guarding. Once they had established the mate-guarding position, old robustus males did not interrupt it until the end of female spawning and, in the presence of predators, even guarded the female significantly longer than in predator-free treatments. In contrast, younger robustus males did not delay female seizure but abandoned the female repeatedly when a predator was present, suggesting that they perceived and responded to the predation risk. Our results suggest that older robustus males have the experience to assess threats before engaging in risky behaviors that bolster their reproductive success. Although consistent with the theory that low RRV individuals should accept greater reproductive risk, we suggest that old individuals do not recklessly engage in risky behaviors but rather cautiously evaluate the threats before investing in a potentially terminal reproductive event.
Año: 2015
Palabras claves: AgeMate-guarding, Mating behavior,Predation risk,Residual reproductive value,Risk-taking strategies.
Referencia APA: Ory, N., van Son, T., & Thiel, M. (2015). Mating rock shrimp hedge their bets: old males take greater risk, but only after careful assessment of the investment scenario. Behavioral Ecology And Sociobiology, 69(12), 1975-1984.
Numbers and sizes of the shrimp Rhynchocinetes uritaiKubo, 1942 (Decapoda: Caridea) caught in bait and refuge traps.
Osawa, Y., Bauer, R., Aoki, M., & Thiel, M.
Catch rates and sizes of hingebeak shrimp Rhynchocinetes uritaiKubo, 1942 were studied with two types of traps: bait traps that were exposed for 1-2 days and unbaited “refuge traps” exposed for 2-4 weeks. Shrimp were collected twice a month from June 2010 to May 2012 on rocky substrata in Oura Bay, Shimoda, Japan. Overall the numbers of shrimp caught did not differ between the two trap types, but when adjusted for soak times, the bait traps had substantially higher catch rates than the refuge traps. Addition of light to the bait traps had no significant effect on catch rates. However, shrimp in the baited traps were significantly larger than those in the refuge traps. The results show that size distribution can be greatly affected by trap type. Consequently, using two types of traps simultaneously increases not only the catch efficiency but also ensures that all sizes of the reproductively mature shrimp population are sampled in adequate numbers, which is especially important in protandric hermaphrodites.
Año: 2015
Palabras claves: Hingebeak shrimp; bait traps; catch efficiency; refuge traps.
Referencia APA: Osawa, Y., Bauer, R., Aoki, M., & Thiel, M. (2015). Numbers and sizes of the shrimp Rhynchocinetes uritai Kubo, 1942 (Decapoda: Caridea) caught in bait and refuge traps. Journal Of Crustacean Biology, 35(6), 768-775
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