UCN-CEAZA
Genetic assessment of parentage in the caridean rock shrimp Rhynchocinetes typus based on microsatellite markers.
Bailie, D., Thiel, M., Fitzpatrick, S., Connolly, M., Prodöhl, P., & Hynes, R.
Over the past decade, the common rock shrimp, Rhynchocinetes typus H. Milne Edwards, 1837, has been the focus of extensive investigations on mating behaviour. The species is now perceived as a model system for the study of reproductive strategies and sexual conflict in crustaceans displaying external fertilization. Using molecular markers, the current study assesses whether social mating behaviour in common rock shrimp translates into true genetic parentage. In a large mesocosm tank with >200 individuals of both sexes, the analysis of 15 families (22 eggs per female) for three informative microsatellites unambiguously confirmed multiple paternity in 11 instances (73%) involving, in each case, two to four males. Where more than one male was identified siring a particular brood, reproductive skew was apparent towards a single individual. Results suggest that multiple paternity in this species results from subordinate male coercive behaviour, female solicitation of multiple male matings or a combination of both.
Over the past decade, the common rock shrimp, Rhynchocinetes typus H. Milne Edwards, 1837, has been the focus of extensive investigations on mating behaviour. The species is now perceived as a model system for the study of reproductive strategies and sexual conflict in crustaceans displaying external fertilization. Using molecular markers, the current study assesses whether social mating behaviour in common rock shrimp translates into true genetic parentage. In a large mesocosm tank with >200 individuals of both sexes, the analysis of 15 families (22 eggs per female) for three informative microsatellites unambiguously confirmed multiple paternity in 11 instances (73%) involving, in each case, two to four males. Where more than one male was identified siring a particular brood, reproductive skew was apparent towards a single individual. Results suggest that multiple paternity in this species results from subordinate male coercive behaviour, female solicitation of multiple male matings or a combination of both.
Año: 2014
Palabras claves: Cryptic female choice; multiple paternity; convenience polyandry.
Referencia APA: Bailie, D., Thiel, M., Fitzpatrick, S., Connolly, M., Prodöhl, P., & Hynes, R. (2014). Genetic assessment of parentage in the caridean rock shrimp Rhynchocinetes typus based on microsatellite markers. Journal Of Crustacean Biology, 34(5), 658-662.
Efectos economicos de la estrategia de cosechas multiples en el cultivo del ostion del norte Argopecten purpuratus:una oportunidad para mejorar la competitividad.
Perez, E.
Una situación recurrente en el mercado de muchas especies bajo cultivo acuícola es la tendencia en la disminución del precio internacional en oposición al aumento en los costos de los insumos, lo que obliga a la industria a ser innovadora al momento de rentabilizar la inversión. Una opción poco explorada es el aumento del valor de la producción a través de una cuidadosa selección de tamaños y tiempos de cosechas. Las cosechas parciales permiten que calibres subóptimos puedan tener el tiempo necesario de crecimiento hasta alcanzar mejores atributos, al mismo tiempo que la fracción de mejor crecimiento es cosechada y puesta disponible en el mercado. Difiere significativamente de la estrategia alternativa de cosechas totales, donde la totalidad de la producción es cosechada al mismo tiempo. Así, el óptimo económico será resultado del tiempo de primera cosecha (DPC), de la longitud de cosecha (LC), número de cosechas (NC) e intervalo de tiempo (∆t) entre cosechas sucesivas. Mediante un modelo de simulación, alimentado con valores reales de una empresa de cultivo de ostión del norte (Argopecten purpuratus) se analizó el resultado económico de la estrategia de cosechas múltiples. Los resultados indican que las combinaciones alternativas de DPC, LC, ∆t y NC generan distintos niveles de rendimientos económicos, aspecto que debiera ser considerado por los productores. En los escenarios simulados de cosechas, una decisión incorrecta en este sentido podría generar una diferencia del orden de US$ 510.000.
Año: 2014
Palabras claves: Argopecten purpuratus, ostión del norte, cosechas múltiples, rendimiento económico,acuicultura.
Referencia APA: Perez, E. (2014). Efectos economicos de la estrategia de cosechas multiples en el cultivo del ostion del norte Argopecten purpuratus: una oportunidad para mejorar la competitividad. Latin American Journal Of Aquatic Research, 42(1), 180-191
Monitoring the sustainability of Lessonia nigrescens (Laminariales, Phaeophyceae) in northern Chile under strong harvest pressure.
Vega, J., Broitman, B., & Vásquez, J.
In the last decade, exploitation of Lessonia nigrescens in northern Chile has been carried out using the best practices agreed upon by consensus between fishermen, industry, government, and scientists. These practices focus on the selective harvest of sporophytes to allow the maintenance of a reproductive stock, facilitating recruitment and minimizing grazing of benthic herbivores. To improve coverage and accessibility, enforcement of administration measures along the northern coast of Chile requires ecological indicators to monitor the sustainability of Lessonia kelps. Over 2 years, density, biomass, recruitment, and size structure of Lessonia were sampled seasonally in coastal areas with different regimens of harvesting administration as follows: (1) Management Areas for Exploitation of Benthic Resources (MAEBR), (2) Open Access Areas (OAA), and (3) Marine Protected Areas without human intervention. The use of demographic parameters as ecological indicators allows discrimination between kelp beds where good harvesting practices have been applied by users (MAEBR), and areas where management recommendations have not been put in practice (OAA). The ecological indicators reinforced the concept of co-management in MAEBR as a viable harvesting administration system along the Chilean coast, and indicated a high-harvesting pressure in OAA. Moreover, together with other harvesting parameters, they could be useful to justify the application of other administration strategies, such as quotas or bans.
Año: 2014
Palabras claves: Kelp harvesting, Natural populations, Intertidal beds, Management, Conservation, Administration policies.
Referencia APA: Vega, J., Broitman, B., & Vásquez, J. (2014). Monitoring the sustainability of Lessonia nigrescens (Laminariales, Phaeophyceae) in northern Chile under strong harvest pressure. J Appl Phycol, 26(2), 791-801.
A test of large-scale reproductive migration in females of the amphidromous shrimp Macrobrachium acanthurus (Caridea : Palaemonidae) from south-eastern Brazil.
Bertini, G., Baeza, J., & Perez, E.
Macrobrachium acanthurus inhabits estuaries and rivers in the western Atlantic. It is not clear whether females migrate towards estuaries to hatch larvae, as reported for other congeneric shrimps. We tested whether females of M. acanthurus exhibit reproductive migrations. The population dynamics of this shrimp was studied in the Ribeira de Iguape River, Brazil. Four sites that differ in position with respect to the coast were sampled monthly during 2007. In M. acanthurus, reproduction was seasonal and reproductive intensity did not vary among study sites. Females brooding early and late embryos were found at all study sites during the reproductive season. No disappearance of reproductive females was observed at the study site located furthest away (~150 km) from the coast. Thus, reproductive females of M. acanthurus do not exhibit reproductive migrations towards estuaries to hatch larvae. Maturity in females was reached at smaller body sizes during the austral summer and spring compared with winter and autumn. Growth rate and body size was sex-specific; males grew slower but attained larger average and final body sizes than females. This information needs to be considered in assessing stocks and establishing sustainable management plans for M. acanthurus in Brazil.
Año: 2014
Palabras claves: Freshwater prawn, growth, maturity, reproduction, sex ratio.
Referencia APA: Bertini, G., Baeza, J., & Perez, E. (2014). A test of large-scale reproductive migration in females of the amphidromous shrimp Macrobrachium acanthurus (Caridea: Palaemonidae) from south-eastern Brazil. Mar. Freshwater Res.
Morphological, ultrastructural, and genetic characterization of coalescence in the intertidal and shallow subtidal kelps Lessonia spicata and L. berteroana (Laminariales, Heterokontophyta).
González, A., Borras-Chavez, R., Beltrán, J., Flores, V., Vásquez, J., & Santelices, B.
Coalescing macroalgae may fuse with conspecifics, forming genetically heterogeneous entities known as chimera. This process has been shown in taxa from roughly half the red algal orders and in the Codium species, a green alga. Field observations indicate that common and dominant kelps along central Chile exhibit a fused holdfast. We evaluated whether such fusions are true coalescence processes in Lessonia spicata and Lessonia berteroana. To this end, we characterized the ultrastructural event involved in holdfast fusion in the laboratory. Additionally, coalescence in natural populations was quantified by measuring the frequency of individuals with genetically heterogenic stipes within the same holdfast. Results indicate that coalescence appears as a frequent process in laboratory, mostly restricted to intraspecific fusions. During fusion, the meristodermatic cells located in the contact area modify their morphology and reduce the number of plastids, mitochondria, and cell inclusions. The cell wall becomes much thinner and develops plasmodesmata, enhancing communication with equivalent cells of the other coalescencing individual. Stipe genotyping indicates that there is a widespread occurrence of chimerism in both species and genetic heterogeneity is increasing directly with the increasing number of stipes. The combination of results suggests that kelp frequently coalesce in the field, and the histological response observed approaches that of red algae. Since kelps are part of the dominant vegetation in low intertidal and shallow subtidal beds, the adaptive values of coalescence in these species should be evaluated. It is concluded that coalescence and chimerism are evolutionary convergent processes, occurring in all three major groups of seaweeds.
Año: 2014
Palabras claves: Coalescence, Chimerism, Kelps, Lessonia, Microsatellites, Heterokontophyta.
Referencia APA: González, A., Borras-Chavez, R., Beltrán, J., Flores, V., Vásquez, J., & Santelices, B. (2014). Morphological, ultrastructural, and genetic characterization of coalescence in the intertidal and shallow subtidal kelps Lessonia spicata and L. berteroana (Laminariales, Heterokontophyta). J Appl Phycol, 26(2), 1107-1113.
Mass die-off of the cold-water coral Desmophyllum dianthus in the Chilean Patagonian fjord region.
Försterra, G., Häussermann, V., Laudien, J., Jantzen, C., Sellanes, J., & Muñoz, P.
In fjords and channels of the Chilean Patagonia, the solitary cold-water coral Desmophyllum dianthus (Esper, 1794) can be found in depths as shallow as 7 m as part of a deep-water emerging benthic community. In the Comau Fjord, one of three Chilean fjords where this species is forming large banks with multiple branched pseudo colonies on the steep rock walls, shallow water coral communities have been monitored for more than a decade. In 2012, a mass die-off was observed along 8.4 km of coast line and at least down to 70 m depth. Only specimens of D. dianthus were affected while other organisms, including two more scleractinian species, were not visibly damaged. The event coincides with exceptionally high efflux of methane and sulfide enriched water from cold vents in the rock walls at this site. Due to strongly increased salmon farming activity in the last decade, algae blooms have increased in frequency and intensity as a result of elevated primary production. We hypothesize and provide evidence that either harmful substances from the cold vents or hypoxia following an exceptionally strong algae bloom—or the synergistic effects of both—might have caused the mass mortality.
Año: 2014
Palabras claves:
Referencia APA: Försterra, G., Häussermann, V., Laudien, J., Jantzen, C., Sellanes, J., & Muñoz, P. (2014). Mass die-off of the cold-water coral Desmophyllum dianthus in the Chilean Patagonian fjord region. BMS, 90(3), 895-899.
Economic valuation of kelp forests in northern Chile: values of goods and services of the ecosystem.
Vásquez, J., Zuñiga, S., Tala, F., Piaget, N., Rodríguez, D., & Vega, J.
Kelp beds, besides being one of the most important benthic resources in northern Chile, provide a variety of environmental goods and services. In order to evaluate economically the wild kelp populations in northern Chile (26° to 32° S) more than simply their commercial value as a source of raw materials for alginate extraction, we used several economic indicators to holistically assess the value of a group of brown seaweeds of economic importance, Lessonia spp. and Macrocystis pyrifera: (1) market value of biomass as a source of raw material for extraction of alginic acid, (2) market value of associated species of economic importance, (3) value as a source of scientific information, (4) value as a climate buffer (CO2 capture and release of O2), (5) value of associated biodiversity (non-commercial species), (6) value as cultural heritage and (7) value as a reservoir of biodiversity. Existence values of kelp beds which estimate the willingness of citizens to pay and work without payment to preserve the ecosystem were calculated using the contingent valuation technique. The results indicate that kelp beds in northern Chile have a total value of US $540 million. Of this total, kelp fishery accounts for 75 % and associated-species fisheries account for 15 %. In this context, the economic value of Chilean kelp beds is mainly associated with the industry of alginate extraction. By contrast, existence value as a source of scientific information or environmental buffer for CO2 capture or O2 production represents only 9 % of the total value, representing a very low relative importance to society. The economic valuation of coastal resources and marine ecosystems is a complementary tool for decision making and implementation of public policies related to the conservation and sustainable exploitation of renewable resources and their ecosystems.
Año: 2014
Palabras claves: Kelp fishery, Phaeophyta, Administrative policies, Ecosystem goods and services, Conservation, Economic value.
Referencia APA: Vásquez, J., Zuñiga, S., Tala, F., Piaget, N., Rodríguez, D., & Vega, J. (2014). Economic valuation of kelp forests in northern Chile: values of goods and services of the ecosystem. J Appl Phycol, 26(2), 1081-1088.
Geochemistry of reduced fluids from shallow cold vents hosting chemosynthetic communities (Comau Fjord, Chilean Patagonia, ∼42°S).
Muñoz, P., Sellanes, J., Villalobos, K., Zapata-Hernández, G., Mayr, C., & Araya, K.
Reduced fluids from shallow-marine vents sustain chemosynthetic bacterial mats located at the base of the volcano Barranco Colorado in Comau Fjord (X-Huinay; 42°23.279′S, 72°27.635′W). We characterized the chemical environment in which these bacteria thrive. To this end, we analyzed CH4, ∑H2S, O2, DIC, and stable isotopes (δ13C, δ2H and δ18O) and compared them with readings taken at a control station (which lacks evidence of fluid venting and mat-forming bacteria). In addition, CTD measurements, chlorophyll-a, and nutrient analyses were performed. At depths of approximately 5–7 m, the water column exhibited a pycnocline that formed under the influence of fresh water discharges, especially during the summer season, which also affected the surface temperature. Bacterial mats and elemental sulfur flocs were observed in the vicinity of the vents (X-Huinay station), and higher concentrations of reduced compounds (CH4 and ∑H2S) were found in the vent fluids, in particular at a depth of 36 m. No significant differences in the temperatures of vent and ambient waters were detected. The bottom water close to the vents possessed notably low concentrations of reduced compounds, indicating a rapid and large-quantity dilution of the chemicals from vents. The surface water featured light isotopic values of δ2H and 18O due to the freshwater input from melting ice and precipitation. A linear mixing trend was observed between the freshwater (negative isotopic values) and the fjord bottom water (positive values) that was not influenced by vent fluid. This trend suggests that the venting water corresponds to the mixing among local meteoric water, spring water, and seawater. This result is relevant to understanding how freshwater and meteoric water influence the chemical composition of seawater and how this mixing could impact the marine biota in the vicinities of the vents.
Año: 2014
Palabras claves:
Referencia APA: Muñoz, P., Sellanes, J., Villalobos, K., Zapata-Hernández, G., Mayr, C., & Araya, K. (2014). Geochemistry of reduced fluids from shallow cold vents hosting chemosynthetic communities (Comau Fjord, Chilean Patagonia, ∼42°S). Progress In Oceanography, 129, 159-169.
Molecular phylogeny of hinge-beak shrimps (Decapoda: Caridea: Rhynchocinetes and Cinetorhynchus ) and allies: a formal test of familiar and generic monophyly using a multilocus phylogeny.
Baeza, J., Bauer, R., Okuno, J., & Thiel, M.
The Rhynchocinetidae (‘hinge-beak’ shrimps) is a family of marine caridean decapods with considerable variation in sexual dimorphism, male weaponry, mating tactics, and sexual systems. Thus, this group is an excellent model with which to analyse the evolution of these important characteristics, which are of interest not only in shrimps specifically but also in animal taxa in general. Yet, there exists no phylogenetic hypothesis, either molecular or morphological, for this taxon against which to test either the evolution of behavioural traits within the Rhynchocinetidae or its genealogical relationships with other caridean taxa. In this study, we tested (1) hypotheses on the phylogenetic relationships of rhynchocinetid shrimps, and (2) the efficacy of different (one-, two-, and three-phase) methods to generate a reliable phylogeny. Total genomic DNA was extracted from tissue samples taken from 17 species of Rhynchocinetidae and five other species currently or previously assigned to the same superfamily (Nematocarcinoidea); six species from other superfamilies were used as outgroups. Sequences from two nuclear genes (H3 and Enolase) and one mitochondrial gene (12S) were used to construct phylogenies. One-phase phylogenetic analyses (SATé-II) and classical two- and three-phase phylogenetic analyses were employed, using both maximum likelihood and Bayesian inference methods. Both a two-gene data set (H3 and Enolase) and a three-gene data set (H3, Enolase, 12S) were utilized to explore the relationships amongst the targeted species. These analyses showed that the superfamily Nematocarcinoidea, as currently accepted, is polyphyletic. Furthermore, the two major clades recognized by the SATé-II analysis are clearly concordant with the genera Rhynchocinetes and Cinetorhynchus, which are currently recognized in the morphological-based classification (implicit phylogeny) as composing the family Rhynchocinetidae. The SATé-II method is considered superior to the other phylogenetic analyses employed, which failed to recognize these two major clades. Studies using more genes and a more complete species data set are needed to test yet unresolved inter- and intrafamilial systematic and evolutionary questions about this remarkable clade of caridean shrimps. © 2014 The Linnean Society of London
Año: 2014
Palabras claves: Bayesian hypothesis testing; Crustacea; SATé-II.
Referencia APA: Baeza, J., Bauer, R., Okuno, J., & Thiel, M. (2014). Molecular phylogeny of hinge-beak shrimps (Decapoda: Caridea: Rhynchocinetes and Cinetorhynchus) and allies: a formal test of familiar and generic monophyly using a multilocus phylogeny. Zool J Linn Soc, 172(2), 426-450.
Morphological, physiological and reproductive conditions of rafting bull kelp (Durvillaea antarctica) in northern-central Chile (30°S).
Tala, F., Gómez, I., Luna-Jorquera, G. et al.
The bull kelp Durvillaea antarctica is a common floating alga in the southern hemisphere, but despite the ecological and biogeographic importance of kelp rafts, little is known about the responses of detached kelps to the conditions at the sea surface. The morphological, physiological and reproductive performances of D. antarctica rafts in the Coastal System of Coquimbo, Chile (CSC, ~30°S), were examined during winter and summer of two successive years (2010/11 and 2011/12). Epibionts (Lepas spp.) that only attach to floating objects were used as indicator for the floating time of kelp rafts. Photosynthetic efficiency and reproductive maturity of both benthic and floating algae varied seasonally, with a stronger decrease in summer than in winter. Blade size (measured as weight proportion of kelp individuals), phlorotannin concentrations and antioxidant activities were lower in floating than in benthic algae. Environmental conditions and floating time affected the blade tissues, with stronger negative effects during summer. These results confirm that floating persistence of D. antarctica in the CSC is suppressed during the summer months, which indicates that the dispersal potential of this (and other) floating algae varies seasonally.
Año: 2013
Palabras claves:
Referencia APA: Tala, F., Gómez, I., Luna-Jorquera, G. et al. (2013). Morphological, physiological and reproductive conditions of rafting bull kelp (Durvillaea antarctica) in northern-central Chile (30°S). Marine Biology, 160(6), 1339–1351.
Effects of isolation and fishing on the marine ecosystems of Easter Island and Salas y Gómez, Chile.
Friedlander, A., Ballesteros, E., Beets, J., Berkenpas, E., Gaymer, C., Gorny, M., & Sala, E.
An expedition to Salas y Gómez and Easter islands was conducted to develop a comprehensive baseline of the nearshore marine ecosystem, to survey seamounts of the recently created Motu Motiro Hiva Marine Park (MMHMP) – a no-take marine reserve of 150 000 km2 – and to compare these results with Easter Island where the marine ecosystem is similar but has no marine protection.
Live coral cover was surprisingly high at both Easter Island (53%) and Salas y Gómez (44%), especially considering their sub-tropical location, high wave energy environments, and geographic isolation.
Endemic and regionally-endemic species comprised 77% of the fish abundance at Easter Island and 73% at Salas y Gómez. Fish biomass at Salas y Gómez was relatively high (1.2 t ha-1) and included a large proportion of apex predators (43%), whereas at Easter Island it was almost three times lower (0.45 t ha-1) with large predators accounting for less than 2% of the biomass, despite good habitat quality.
The large cohort of small sharks and the absence of larger sharks at Salas y Gómez suggest mesopredator release consistent with recent shark fishing. The fish fauna at the seamounts between Easter Island and Salas y Gómez, outside of MMHMP, harboured 46% endemic species, including a new species of damselfish (Chromis sp. nov.) and probably a new species of Chimaera (Hydrolagus). Numerous seamounts adjacent to Salas y Gómez are currently not included in the MMHMP.
This expedition highlights the high biodiversity value of this remote part of the Pacific owing to the uniqueness (endemicity) of the fauna, large apex predator biomass, and geographic isolation.
Año: 2013
Palabras claves: Coral; biodiversity; no-take marine reserve; algae; fish; fishing.
Referencia APA: Friedlander, A., Ballesteros, E., Beets, J., Berkenpas, E., Gaymer, C., Gorny, M., & Sala, E. (2013). Effects of isolation and fishing on the marine ecosystems of Easter Island and Salas y Gómez, Chile. Aquatic Conserv: Mar. Freshw. Ecosyst., 23(4), 515-531.
Demography and feeding behavior of the kelp crab Taliepus marginatus in subtidal habitats dominated by the kelps Macrocystis pyrifera or Lessonia trabeculata.
Jofré Madariaga, D., Ortiz, M., & Thiel, M.
We studied the population and feeding ecology of the kelp crab Taliepus marginatus in subtidal kelp forests dominated by either of two morphologically different kelp species (Macrocystis pyrifera or Lessonia trabeculata) in northern Chile. The sizes and abundances of T. marginatus differed between the two kelp habitats. Kelp crabs were more abundant in the M. pyrifera forest than in the L. trabeculata forest. Size-frequency distributions showed that juvenile and immature crabs were more common in the M. pyrifera forest than in the L. trabeculata forest, where reproductive adults predominated. The smaller crabs in the M. pyrifera habitat also consumed a higher proportion of kelp tissues than the larger crabs in the L. trabeculata habitat, which had a higher proportion of animal food in their diet. In both kelp forests, individuals of T. marginatus showed a similar pattern of nocturnal feeding over a 24-h period, consuming more food at night than during the day. The more complex and dense forests of M. pyrifera appear to present better nursery habitats for juvenile kelp crabs than the more open and less dense forests dominated by L. trabeculata. These results suggest that the role of the two kelp habitats for T. marginatus varies during the life cycle of the kelp crabs, with M. pyrifera tending to have nursery function and L. trabeculata being more suitable as a reproductive habitat.
Año: 2013
Palabras claves: Habitat use; nursery habitat; reproductive habitat; diet.
Referencia APA: Jofré Madariaga, D., Ortiz, M., & Thiel, M. (2013). Demography and feeding behavior of the kelp crab Taliepus marginatus in subtidal habitats dominated by the kelps Macrocystis pyrifera or Lessonia trabeculata. Invertebrate Biology, 132(2), 133-144.