UCN-CEAZA
Impact of grazing by the sea urchin Tetrapygus niger on the kelp Lessonia trabeculata in Northern Chile.
Perreault, M., Borgeaud, I., & Gaymer, C.
The ability of sea urchins to destroy kelp forests, leaving large areas stripped of vegetation and covered by sparse calcareous algae is well known. The reduction in active predators of sea urchins combined with their broad diet makes them an important factor in the structuring of subtidal benthic marine systems. In central and northern Chile, the sea urchin Tetrapygus niger is known to reduce the spread of the subtidal kelp Lessonia trabeculata. However, its impact on the different development stages of L. trabeculata has never been quantified or compared to other possible causes of the loss of material. The objective of this study was to quantify the grazing impact of T. niger on L. trabeculata at different stages of development (recruits, juveniles and adults). An exclusion experiment was conducted to evaluate the grazing effect of T. niger on kelp recruitment within a kelp bed, and kelp transplant experiments were conducted to quantify T. niger's impact on the stipes and fronds of juvenile and adult L. trabeculata. Our results showed that under natural sea urchin densities (10 ind. m− 2), T. niger prevented the recruitment of L. trabeculata. Tetrapygus niger completely consumed juvenile plants but only attacked the stipes of adult plants. Tetrapygus niger seems to use different feeding strategies depending on the ontogeny of the plant. Lessonia trabeculata seems unable to defend itself against the impact of intensive grazing by sea urchins, which may be the primary source of mortality of recruits and juveniles of L. trabeculata. However, T. niger's impact on adult plants is limited and shared with other herbivores that graze the fronds, such as fishes and spider crabs.
Año: 2014
Palabras claves: Chile; Herbivory; Lessonia trabeculata; Rocky subtidal; Sea urchin–kelp interaction; Tetrapygus niger.
Referencia APA: Perreault, M., Borgeaud, I., & Gaymer, C. (2014). Impact of grazing by the sea urchin Tetrapygus niger on the kelp Lessonia trabeculata in Northern Chile. Journal Of Experimental Marine Biology And Ecology, 453, 22-27.
Social-Ecological Collapse: TURF Governance in the Context of Highly Variable Resources in Chile.
Aburto, J., Stotz, W., & Cundill, G.
In Chile, a Territorial User Rights for Fisheries system was developed to manage benthic fisheries. This system is referred to as Management Areas for the Exploitation of Benthic Resources. Management areas involved a shift from top-down control by governments to comanagement. We have analyzed the effects of a highly variable fishery, characterized by boom-and-bust cycles, on the governance of local institutions designed for resource management. We focused on a case study in north central Chile, in which the surf clam fishery experienced high levels of variability when the fishery was in an open access system. The management areas were established for the fishery in 1999. As a result, a set of rules for the fishery were created and enforced by fishers and local fishery authorities. Despite intense efforts on the part of all stakeholders, the fishery collapsed after three years of management area policy. This approach has been shown to be an effective management option for other species; however, for resources with boom-and-bust cycles, it is important to understand the response pattern of users confronting this spatial and temporal variability before the establishment of territorial user rights. Defining the appropriate spatial scale of the territorial rights could allow fishers to switch among different surf clam beds to maintain their livelihood and support the sustainability of local institutions for resource management.
Año: 2014
Palabras claves: Governance; management area; small-scale fishery; social-ecological; TURF.
Referencia APA: Aburto, J., Stotz, W., & Cundill, G. (2014). Social-Ecological Collapse: TURF Governance in the Context of Highly Variable Resources in Chile. Ecology And Society, 19(1).
Collaboration and knowledge networks in coastal resources management: How critical stakeholders interact for multiple-use marine protected area implementation.
Cárcamo, P., Garay-Flühmann, R., & Gaymer, C.
Recent studies have shown that social networks and their properties are key in the search for explanations for the success in the governance and management of natural resources. We investigated the structure and properties of inter-organizational social networks involved in the use and management of natural resources in a coastal marine ecosystem in northern Chile proposed as a possible marine protected area. We explored two network configurations: i) relations of collaboration and ii) relations of transfer and exchange of scientific knowledge and information useful to the management of natural resources and the decision-making process involved. Both networks showed little cohesion, with low values of centralization and density indicating a low flow of collaborative and exchange relations among different stakeholders. The knowledge network achieved greater levels of centralization than the collaboration network. National government agencies and fishermen organizations were the most powerful stakeholders in the collaboration network. National government agencies and universities were the most powerful stakeholders in the knowledge network. We found a disconnected network when analyzing the flows of collaboration and knowledge between different administrative operation levels that potentially would hamper the governance of this area. On the other hand, we identified stakeholders that would help to connect the network (bridging stakeholders). Additional analysis of stakeholders using influence-capacity matrix allowed us to identify key stakeholders for planning and implementing the new marine protected area, compare results with the network analysis, and propose network interventions. We propose combining Social Network Analysis with other methods of stakeholder analysis to produce more practical and implementable results. Our results are relevant for future interventions aimed at improving or implementing management and governance of coastal areas.
Año: 2014
Palabras claves:
Referencia APA: Cárcamo, P., Garay-Flühmann, R., & Gaymer, C. (2014). Collaboration and knowledge networks in coastal resources management: How critical stakeholders interact for multiple-use marine protected area implementation. Ocean & Coastal Management, 91, 5-16.
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: 2015
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. (2014). 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.
Effects of the Discharge of Iron Ore Tailings on Subtidal Rocky-Bottom Communities in Northern Chile.
González, S., Stotz, W., & Lancellotti, D.
Some of the many mining operations that exist in northern Chile dispose their mine tailings directly into the sea. Little is known about the effects of these tailings on shallow rocky subtidal communities. This study reports these effects for an iron ore pelletization plant that has discharged for ca. 23 years in the intertidal of a cove on the exposed rocky coast of northern Chile, generating high turbidity in the water column and deposit of sediments on the bottom. A nonparametric multidimensional scaling (nMDS) ordination analysis for the species of the rocky subtidal communities, based on the Bray-Curtis dissimilarity index, showed great differences, the affected communities being dominated by incrusting invertebrates, whereas the unaffected areas at the same depth had kelp beds. The effects were observed only close to the discharge and were not observed in the more shallow water communities, which in affected and unaffected areas consisted of barren grounds dominated by calcareous algae and sea urchins. The effect on the vertical zonation pattern of communities did not produce differences in the effective diversity, which turned out to be similar among affected and control sites. This occurred because of the replacement, more than the elimination, of species on affected sites. This type of study, in which information is generally maintained in reports only seen by industry and governments, needs to be published to contribute to a more comprehensive database for the improvement of decision-making processes regarding coastal subtidal rocky communities and the effects of human activities on these environments.
Año: 2014
Palabras claves: Mining activities on the coast, discharge of suspended solids, effect of turbidity, marine assemblages, kelp beds, barren grounds, Chilean coast
Referencia APA: González, S., Stotz, W., & Lancellotti, D. (2014). Effects of the Discharge of Iron Ore Tailings on Subtidal Rocky-Bottom Communities in Northern Chile. Journal Of Coastal Research, 295, 500-514.
The Status of Kelp Exploitation and Marine Agronomy, with Emphasis on Macrocystis pyrifera, in Chile.
Buschmann, A., Prescott, S., Potin, P., Faugeron, S., Vásquez, J., & Camus, C. et al.
Kelp cultivation started in Japan, China and Korea, mainly for human consumption; new applications are still expanding. In Chile, three ‘wild’ Lessonia species and Macrocystis pyrifera are under a strong and increasing pressure of exploitation mainly for alginate production and as a source of feed for abalone. Regulatory restrictions for kelp exploitation and the increased demand for biomass provided a positive environment for the installation of a kelp farming industry. Pilot-production studies demonstrated that 200 tonnes (fresh)/ha/year can be achieved and genetic diversity and breeding studies suggested that this volume could be increased. Kelp disease research is a necessary condition for securing the future development of this industry, as are environmental studies on the impacts of large-scale aquaculture. Beyond the positive bioremediation, ecosystem service effects that kelp farming can provide, especially in a region such as in southern Chile, where intensive salmon and mussel cultivation occurs. Life Cycle Assessment suggests that the energy returns on investment in kelp farming are positive, but more detailed data are still required.
Año: 2014
Palabras claves: Kelp exploitation and farming; Life cycle assessment; Macrocystis pyrifera; Seaweed diseases; Seaweed farming environmental impacts.
Referencia APA: Buschmann, A., Prescott, S., Potin, P., Faugeron, S., Vásquez, J., & Camus, C. et al. (2014). The Status of Kelp Exploitation and Marine Agronomy, with Emphasis on Macrocystis pyrifera, in Chile. Advances In Botanical Research, 161-188
Effects of predation on diel activity and habitat use of the coral-reef shrimp Cinetorhynchus hendersoni (Rhynchocinetidae).
Ory, N., Dudgeon, D., Duprey, N., & Thiel, M.
Nonlethal effects of predators on prey behaviour are still poorly understood, although they may have cascading effects through food webs. Underwater observations and experiments were conducted on a shallow fringing coral reef in Malaysia to examine whether predation risks affect diel activity, habitat use, and survival of the rhynchocinetid shrimp Cinetorhynchus hendersoni. The study site was within a protected area where predatory fish were abundant. Visual surveys and tethering experiments were conducted in April–May 2010 to compare the abundance of shrimps and predatory fishes and the relative predation intensity on shrimps during day and night. Shrimps were not seen during the day but came out of refuges at night, when the risk of being eaten was reduced. Shrimp preferences for substrata of different complexities and types were examined at night when they could be seen on the reef; complex substrata were preferred, while simple substrata were avoided. Shrimps were abundant on high-complexity columnar–foliate Porites rus, but tended to make little use of branching Acropora spp. Subsequent tethering experiments, conducted during daytime in June 2013, compared the relative mortality of shrimps on simple (sand–rubble, massive Porites spp.) and complex (P. rus, branching Acropora spp.) substrata under different predation risk scenarios (i.e., different tether lengths and exposure durations). The mortality of shrimps with short tethers (high risk) was high on all substrata while, under low and intermediate predation risks (long tethers), shrimp mortality was reduced on complex corals relative to that on sand–rubble or massive Porites spp. Overall, mortality was lowest on P. rus. Our study indicates that predation risks constrain shrimp activity and habitat choice, forcing them to hide deep inside complex substrata during the day. Such behavioural responses to predation risks and their consequences for the trophic role of invertebrate mesoconsumers warrant further investigation, especially in areas where predatory fishes have been overexploited.
Año: 2014
Palabras claves: Rhynchocinetid shrimps, Habitat complexity, Substratum structure, Predator–prey interactions, Risk effects,Tethering.
Referencia APA: Ory, N., Dudgeon, D., Duprey, N., & Thiel, M. (2014). Effects of predation on diel activity and habitat use of the coral-reef shrimp Cinetorhynchus hendersoni (Rhynchocinetidae). Coral Reefs, 33(3), 639-650.
Formulated diets for giant chilean frog Calyptocephalella gayi tadpoles
Toledo, P., Suazo, R., & Viana, M.
In this study, we conducted an experiment to evaluate the overall effect of novel diets on the growth, metamorphosis and survival of tadpoles of the endangered giant Chilean frog Calyptocephalella gayi (previously known as Caudiverbera caudiverbera) to evaluate the potential of this species for culture and repopulation purposes. Using fishmeal as the main protein source with a substitution of either scallop viscera or Spirulina meal, three treatments were formulated to contain similar amounts of protein and energy. The experiment was run for 75 days, after which the tadpoles showed no significant differences among treatments in terms of their growth or survival. This is the first study to report positive effects of different diets on the growth and survival of tadpoles of the giant Chilean frog. Therefore, it might be possible to extend the farming of Calyptocephalella gayi for human consumption and repopulation. Nevertheless, more efforts are needed to understand their nutritional requirements to formulate appropriate diets for this endangered frog.
Año: 2014
Palabras claves: Artificial diet, nutrition, protein sources, Spirulina meal, survival.
Referencia APA: Toledo, P., Suazo, R., & Viana, M. (2014). Formulated diets for giant chilean frog Calyptocephalella gayi tadpoles. Ciencia E Investigación Agraria, 41(1), 3-4.
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.