Estructuras agrarias provinciales con datos censales y fuentes alternativas

La relevancia que tiene en la economía argentina el sector agropecuario en tanto proveedor de divisas vía exportaciones y fijador de precios de bienes salario, requiere contar con buenos diagnósticos para el diseño de políticas. Los Censos Agropecuarios constituyen una fuente invalorable de información para elaborar esos diagnósticos ya que permiten dar cuenta de la cantidad y superficie de las explotaciones agropecuarias y forestales, de las formas de tenencia de la tierra, de su distribución, de las existencias ganaderas y tipo de cultivos, de la dotación de bienes de capital y la cantidad de trabajadores empleados, entre otras variables que resultan significativas al momento de abordar el análisis de la estructura agraria. En Argentina esos censos, se han realizado en forma discontinua y no siempre con resultados incuestionables, de allí la necesidad de recurrir, en ciertos casos, a otras fuentes de información. Del último censo, realizado en 2018, sólo se cuentan con resultados preliminares. La Cátedra ha convocado a un grupo de colegas de diferentes provincias para analizar y comparar los datos censales de 2002 y 2018. En este número presentamos los informes realizados para las provincias de La Pampa, Mendoza y San Juan.The relevance the agricultural and livestock sector has in the Argentine economy as a provider of foreign exchange through exports as well as being price setters of wage goods, requires having good diagnoses for the design of policies. The Agricultural and Livestock Censuses are a valuable source of information for the elaboration of these diagnoses, since they make it possible to account for the quantity and area of agricultural and forestry holdings, for forms of land tenure, its distribution, of livestock stocks and types of crops, the provision of capital goods and the number of workers employed, among other variables that are significant when considering the analysis of the agrarian structure. in Argentina these censuses have been carried out discontinuously and not always with unquestionable results, hence the need to rely on other sources of information in certain cases. Of the last census, carried out in 2018, only preliminary results are available. The professorship has summoned a group of colleagues from different provinces to analyze and compare the census data from 2002 and 2018. in this issue we present the reports made for the provinces of La Pampa, Mendoza and San Juan.EEA AnguilFil: Torrado, Juan Jose. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil. Agencia de Extensión Rural Victorica; ArgentinaFil: Mathey, Marta Daniela. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; ArgentinaFil: Van den Bosch, Maria Eugenia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; ArgentinaFil: Tapella, Pablo Federico. Universidad Nacional de San Juan. Instituto de Investigaciones Socioeconómicas; Argentin

Distribución de invertebrados bentónicos en el Canal Beagle, Argentina

Se determinó la distribución batimétrica, espacial y temporal de la abundancia y biomasa de invertebratrados bentónicos del Canal Beagle, como también su producción secundaria. Las muestras se tomaron estacionalmente en tres lugares diferentes del Canal Beagle y en dos estratos de profundidad, 15-40 m y 70-259 m. Se identificó un total de 32.686 individuos distribuidos en 30 grupos taxonómicos. Además, 4 taxones se cuantificaron sólo en términos de biomasa. La abundancia y biomasa de invertebrados fue diferente con la profundidad. La producción secundaria en este estrato fue 0,59 ±0,51 kJ·m-2año-1 mientras que a 70-259 m disminuyó a 0,09 ±0,08 kJ·m-2año-1. Por el contrario, la tasa P/B mostró un incremento positivo con la profundidad. A su vez, no se observaron variaciones estacionales en la producción secundaria del macrozoobentos. Parámetros asociados directamente con la profundidad podrían estructurar los ensambles macrobentónicos en el Canal Beagle.Bathymetric and spatio-temporal distributions of both abundance and biomass as well as secondary production of benthic invertebrates in the Beagle Channel were determined. The sampling stations were seasonally placed in three different areas in the Beagle Channel at two depth ranges, 15-40 m and 70-259 m. A total of 32,686 specimens distributed in 30 taxonomic groups were identified. In addition, 4 taxa were quantified only in terms of biomass. The invertebrate abundance and biomass were different with depth. Secondary production at this range was 0.59 ±0.51 kJ·m-2 year-1 whereas it decreased to 0.09 ±0.08 kJ·m-2 year-1 at 70-259 m. In contrast to secondary production, P/B ratio showed a positive increment with depth. Furthermore, seasonal variations were not observed in secondary production of the macrozoobenthos. Parameters directly associated with depth could be involved in structuring the macrobenthic assemblages in the Beagle Channel.Fil: Diez, Mariano Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Romero, Maria Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Obenat, Sandra Mabel. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Albano, Mariano Javier. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Tapella, Pablo Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin

Evolutionary trade-offs in osmotic and ionic regulation and expression of gill ion transporter genes in high latitude, cold clime Neotropical crabs from the ‘end of the world’

Osmoregulatory findings on crabs from high Neotropical latitudes are entirely lacking. Seeking to identify the consequences of evolution at low temperature, we examined hyperosmotic/hypo-osmotic and ionic regulation and gill ion transporter gene expression in two sub-Antarctic Eubrachyura from the Beagle Channel, Tierra del Fuego. Despite sharing the same osmotic niche, Acanthocyclus albatrossis tolerates a wider salinity range (2–65% S) than Halicarcinus planatus (5–60% S); their respective lower and upper critical salinities are 4% and 12% S, and 63% and 50% S. Acanthocyclus albatrossis is a weak hyperosmotic regulator, while H. planatus hyperosmoconforms; isosmotic points are 1380 and ∼1340 mOsm kg−1 H2O, respectively. Both crabs hyper/hypo-regulate [Cl−] well with iso-chloride points at 452 and 316 mmol l−1 Cl−, respectively. [Na+] is hyper-regulated at all salinities. mRNA expression of gill Na+/K+-ATPase is salinity sensitive in A. albatrossis, increasing ∼1.9-fold at 5% compared with 30% S, decreasing at 40–60% S. Expression in H. planatus is very low salinity sensitive, increasing ∼4.7-fold over 30% S, but decreasing at 50% S. V-ATPase expression decreases in A. albatrossis at low and high salinities as in H. planatus. Na+/K+/ 2Cl− symporter expression in A. albatrossis increases 2.6-fold at 5% S, but decreases at 60% S versus 30% S. Chloride uptake may be mediated by increased Na+/K+/2Cl− expression but Cl− secretion is independent of symporter expression. These unrelated eubrachyurans exhibit similar systemic osmoregulatory characteristics and are better adapted to dilute media; however, the expression of genes underlying ion uptake and secretion shows marked interspecific divergence. Cold clime crabs may limit osmoregulatory energy expenditure by hyper/hypo-regulating hemolymph [Cl−] alone, apportioning resources for other energy-demanding processes.Fil: McNamara, John Campbell. Universidade de Sao Paulo; BrasilFil: Maraschi, Anieli Cristina. Universidade de Sao Paulo; BrasilFil: Tapella, Pablo Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Romero, Maria Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin

Decapods of the Southern Tip of South America and the Marine Protected Area Namuncurá–Burdwood Bank: A Nearshore–Offshore Comparison

The Marine Protected Area (MPA) Namuncurá−Burdwood Bank was created in 2013 to protect the benthic community. After five years of multidisciplinary research, it was reorganized, and a second, contiguous MPA Namuncurá−Burdwood Bank II was created. The objectives of this study were to evaluate the decapod assemblages in both the previous and current management zones and to compare them with the neighboring areas of southern South America. The decapod fauna was studied integratively by comparing captured species onboard scientific expeditions with online records. Our study showed that the original design of the MPAN−BB had the lowest decapod species richness. However, the constitution of a larger protected area, including the slope, increased the species richness, with unique records of Campylonotus arntzianus and Lithodes couesi. The MPA could be considered ecologically representative as it shares various species with the nearby areas (the Beagle Channel and the Atlantic). Furthermore, we theorize it could act as a “hub” for decapod species as marine currents provide the Burdwood Bank with new individuals from the west and disperse them northward to the Patagonian Shelf and eastward to the Scotia Arc. This result shows the great value of protecting this area, ensuring the conservation of the decapod fauna of southern South America

Suspended mesh-bags enclosures for Southern King Crab Lithodes santolla (Molina 1782) larvae and juvenile culture in the sea

The potential for using suspended mesh-bags for larval/juvenile southern king crab (Lithodes santolla) aquaculture was assessed. Three early stages (Zoea, Megalopa and first juvenile, or C1) were confined for 45–65 days in mesh-bags near the sea-bottom. As L. santolla starts feeding when it reaches the first juvenile stage, the effect of biofouling presence was also tested in the C1 culture. Extreme vulnerability of the first larval stage was observed, as no live larvae were recovered when Z1 were used as seeds. On the other hand, survival of Megalopa and C1 reached 19.76 ± 1.08 and 30.00 ± 3.50%, respectively, and both C1 juvenile survival and growth were enhanced significantly by the presence of biofouling on the bags. These results indicate that suspended mesh-bags have potential for L. santolla juvenile culture in the sea. We suggest a 2-step culture process: indoor culturing of the three Zoea stages, and subsequently sea culture starting at the Megalopa stage. Once Megalopa molt to the C1 stage in the field, the already fouled culture system (mesh-bags) would allow newly molted crabs to feed. Further research should be directed towards sea culture optimization, including feeding requirements for bigger crabs, to implement a future stock enhancement program for king crabs in the Beagle Channel.Fil: Sotelano, María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Lovrich, Gustavo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Di Salvatore, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Florentin, Olga Viviana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Giamportone, Ariel Lujan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Tapella, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin