Using scales to clarify the transition from blue-phase to brown-phase fingerling in Notothenia rossii from the South Shetland Islands

Scales and whole otoliths were read for age determination in early stages of Notothenia rossii caught in Potter Cove, South Shetland Islands, in summer seasons 2003-2006 and 2008. The sample comprised blue-phase pelagic fingerlings of 7.0-7.6 cm (TL) of age group 0 year and demersal brown-phase fingerlings/juveniles of 8.5-20.9 cm and predominant age groups 1-2 years. Counting of sclerites facilitated the interpretation of the rings, particularly in the central scale. To clarify two previous issues of controversy, we deduce that the duration of the offshore pelagic blue-phase fingerling stage is less than one year before migration to the nearshore demersal habitat. Furthermore, the first well-defined ring in scales corresponded to the first annulus, while a contiguous ring was a secondary ring sometimes deposited after the first winter during the second year of life, attributable to a shift of habitat from pelagic to demersal. A von Bertalanffy growth curve was computed by combining age/length data of the juvenile phase of N. rossii from this and a previous study at Potter Cove with literature data from the offshore adult population, resulting in the following equation: Lt = 86.9 (1-e-0.091(t-0.668)).Fil: Barrera Oro, Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Alescio, Nadia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Moreira, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Marschoff, Enrique Ricardo. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentin

Slow recovery of previously depleted demersal fish at the South Shetland Islands, 1983-2010

Following seals and baleen whales prior to the 1970s, demersal fish stocks were depleted off the South Shetland Islands by intensive industrial fishing during the late 1970s to early 1980s. Little has been reported since about how these stocks have fared, after international agreement closed this fishery in 1990. We report changes in size and abundance of the commercially exploited Notothenia rossii and Gobionotothen gibberifrons relative to the ecologically similar but unexploited Notothenia coriiceps at Potter Cove, South Shetland Islands, over a 28-yr period, 1983?2010. N. rossii abundance declined from 1983 to 1991, and an increase in mean size during 1983?1984 is consistent with weak cohorts during preceding years. Modal age changed from 2?3 to 6?7 yr. Length data of G. gibberifrons, available from 1986, exhibited a similar pattern, showing a decrease until 1991?1992. After a period of relative stability (1992?1994), a sharp increase in length and a continued decline in relative abundance indicated low recruitment. The length?frequency distribution of unexploited N. coriiceps throughout the whole period showed no change in modal size or mean length of the fish. We relate these patterns to the fishery and suggest that a further two decades will lapse before these stocks recover. Using the South Shetland fisheries as an example, current management rules for Southern Ocean fisheries, deemed to be precautionary and disallowing depletion beyond which a stock can recover in 2?3 decades, may be unrealistic in an ocean profoundly altered by numerous stock depletions and rapid climate change.Fil: Marschoff, Enrique Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Barrera Oro, Esteban. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Alescio, Nadia Soledad. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ainley, David G.. No especifíca

Avance en el diagnóstico de enfermedades neurológicas : una señal de alerta temprana

Fil: Serra, Jorge A. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina.Fil: Domínguez, Raúl O. Universidad de Buenos Aires, Facultad de Medicina; Argentina.Fil: Lustig, Eugenia S. de. Universidad de Buenos Aires. Instituto Roffo; Argentina.Fil: Marschoff, Enrique R. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.A las graves consecuencias que ocasionan para las personas que las padecen, algunas enfermedades\nneurológicas, como el mal de Alzheimer, presentan además otro inconveniente: su detección resulta\nmuy dificultosa y se basa fundamentalmente en la evaluación médica. Luego de años de trabajo, un\ngrupo multidisciplinario de investigadores de la UBA ha logrado un promisorio avance que permitiría\ndiagnosticar y diferenciar entre sí a este tipo de dolencias, a través de un análisis de sangre que\nmediría el estrés oxidativo de los posibles afectados

Density and distribution of euphausiid larvae in the Scotia Sea in the 2011 summer

Monitoring of early euphausiid larvae provides valuable information on the mechanisms involved in recruitment to the adult populations. As the Antarctic is undergoing rapid environmental change, these mechanisms are key to ecosystem-based management of the krill fishery. We analyzed the distribution and abundance of early euphausiid larvae (calyptopes I to late furciliae) from 76 plankton samples from surface to 300 m depth in the Atlantic sector in January 2011 in relation with a previous survey and published information. Thysanoessa macrura (mean density: 209 ind m−2) dominated the sampling while Euphausia superba (mean density: 13.63 ind m−2) and Euphausia frigida (mean density: 10.05 ind m−2) were also present. T. macrura density increased while E. superba experienced a high decrease respect to historical data. Clustering of stations and correspondence analysis showed that the associations of larvae and water masses are in agreement with literature reports, so the differences on the abundance of early larvae are within the observed variability and cannot be attributed to any single factor, suggesting that it is due to more subtle changes such as the stability of the water column and/or vorticity in the fronts.Fil: Rombola, Emilce Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Franzosi, C.. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Tosonotto, G.. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Vivequin, Sandra Maria. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Alder, Viviana Andrea. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Marschoff, Enrique Ricardo. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentin

Estrategias reproductivas de Eufausiaceos (Euphausiacea, crustácea) antárticos como mecanismo regulador de la distribución

Fil:Marschoff, Enrique R.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Changing status of three notothenioid fish at the South Shetland Islands (1983–2016) after impacts of the 1970–80s commercial fishery

Owing to commercial fishing during the late 1970s/early 1980s, targeted notothenioid species had become depleted around the South Shetland Islands. Herein we report subsequent changes in the prevalence of three species, Notothenia rossii, Gobionotothen gibberifrons and Notothenia coriiceps in Potter Cove, King George Islands/Isla 25 de Mayo, in a 33-year effort to monitor recovery. N. rossii and G. gibberifrons had been severely impacted by industrial fishing but in offshore waters N. coriiceps had never been commercially fished; however, all three species exhibit similar nearshore habitats and life history. We examined composition in trammel net catches during 2012–2016, augmenting a time series started in 1983. Our inshore results were consistent with those from offshore bottom trawl sampling in 2007 and 2012 around the South Shetland Islands: (1) continued increase in the abundance of N. rossii; (2) further decline in G. gibberifrons recruitment evidenced by low proportions of juvenile fish; and (3) a high abundance of N. coriiceps. Reasons for lack of recovery in G. gibberifrons remain obscure but seemingly relate to the dramatically changing ecosystem of the region due in part to climate as well as recovery among previously depleted upper trophic level species. Our results are also consistent with trends reported in seabirds that feed on juveniles of these notothenioids: decrease in the areas commercially fished. Under the regulation of CCAMLR, commercial fishing for finfish in the South Shetland Islands region (FAO Subarea 48.1) remains prohibited since 1991; results indicate that it cannot be reinstated.Fil: Barrera Oro, Esteban. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Marschoff, Enrique Ricardo. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Abramson, David. H.T. Harvey and Associates; Estados Unido