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La ballena franca del sur, Eubalaena australis (Desmoulins, 1822) en aguas chilenas: análisis de sus registros desde 1976 a 2008Southern right whales, Eubalaena australis (Desmoulins, 1822

RESUMENSe presenta la serie de temperaturas de Punta Arenas correspondientes a 120 años, en un periodo que va desde 1888 hasta el 2007. Se analizan las variaciones que ha tenido este parámetro atmosférico a través de estos años, concluyéndose que han ocurrido periodos intercalados de alta y de bajas temperaturas en torno a su valor medio. Respecto a su tendencia y en referencia al valor promedio, es más bien estable, aunque si se considera una regresión lineal, ésta muestra un leve enfriamiento durante estos 120 años. Un análisis estacional de esta variable muestra algunos matices respecto al comportamiento anual. Se analizan por separado las series de medias de las máximas y de las mínimas mensuales y se hace su comparación con las medias por estación del año en cada uno de éstas. Finalmente se analizan los valores extremos mensuales que ha tenido la temperatura en la ciudad y se presentan los valores más frecuentes que éstas han tenido en este periodo, así como los valores récord alcanzados.Palabras clave: Punta Arenas, temperatura. ABSTRACTA sequence of temperature records from Punta Arenas for the 120 year period 1888 -2007 are presented. The analyses of how temperature has varied over the years has concluded that there have been periods when the temperature has been below and above the median. A linear regression performed on the data showed that the temperature has slightly cooled over the 120 years. From a seasonal analysis of temperature, there were variable intra-seasonal differences between years. Mean monthly means of maximum and minimum temperature are compared by station and year. The frequency, occurrence and extremes of monthly temperatures in Punta Arenas over the period are presented.

ABSTRACT. The Aysén region (43°-47ºS) has been prone to intensive summer blooms of toxic microalgae and complex toxin profiles in the shellfish. However, their winter distribution, toxin profile, and resting cysts in sediments are poorly known. Frequently detected toxins are: Paralytic Shellfish Toxins (PST); lipophilic toxins, including Diarrheic Shellfish Toxins (DST), Amnesic Shellfish Toxin or Domoic Acid (DA). During a cruise, carried out in winter 2012, samples were collected at 24 stations for phytoplankton analysis and analysis of toxins in mollusks, and at 5 stations, additional samples were taken for toxin analysis in plankton and resting cysts in sediments. The results confirm the presence of microalgae associated with toxins in winter, and a higher sensitivity of the relative abundance (RA) than the cellular density, as a parameter of distribution of the microalgae. The maximum RA values were level 2 (low), for Alexandrium catenella and Protoceratium reticulatum; level 1 (rare) for Alexandrium ostenfeldii, Dinophysis acuminata and D. acuta; levels 3 (regular) and 4 (abundant) for Pseudo-nitzschia spp. seriata complex and Pseudo-nitzschia spp. delicatissima complex, respectively. Only PST in plankton and yessotoxins in mo llusks were detected, whereas cyst densities of A. catenella and P. reticulatum in sediments were 4 and 103 cysts mL -1 of wet sediment, respectively. The analyzed parameters showed a bigger inter-annual variability during the winter period, as it has been reported for the summer.

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Integration of meroplankton abundance and hydrographic data was employed to relate the Polygordius exolarvae spatial dynamics with different salinity gradients in order to define the factors that regulate the abundance and spatial distribution along the large estuarine system from southern Chile. The present study aims: i) record the abundance and spatial distribution of Polygordius neustonic exolarvae along of the estuaries with different gradients of salinity located between Guafo Channel, southern Chiloé Island (44º S) to Navarino Island (55º S), Chile; ii) connect this distributional pattern to oceanographic parameters to determine if members of this genus have adapted to euryhaline or stenohaline conditions, and iii) establish a comparison between the abundance of Polygordius and others meroplanktonic taxa collected during CIMAR Cruises 16, 18 and 20 Fjords. Neustonic samples were collected during three oceanographic cruises along southern Chilean fjord/channel systems (~ 1,700 km) with different freshwater supply regimes (CIMAR 16: October/November, 2010, 52º to 55º S; CIMAR 18: June/July, 2012, 44º to 47º S; CIMAR 20: October, 2014, 47º to 50º S), providing evidence to relate the influence of surface salinity on the Polygordius exolarvae spatial distribution of abundance. Polygordius exolarvae (average length=2.9 ± 0.8 mm), the most abundant meroplanktonic taxa within the neustonic community (54.04% of total abundance; 66,228 individuals; N Total =26 stations), was represented at 81% of stations sampled in CIMAR 16 (mean salinity=30.7 psu), showing higher abundance (1,518 ind. x 5 min of horizontal drag) than for other polychaete larvae (10 types) and other meroneustonic taxa; 60% of the abundance of exolarvae during CIMAR 16 was collected around Dawson Island, Magellan Strait. In CIMAR 18 cruise (mean salinity=24.28 psu), abundance of exolarvae was low (3 ind. x 5 min of horizontal drag) and were collected only at 5 stations along the Moraleda Channel (N Total =31 stations); no exolarvae were collected during CIMAR 20 (N total =39 stations) (mean salinity= 23.26 psu). Polygordius exolarvae have narrow haline/thermal requirements during their pelagic life, where sills and island mass effect could produce a restricted and aggregated spatial distribution in some areas of the study zone.

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