Lithodidae

Las centollas están entre los artrópodos más grandes del mundo, con ejemplares de tamaño extremo de más de 1,5 m de apertura entre patas y más de 10 kg de peso. Su gran tamaño les valió, entre varios apelativos, el nombre vulgar de King Crab en inglés, o crabe royal en francés, por ejemplo. Sin embargo el significado del género Lithodes (del griego lithos=roca, y eidos=forma)que le da nombre a la familia significa parecido a una roca o de naturaleza o estructura rocosa. Como son especies de interés comercial nombres vernáculos idénticos fueron usados frecuentemente para denominar diferentes especies. Varias de éstas se encuentran en aguas de plataformas continentales en altas concentraciones que han sustentado pesquerías importantes y muy rentables. Constituyen un producto muy apreciado en la gastronomía mundial por su alto rendimiento en carne, delicado sabor y textura. Quizás el programa televisivo Pesca Mortal haya coronado su popularidad a nivel masivo, sobre todo por las condiciones meteorológicas extremas en el que se desarrolla su pesca.Fil: Lovrich, Gustavo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin

Reproducción y crecimiento del centollón, Paralomis granulosa (Crustácea, Anomura, Lithodidae) en el Canal Beagle

Fil:Lovrich, Gustavo Alejandro. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Distribution and population structure of the crab Halicarcinus planatus (Brachyura, Hymenosomatidae) in the Beagle Channel, Tierra del Fuego

El cangrejo Halicarcinus planatus es el único himenosomátido que habita el extremo austral de Sudamérica, con una distribución subantártica, incluyendo las islas periantárticas y Nueva Zelanda. En este trabajo, se presenta información sobre la abundancia y estructura poblacional de H. planatus en el intermareal de Bahía Brown, Canal Beagle, Tierra del Fuego durante un año. Además, se muestran las variaciones en la estructura poblacional en otras playas y ambientes del canal. A diferencia de los machos, la densidad de hembras mostró fluctuaciones mensuales en el intermareal de Bahía Brown y fue mayor durante los meses de verano. Las altas densidades de H. planatus podrían relacionarse con la baja mortalidad de estadios larvales y las características oceanográficas de la bahía, probablemente aumentado por la presencia de bancos y cuerdas de cultivo de mejillones, sustratos donde ocurriría el asentamiento de H. planatus. La proporción de sexos poblacional estuvo sesgada hacia las hembras solo en verano, mientras que la proporción sexual operativa se sesgó hacia los machos durante casi todo el período estudiado, sugiriendo una fuerte competencia entre machos por el apareamiento. A su vez, los machos solo estuvieron presentes en el intermareal de Bahía Brown y en los grampones de Macrocystis pyrifera pero no se encontraron en el resto de los intermareales estudiados, probablemente relacionado con la ausencia de refugio en el submareal de Bahía Brown. El reclutamiento existiría en dos períodos diferentes, verano (enero-febrero) y otoño-invierno (mayo-junio), que se corresponde con las dos cohortes larvales de H. planatus presentes en el Canal Beagle.The crab Halicarcinus planatus is the only hymenosomatid that inhabits the southern tip of South America and has a sub-Antarctic distribution, including the peri-Antarctic islands and New Zealand. In this paper, we report the abundance and population structure of H. planatus for a year in the intertidal zone of Bahía Brown, Beagle Channel, Tierra del Fuego. Moreover, we show variations in the population structure in other beaches and environments of the channel. In contrast with males, female density showed monthly variations and was higher during austral summer months. High densities of H. planatus could be related with low mortality during the larval stage and oceanographic features of Bahía Brown, probably enhanced by the presence of both culture and mussel beds, substrates where settlement would occur. The populational sex ratio was biased towards females only in summer, while the operational sex ratio was biased towards males during all periods studied, suggesting strong competition among males for mating. In turn, males were present only in the intertidal zone of Bahía Brown and Macrocystis pyrifera but were absent in the other studied intertidal areas.This is perhaps related to the lack of shelter in the subtidal zone of Bahía Brown. Recruitment occurs in two different periods, summer (January-February) and autumn-winter (May-June), which corresponds with the two larval cohorts of H. planatus in the Beagle Channel.Fil: Diez, Mariano Javier. 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: Lovrich, Gustavo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin

Nueva localidad para Notochthamalus scabrosus (Crustacea, Cirripedia): Bahía Lapataia, Canal Beagle, Tierra del Fuego, Argentina

Notochthamalus scabrosus (Darwin 1854) is commonly attached to littoral rocks and shells, often associated with Notobalanus flosculus (Darwin 1854), and sometimes with Chthamalus cirratus (Darwin 1851). Notochthamalus scabrosus was previously reported from Peru to Tierra del Fuego and Islas Malvinas / Falkland Islands by Darwin (1851). Moreover, the review of South American barnacle distribution by Young (1995) suggested that the temperate zone of the Southwestern Atlantic, occurring between 35ºS and the southern tip of South America (56ºS), had a barnacle fauna similar to that of the Southeastern Pacific (coasts of Chile and Peru), with N. scabrosus occurring at both zones. Particularly in the Beagle Channel, N. scabrous is the dominant species in the upper zone of the rocky intertidal. The Beagle Channel is located at the southernmost tip of South America (ca. 55º S; 68º W) and is an ancient glacial valley of about 210 km length and 5 km width, with different basins. The Beagle Channel has fjord estuarine features with salinities lower than the surrounding oceanic water masses due to the discharge of glaciers and rivers (Balestrini et al. 1998; Isla et al. 1999). One of these subsystems is the estuarine complex of Lago Roca-Bahía Lapataia, a palaeo-fjord currently constituted by a lake discharging freshwater to the channel via the Ovando River (Isla et al. 1999; Fig. 1). Zaixso et al. (1978) described the rocky intertidal flora and fauna from 11 localities at the Beagle Channel. N. scabrosus was reported by the authors from three localities: Bahía Ensenada (Ensenada Zaratiegui) (54º 50? S; 68º 28 W), Punta Jones (54º 49? S; 68º 13 W) and Bahía Ushuaia (54º 49? S; 68º 19 W). With regard to Bahía Lapataia, Zaixso et al. (1978) mentioned that this species was absent there, likely as a consequence of the low salinity characterizing the zone. Authors reported the presence of Elminius kingii (Gray 1831) as the only barnacle species for this location. In the present study we report for the first time the presence of N. scabrosus in the upper zone of the rocky intertidal of the western coast of Bahía Lapataia (54º 51.54? S, 68º 33.87? W), Tierra del Fuego (Fig. 1). Specimens of N. scabrosus were found along with Elminius kingii (Fig. 2). On September 25th, 2008 photographs and samples of both species were taken. The samples were collected for accurate identification after dissection. Especially during spring and summer, Ensenada Zaratiegui and Bahía Lapataia have very variable and lower salinity than other sites of the Beagle Channel, which in turn are less influenced by freshwater discharges (Table 1). N. scabrous is clearly a euryhaline species since specimens can tolerate a range of salinities of 15 31 ups. Although there are no specific studies on salinity tolerance of this species, the genus Chthamalus is known to be euryhaline (e.g. Crisp & Costlow 1963, López & González 2003, Farrapeira 2008). Roughgarden et al. (1988) and Alexander & Roughgarden (1996) have suggested that the ecology of a rocky intertidal community at a site would be governed by adult-adult interactions within the site, or by limitations to the supply of larvae reaching the site, the latter being determined by the regional pattern of circulation and physical oceanography in the coastal waters. These characteristics would explain the variation of timing of recruitment at the coast and the likely reason that it occurs in discrete pulses. We propose that the establishment of N. scabrosus in Bahía Lapataia could be a consequence of local hydrological events, namely coastal currents, wind direction and intensity and availability of larvae in the plankton rather than by the low saline waters characterizing the zone, and these events would explain the discontinuous scheme of distribution of N. scabrosus along the coast of the Beagle Channel. This channel is a particular environment because of its fjord features and its semi-closed condition (Antezana 1999). For example, the freshwater input may change the environmental conditions at a geographical micro-scale. In some western coves the ice input from glaciers may produce the typical coastal disturbance so that the intertidal community may be locally impoverished or absent (c.f. Mutschke & Gorny 1999; Barnes 2005). Hence, the presence of certain species at different sites with both different freshwater input and coastal orientation and therefore differentially affected by winds and currents may be indicators of specific hydrological processes acting on the community structure and/or diversity.Fil: Curelovich, Jessica Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Belgrano. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Lovrich, Gustavo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Calcagno, Javier Ángel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Belgrano. Facultad de Ciencias Exactas y Naturales; Argentin

Larval development of the subantarctic king crabs Lithodes santolla and Paralomis granulosa reared in the laboratory

The larval development and survival in the two subantarctic lithodid crabs Lithodes santolla (Jaquinot) and Paralomis granulosa (Molina) from the Argentine Beagle Channel were studied in laboratory cultures. In L. santolla, larval development lasted about 70 days, passing through three zoeal stages and the megalopa stage, with a duration of approximately 4, 7, 11 and 48 days, respectively. The larval development in P. granulosa is more abbreviated, comprising only two zoeal stages and the megalopa stage, with 6, 11 and 43 days' duration, respectively. In both species, we tested for effects of presence versus absence of food (Artemia nauplii) on larval development duration and survival rate. In P. granulosa, we also studied effects of different rearing conditions, such as individual versus mass cultures, as well as aerated versus unaerated cultures. No differences in larval development duration and survival were observed between animals subjected to those different rearing conditions. The lack of response to the presence or absence of potential food confirms, in both species, a complete lecithotrophic mode of larval development. Since lithodid crabs are of high economic importance in the artisanal fishery in the southernmost parts of South America, the knowledge of optimal rearing conditions for lithodid larvae is essential for future attempts at repopulating the collapsing natural stocks off Tierra del Fuego.Fil: Calcagno, Javier Ángel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Anger, K.. Alfred Wegener Institute for Polar and Marine Research; AlemaniaFil: Lovrich, Gustavo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Thatje, S.. Alfred Wegener Institute for Polar and Marine Research; AlemaniaFil: Kaffenberger, A.. Alfred Wegener Institute for Polar and Marine Research; Alemani

Pole to pole: the deep-sea king crab Lithodes couesi (Decapoda: Lithodidae) in the Burdwood Bank, Southwestern Atlantic Ocean

In recent years, remote exploration around the Scotia Arc and waters off the Antarctic Peninsula yielded new records of Lithodidae suggesting our knowledge on their distribution is biased by our ability to sample areas with difficult access. In the present study, we used molecular methods to identify and report the occurrence of the deep-sea king crab Lithodes couesi, so far reported as a North Pacific lithodid, in the marine protected area (MPA) Namuncurá/Burdwood Bank II, Southwestern Atlantic Ocean; more than 10,000 km away from its known distribution. Our finding suggests that the distributions of deep-water lithodid species are more extensive than they have been previously thought. We emphasize the need for a worldwide key to identify lithodid species, and prompt to barcoding specimens, at least those from poorly known species or remote locations, in order to corroborate their specific status. Finally, our study stresses the importance of MPAs in the conservation of biodiversity, as well as the processes involved in its evolution.Fil: Pérez Barros, Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y Diagnóstico. Departamento de Ciencias Naturales y Antropológicas; ArgentinaFil: Albano, Mariano Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Diez, Mariano Javier. 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; Argentin

Energy reserves mobilization: Strategies of three decapod species

In food deprivation assays, several different responses have been observed in crustaceans. However, studying energy reserves utilization among more than one species during the same starvation period has not yet been performed, particularly to discern whether the responses are due to intrinsic and/or environmental factors. We hypothesize that decapod species with similar feeding habits have the same strategies in the use of energetic reserves during starvation, even though they inhabit different environments. The aim of this study was to compare the energy reserves mobilization of three decapods species (Cherax quadricarinatus, Palaemon argentinus and Munida gregaria) with similar feeding habits, exposed to similar food deprivation conditions. The crayfish, shrimp and squat-lobster were experimentally kept at continuous feeding or continuous starvation throughout 15 days. Every 3rd day, the midgut gland index (MGI), and the glycogen, lipid and protein contents were measured in the midgut gland (MG) and pleon muscle. Palaemon argentinus mobilized more reserves during starvation, followed by C. quadricarinatus, and the last M. gregaria. The starved shrimps presented low MGI, whereas MG showed a reduction in glycogen (from day 6 to 15), lipid (from day 3 to 15), and protein levels (at day 9 and 15) while in their muscle, lipid reserves decreased at days 3 and 6. In C. quadricarinatus, the most affected parameters in the MG were MGI, glycogen (from day 6 to 15), and lipids (at day 12 and 15). In the MG of M. gregaria only the glycogen was reduced during fasting from 3 to 15 days. Even though the three studied species have similar feeding habitats, we found that their energetic profile utilization is different and it could be explained by the habitat, life span, temperature, organ/tissue, and metabolism of the species. Our results may be useful to understand the several different responses of crustaceans during starvation.Fil: Sacristán, Hernán Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Rodriguez, Yamila Eliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Pereira, Nair de Los Angeles. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Lopez, Laura Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Lovrich, Gustavo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Fernandez Gimenez, Analia Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin

Effects of starvation and stocking density on the physiology of the male of the southern king crab Lithodes santolla

The southern king crab (SKC)Lithodes santolla is an important commercial species in southern South America. There is a greater need for availability of fresh and live crabs during the season of highest demand in summer (mainly December and January). Thus, this study aimed to determine the effects of starvation and stocking densities on the physiological status of male SKC to know whether SKC can be stocked after they are fished. To assess the effects of starvation, crabs were assigned to two experimental groups: the Laboratory group (in which crabs were either fed daily (controls), fed every 15 days, or starved and the Sea group (in which crabs were either fed every 15 days or starved). Starved crabs showed a very slight mass reduction (<5%), glycogen depletion from the midgut gland (when kept at sea), lipid peroxidation reduction in both the muscle and the midgut gland, and micro-structural alterations of the midgut gland. Starved crabs were then analyzed at three stocking density levels: low (35 crabs m−3), medium (69 crabs m−3), and high (115 crabs m−3)for 30 days. In this experiment, we found, at all densities, a decreased weight of the midgut gland, a low condition index, decreased lipase activity, glycogen reduction, increased protein reserves, and lipid peroxidation reduction, and decreased lipid levels at low and medium densities. The muscle showed, at all densities, an increased protein oxidation and a decrease in the RNA:DNA ratio. Our results suggest that SKC can tolerate relatively high stocking densities, have low mortality, and are able to endure 60 days of food deprivation without lowering their flesh yield. This would allow marketing crabs alive off-season.Fil: Sacristán, Hernán Javier. 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: Fernandez Gimenez, Analia Veronica. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Lovrich, Gustavo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin

Ascidian distribution provides new insights to help define the biogeographic provinces in the South American Region

The validity and size of the biogeographic Magellan Province of marine organisms have been the focus of discussion of many authors. The distribution of fish and other organisms has revealed a lack of homogeneity in the area, which has also been interpreted as comprising four different Provinces: Southern Chile (SCH), Tierra del Fuego (TDF), Southern Argentina (SAR), and the Malvinas/Falkland Islands (MAI). For the first time, we assess the ascidian fauna of this region to determine if the distribution of benthic sessile filter feeders corresponds to these biogeographic provinces. Ascidian species richness and percentages of endemism for these four areas were estimated using data from the literature and new sampling. Biogeographic affinities among SCH, TDF, SAR, and MAI were also calculated. The species Pyura pilosa, Molgula malvinensis, and Molgula manhattensis, the latter frequently considered as invasive, were found for the first time on the TDF shelf. The highest ascidian species richness was found in TDF (70 species), while the percentages of endemism greater than 10% (the minimum to qualify an area as a province) were found in TDF (15.7%) and SCH (11.1%). SAR and MAI showed the lowest percentages of endemism and the strongest affinity. Based on percentages of endemism, faunal affinities, and differences among the four provinces, we propose a separation of the South American Region into three Provinces: SCH, TDF, and SAR/MAI. Continued sampling of ascidians is considered to be particularly important, given the potential spread of invasive species throughout this region.Fil: Taverna, Anabela Jesús. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Lagger, Cristian Fabian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Maggioni, Tamara. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Reyna, Paola Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Lovrich, Gustavo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Tatian, Marcos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentin

Defensas antioxidantes y peroxidación de lípidos en dos especies de Lithodes del Atlántico Sur durante el verano

En el sur de Sudamérica Lithodes santolla y L. confundens representan las especies de centollas más apreciadas, debido a sus altos rendimientos y aceptación en los mercados. Desde un punto de vista fisiológico, las especies reactivas del oxígeno (ROS) son continuamente producidas como productos de la respiración celular. Estos ROS se transforman en metabolitos menos tóxicos por medio de enzimas antioxidantes. El objetivo fue determinar en Lithodes santolla (del Golfo San Jorge) y L. confundens (de la costa atlántica de Tierra del Fuego) el nivel de base de la actividad enzimática antioxidante y los niveles de peroxidación de lípidos. Las enzimas catalasa (CAT) y glutatión-S-transferasa (GST) y la peroxidación de lípidos se midieron en branquias, músculo y hepatopáncreas. Ambas especies mostraron actividad enzimática antioxidante, mientras que las branquias presentaron la mayor actividad enzimática de CAT. La actividad de CAT y GST fue mayor en L. confundens en el músculo y branquias respectivamente, comparado con L. santolla; mientras que la peroxidación de lípidos fue menor en ambos órganos. Estas diferencias entre ambas especies sugieren que L. confundens sería más eficiente ante situaciones de estrés oxidativo, debido probablemente a los periodos de anoxia que experimenta durante las bajas mareas de primavera. Además, estas diferencias podrían ser atribuidas a características intrínsecas de adaptación de cada especie de centolla y/o a condiciones ambientales de cada área de estudio en particular. Parámetros como CAT, GST y peroxidación de lípidos podrían proponerse como biomarcadores de estrés oxidativo en Lithodes santolla y L. confundens.In Southern South America Lithodes santolla and L. confundens are the most valuable king crabs species, specially due to their high yields and their high acceptance in the markets. From a physiological point of view, reactive oxygen species (ROS) are continuously produced as by-products of cell respiration. These ROS are transformed into less toxic metabolites by antioxidant enzymes. The aim of the present study was to determine in Lithodes santolla (from San Jorge Gulf) and L. confundens (from Atlantic coast of Tierra del Fuego) the baseline status of both antioxidant enzyme activity and lipid peroxidation levels. Activities of catalase (CAT), glutathione-S-transferase (GST), as well as lipid peroxidation were measured in the muscle, gills and hepatopancreas. Both species showed antioxidant enzyme activities, and the gills were the organs with the highest CAT enzyme activities. CAT and GST activities were higher in muscle and gills, respectively, in L. confundens compared with L. santolla, whereas lipid peroxidation was low in both organs. These differences between both species suggest that L. confundens is more capable to afford oxidative stress than L. santolla, which may be a response to the common occurrence of L. confundens at the intertidal during the spring low tides. Differences in the analysed parameters could be attributed to intrinsic adaptation features of each king crab species and/or to environmental conditions of each particular study area. Furthermore, our results showed that parameters as CAT, GST and lipid peroxidation could be proposed as biomarkers of oxidative stress in Lithodes santolla and L. confundens.Fil: Romero, Maria Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina;Fil: Schvezov, Natasha. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina;Fil: Sotelano, María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina;Fil: Diez, Mariano Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina;Fil: Florentin, Olga Viviana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina;Fil: Tapella, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina;Fil: Lovrich, Gustavo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina