Two new cryptic and sympatric species of the king crab parasite Briarosaccus (Cirripedia: Rhizocephala) in the North Pacific

Rhizocephalan barnacles have been reported to parasitize a wide range of king crab species (Lithodidae). So far all these parasites have been assigned to a single species, Briarosaccus callosus Boschma, 1930, which is assumed to have a global distribution. Here we investigate Briarosaccus specimens from three different king crab hosts from the fjord systems of Southeastern Alaska: Lithodes aequispinus Benedict, 1895, Paralithodes camtschaticus (Tilesius, 1815), and Paralithodes platypus (Brandt, 1850). Using molecular markers and by morphological comparison we show that Briarosaccus specimens from these three commercial exploited king crabs are in fact morphologically distinct from B. callosus, and further represent two separate species which we describe. The two new species, Briarosaccus auratum n. sp. and B. regalis n. sp., are cryptic by morphological means and were identified as distinct species by the use of genetic markers (COI and 16S). They occur sympatrically, yet no overlap in king crab hosts occurs, with B. auratum n. sp. only found on L. aequispinus, and B. regalis n. sp. as parasite of the two Paralithodes hosts.publishedVersio

Climate Change and invasibility of the Antarctic benthos

Benthic communities living in shallow-shelf habitats in Antarctica (<100-m depth) are archaic in their structure and function. Modern predators, including fast-moving, durophagous (skeleton-crushing) bony fish, sharks, and crabs, are rare or absent; slow-moving invertebrates are the top predators; and epifaunal suspension feeders dominate many soft substratum communities. Cooling temperatures beginning in the late Eocene excluded durophagous predators, ultimately resulting in the endemic living fauna and its unique food-web structure. Although the Southern Ocean is oceanographically isolated, the barriers to biological invasion are primarily physiological rather than geographic. Cold temperatures impose limits to performance that exclude modern predators. Global warming is now removing those physiological barriers, and crabs are reinvading Antarctica. As sea temperatures continue to rise, the invasion of durophagous predators will modernize the shelf benthos and erode the indigenous character of marine life in Antarctica

Recovery at Morvin: SERPENT final report

Recovery from disturbance is poorly understood in deep water, but the extent of anthropogenic impacts is becoming increasingly well documented. We used Remotely Operated Vehicles (ROV) to visually assess the change in benthic habitat after exploratory hydrocarbon drilling disturbance around the Morvin well located at 380m depth in the Norwegian Sea.An ROV, launched directly from the rig drilling the well in 2006 was used to carry out video transects around the well before drilling and immediately after. On a return to the site three years after disturbance a larger survey was conducted with a ship-launched ROV in 2009. Transects were repeated at the disturbed area and random background transects were taken. Visible drill cuttings were mapped for each survey, and positions and counts of epibenthic invertebrate megafauna were determined, revealing a fauna dominated by Cnidaria (45% of total observations) and Porifera (33%).Immediately after disturbance a visible cuttings pile extended to over 100m from the well and megafaunal density was significantly reduced (0.07 individuals m-2) in comparison to pre-drill data (0.23 ind. m-2). Three years later the visible extent of the cuttings pile had reduced in size, reaching 60m from the well and considerably less in some headings. In comparison to background transects (0.21 ind. m-2), megafaunal density was significantly reduced on the remaining cuttings (0.04m-2), but beyond the visible disturbance there was no significant difference (0.15m-2). The investigation at this site shows a return to background densities of megafaunal organisms over a large extent of the area previously disturbed. However a central area, where the initial cuttings pile was deepest, demonstrated reduced sessile megafaunal density which persisted three years after disturbance. Elevated Barium concentration and reduced sediment grain size suggests persistence of disturbance beyond the remaining visibly impacted area which may result in changes to the infaunal communities undetectable by ROV video survey

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

Las centollas colonizan la Antartida

Es conocido que en Antartida no viven cangrejos. El hallazgo en los ultimo años de centolla podria estar anunciando la futura conquista de la Antartida por los cangrejos

Diet composition of cod (Gadus morhua): small-scale differences in a sub-arctic fjord

Masteroppgave i marin økologi - Universitetet i Nordland, 201

Hábitos alimentarios del centollón Paralomis granulosa (lithodidae) en el Canal del Beagle, Tierra del Fuego, Argentina

Stomach contents of 282 false southern king crabs (Paralomis granulosa), between 10 to 90 mm CL from the Beagle Channel (Golondrina Bay and Roca Mora), Argentina, were examined by the frequency of occurrence method of analysis and by a food index. Roca Mora is an area where juveniles ( 60 mm CL) are common; in this last area sexual segregation was also observed. The principal food groups for crabs of Golondrina Bay were algae, molluscs, crustaceans, bryozoans and foraminiferans; for crabs from Roca Mora the natural diet consisted of three major food groups: hydrozoans, echinoderms and foraminiferans. The relative frequency of different prey groups varied in relation to the size, season and sex. There were no significant differences in the quantity of food consumed by sexes in both areas. Generally small crabs ( 50 mm CL). Juveniles consumed a greater amount of food during winter and spring. In summer (moulting period), juveniles had the highest vacuity index. Adults consumed minor amounts of food during autumn, before the spawning-moulting-mating period when the vacuity index was higher (spring).Se analizaron 282 contenidos estomacales de centollón (Paralomis granulosa), comprendidos entre 10 mm y 90 mm de largo de caparazón (LC), provenientes del Canal del Beagle (Bahía Golondrina y Roca Mora), Argentina. El análisis se basó en la frecuencia de presencia de los grupos que conforman la dieta y el peso relativo del contenido estomacal. Roca Mora es un área dominada por juveniles ( 60 mm LC). En esta última se observó segregación sexual. Los principales grupos que conforman la dieta de los individuos de Bahía Golondrina fueron algas, moluscos, crustáceos, briozoos y foraminíferos; mientras que para los de Roca Mora la dieta natural comprende tres grupos principales: hidrozoos, equinodermos y foraminíferos. Las frecuencias relativas de los diferentes grupos variaron en relación a la talla, época de muestreo y sexo. No se detectaron diferencias significativas en la cantidad de alimento consumido en relación al sexo en ambas áreas. Generalmente los cangrejos pequeños ( 50 mm LC). Los juveniles consumieron mayor cantidad de alimento durante el invierno y primavera. Durante el verano (período de muda) se determinó el mayor índice de vacuidad. Los adultos consumieron mayores cantidades de alimento durante el verano, después del período de desove-muda-apareamiento cuando el índice de vacuidad fue mayor (primavera)

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

Spatial variability in size at maturity and reproductive timing of golden king crab (Lithodes aequispinus) in Southeast Alaska

Thesis (M.S.) University of Alaska Fairbanks, 2016Many crab fisheries around the world are managed by size, sex and season regulations, where male crabs are given at least one opportunity to reproduce before being harvested. Therefore, to set minimum legal size and fishing season for harvest, information on size at maturity and reproductive timing is needed. Lithodes aequispinus has supported a commercial fishery in Southeast Alaska since 1972, with an average annual harvest of 207 t. The current legal size and season for harvest are based L. aequispinus growth and maturity information from other parts of the range and limited information on reproduction. Additionally, evidence suggests that these life history parameters can vary spatially. Therefore, I investigated size at maturity, reproductive timing, and variation in harvest from the commercial fishery for L. aequispinus. I compared size at maturity estimates (males and females), mean spine contribution to legal size male crabs, and depth and bottom temperature among seven management areas in Southeast Alaska (Lynn Canal, Icy Strait, North Stephens Passage, Frederick Sound, Mid-Chatham Strait, Lower Chatham Strait, and Clarence Strait) and investigated reproductive timing of mature females in Frederick Sound. Male size of maturity estimates varied spatially, with an increasing trend with latitude and significant differences occurred among the majority of management areas. Female maturity estimates varied significantly among all areas, but showed no latitudinal pattern. The latitudinal pattern for size at male maturity in Southeast Alaska differed from published values in other parts of the range (Japan, Russia, the Bering Sea and from the Aleutian Islands to Canada), where size at maturity decreased with increasing latitude. When I investigated the ability of environmental factors to explain the patterns in Southeast Alaska, depth and temperature were not found to influence the spatial variation in male maturity estimates. Depth varied by management area, and males and females were distributed at similar depths. Temperature varied less than 1.0 °C among management areas, and monthly temperature measured at a mooring in the Gulf of Alaska also varied by less than 1.0 °C throughout the year at depths where L. aequispinus are found (250 m). Mean spine contribution to legal size varied spatially but did not influence calculated legal size. Reproductive timing was determined for eyed embryos, with projected hatching of embryos occurring from April to November, indicating that a distinct reproductive season does not exist. Management implications from this research are that the current legal size (177.8 mm/7.0 in carapace width (CW)) does not allow male crab to reproduce at least once before being harvested for all management areas. If legal size is increased to 196.5 mm/7.7 in CW, a higher proportion of male crab could reproduce at least once before being harvested. This size change could have negative economic impact to the commercial fishery with potential harvest lost in areas with smaller sizes at maturity. This study shows the importance of re-examining legal size and season based on an improved understanding of how life history characteristics change over space and the resulting implications for improved fisheries management