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Euphausia superba

Bjørn A Krafft, Ludvig A Krag, Arill Engås, Sigve Nordrum, Inge Bruheim, Bent Herrmann
Antarctic krill (Euphausia superba) is an abundant fishery resource, the harvest levels of which are expected to increase. However, many of the length classes of krill can escape through commonly used commercial trawl mesh sizes. A vital component of the overall management of a fishery is to estimate the total fishing mortality and quantify the mortality rate of individuals that escape from fishing gear. The methods for determining fishing mortality in krill are still poorly developed. We used a covered codend sampling technique followed by onboard observations made in holding tanks to monitor mortality rates of escaped krill...
2016: PloS One
Michael J Polito, Rebecka L Brasso, Wayne Z Trivelpiece, Nina Karnovsky, William P Patterson, Steven D Emslie
Seabirds are ideal model organisms to track mercury (Hg) through marine food webs as they are long-lived, broadly distributed, and are susceptible to biomagnification due to foraging at relatively high trophic levels. However, using these species as biomonitors requires a solid understanding of the degree of species, sexual and age-specific variation in foraging behaviors which act to mediate their dietary exposure to Hg. We combined stomach content analysis along with Hg and stable isotope analyses of blood, feathers and common prey items to help explain inter and intra-specific patterns of dietary Hg exposure across three sympatric Pygoscelis penguin species commonly used as biomonitors of Hg availability in the Antarctic marine ecosystem...
November 2016: Environmental Pollution
Sébastien Descamps, Arnaud Tarroux, Yves Cherel, Karine Delord, Olaf Rune Godø, Akiko Kato, Bjørn A Krafft, Svein-Håkon Lorentsen, Yan Ropert-Coudert, Georg Skaret, Øystein Varpe
Commercial fisheries may impact marine ecosystems and affect populations of predators like seabirds. In the Southern Ocean, there is an extensive fishery for Antarctic krill Euphausia superba that is projected to increase further. Comparing distribution and prey selection of fishing operations versus predators is needed to predict fishery-related impacts on krill-dependent predators. In this context, it is important to consider not only predators breeding near the fishing grounds but also the ones breeding far away and that disperse during the non-breeding season where they may interact with fisheries...
2016: PloS One
Elisa Seyboth, Karina R Groch, Luciano Dalla Rosa, Keith Reid, Paulo A C Flores, Eduardo R Secchi
The reproductive success of southern right whale (Eubalaena australis) depends on body condition and, therefore, on foraging success. This, in turn, might be affected by climatically driven change in the abundance of the species main prey, krill (Euphausia superba), on the feeding grounds. Annual data on southern right whale number of calves were obtained from aerial surveys carried out between 1997 and 2013 in southern Brazil, where the species concentrate during their breeding season. The number of calves recorded each year varied from 7 to 43 ( = 21...
2016: Scientific Reports
Z Mellouk, M Agustina, M Ramirez, K Pena, J Arivalo
AIM: To evaluate the therapeutic effects of dietary krill oil supplementation in modulation of oxidative stress components and DNA oxidative damages marker in cafeteria diet-overfed-rats. MATERIAL AND METHODS: Eighteen aging male Wistar rats were divided into three groups of six each and were exposed for the ensuing 8 weeks to one of the diets: control group (TS) which was submitted to standard chow (330kcal/100g), containing 24% of proteins, 5% of lipids and 70% of carbohydrates...
June 2016: Annales de Cardiologie et D'angéiologie
Alberto Biscontin, Elena Frigato, Gabriele Sales, Gabriella M Mazzotta, Mathias Teschke, Cristiano De Pittà, Simon Jarman, Bettina Meyer, Rodolfo Costa, Cristiano Bertolucci
The Antarctic krill Euphausia superba experiences almost all marine photic environments throughout its life cycle. Antarctic krill eggs hatch in the aphotic zone up to 1000m depth and larvae develop on their way to the ocean surface (development ascent) and are exposed to different quality (wavelength) and quantity (irradiance) of light. Adults show a daily vertical migration pattern, moving downward during the day and upward during the night within the top 200m of the water column. Seawater acts as a potent chromatic filter and animals have evolved different opsin photopigments to perceive photons of specific wavelengths...
May 3, 2016: Marine Genomics
Guanghua Xia, Yanlei Zhao, Zhe Yu, Yingying Tian, Yiming Wang, Shanshan Wang, Jingfeng Wang, Changhu Xue
In the current study, we investigated the improvement of phosphorylated peptides from Antarctic krill Euphausia superba (PP-AKP) on osteoporosis in ovariectomized rats. PP-AKP was supplemented to ovariectomized Sprague-Dawley rats for 90 days. The results showed that PP-AKP treatment remarkably prevented the reduction of bone mass and improved cancellous bone structure and biochemical properties. PP-AKP also significantly decreased serum contents of tartrate-resistant acid phosphatase (TRACP), cathepsin K (Cath-k), matrix metalloproteinases-9 (MMP-9), deoxypyridinoline (DPD), C-terminal telopeptide of collagen I (CTX-1), Ca, and P...
November 4, 2015: Journal of Agricultural and Food Chemistry
Rocío Moreno, Gabriele Stowasser, Rona A R McGill, Stuart Bearhop, Richard A Phillips
Understanding interspecific interactions, and the influences of anthropogenic disturbance and environmental change on communities, are key challenges in ecology. Despite the pressing need to understand these fundamental drivers of community structure and dynamics, only 17% of ecological studies conducted over the past three decades have been at the community level. Here, we assess the trophic structure of the procellariiform community breeding at South Georgia, to identify the factors that determine foraging niches and possible temporal changes...
January 2016: Journal of Animal Ecology
Bruce E Deagle, Cassandra Faux, So Kawaguchi, Bettina Meyer, Simon N Jarman
Antarctic krill (Euphausia superba; hereafter krill) are an incredibly abundant pelagic crustacean which has a wide, but patchy, distribution in the Southern Ocean. Several studies have examined the potential for population genetic structuring in krill, but DNA-based analyses have focused on a limited number of markers and have covered only part of their circum-Antarctic range. We used mitochondrial DNA and restriction site-associated DNA sequencing (RAD-seq) to investigate genetic differences between krill from five sites, including two from East Antarctica...
October 2015: Molecular Ecology
Yanchao Wang, Ruo Wang, Yaoguang Chang, Ying Gao, Zhaojie Li, Changhu Xue
Protein isolate was prepared from defatted Antarctic krill (Euphausia superba) byproducts by 0.1 M NaOH extraction. Maximum yield of krill protein isolate reached 28.66% by precipitation at pH 4.6. Krill protein isolate demonstrated its excellent nutritional values through amino acid composition and in vitro digestibility. Thermal transition of krill protein isolate was determined by differential scanning calorimetry measurement. Extrapolated values of glass transition temperature (Tg) and denaturation temperature (Td) of krill protein isolate were 33...
December 1, 2015: Food Chemistry
Corrie Curtice, David W Johnston, Hugh Ducklow, Nick Gales, Patrick N Halpin, Ari S Friedlaender
BACKGROUND: A population of humpback whales (Megaptera novaeangliae) spends the austral summer feeding on Antarctic krill (Euphausia superba) along the Western Antarctic Peninsula (WAP). These whales acquire their annual energetic needs during an episodic feeding season in high latitude waters that must sustain long-distance migration and fasting on low-latitude breeding grounds. Antarctic krill are broadly distributed along the continental shelf and nearshore waters during the spring and early summer, and move closer to land during late summer and fall, where they overwinter under the protective and nutritional cover of sea ice...
2015: Movement Ecology
Maria João F Martins, Asuncion Lago-Leston, Antonio Anjos, Carlos M Duarte, Susana Agusti, Ester A Serrão, Gareth A Pearson
Euphausia superba is a keystone species in Antarctic food webs. However, the continued decrease in stock density raises concerns over the resilience and adaptive potential of krill to withstand the current rate of environmental change. We undertook a transcriptome-scale approach (454 pyrosequencing) as a baseline for future studies addressing the physiological response of krill to short-term food shortage and natural UV-B stress. The final assembly resulted in a total of 26,415 contigs, 39.8% of which were putatively annotated...
October 2015: Marine Genomics
Kévin Cascella, Didier Jollivet, Claire Papot, Nelly Léger, Erwan Corre, Juliette Ravaux, Melody S Clark, Jean-Yves Toullec
BACKGROUND: A comparative thermal tolerance study was undertaken on two sister species of Euphausiids (Antarctic krills) Euphausia superba and Euphausia crystallorophias. Both are essential components of the Southern Ocean ecosystem, but occupy distinct environmental geographical locations with slightly different temperature regimes. They therefore provide a useful model system for the investigation of adaptations to thermal tolerance. METHODOLOGY/PRINCIPAL FINDING: Initial CTmax studies showed that E...
2015: PloS One
B Meyer, P Martini, A Biscontin, C De Pittà, C Romualdi, M Teschke, S Frickenhaus, L Harms, U Freier, S Jarman, S Kawaguchi
The Antarctic krill, Euphausia superba, has a key position in the Southern Ocean food web by serving as direct link between primary producers and apex predators. The south-west Atlantic sector of the Southern Ocean, where the majority of the krill population is located, is experiencing one of the most profound environmental changes worldwide. Up to now, we have only cursory information about krill's genomic plasticity to cope with the ongoing environmental changes induced by anthropogenic CO2 emission. The genome of krill is not yet available due to its large size (about 48 Gbp)...
November 2015: Molecular Ecology Resources
Stéphane Thanassekos, Martin J Cox, Keith Reid
Antarctic krill (Euphausia superba; herein krill) is monitored as part of an on-going fisheries observer program that collects length-frequency data. A krill feedback management programme is currently being developed, and as part of this development, the utility of data-derived indices describing population level processes is being assessed. To date, however, little work has been carried out on the selection of optimum recruitment indices and it has not been possible to assess the performance of length-based recruitment indices across a range of recruitment variability...
2014: PloS One
Yanchao Wang, Shanshan Wang, Jingfeng Wang, Changhu Xue, Yaoguang Chang, Yong Xue
Antarctic krill (Euphausia superba) protein serves as a novel sustainable protein source for human. Krill protein isolate was phosphorylated by the dry-heating method with sodium pyrophosphate. Phosphorylated peptides from Antarctic krill (PP-AKP) were obtained from phosphorylated protein through tryptic hydrolysis. Two types of phosphate bonds were introduced by phosphorylation, i.e. PO and PO bonds. The anti-osteoporotic activities of PP-AKP at two doses (400 and 800mg/kg body weight) were investigated with an osteoporotic rat model, which was established with bilateral ovariectomy surgery...
June 2015: Peptides
Jianan Sun, Feifei Kan, Pei Liu, Shuai He, Haijin Mou, Changhu Xue, Xiangzhao Mao
Twelve kinds of strains were isolated from deep-sea mud which can use Antarctic krill powder as the sole carbon/nitrogen source. These strains were identified by 16s rDNA sequence analysis and grouped into eight different genera, including Bacillus, Shewanella, Psychrobacter, Klebsiella, Macrococcus, Aeromonas, Acinetobacter, and Saccharomyces. After fermentation of Antarctic krill powder using these strains, bioactive compounds including total phenolics, free amino acids, and enzyme activities were investigated...
February 2015: Applied Biochemistry and Biotechnology
Nicola Bellini, Martin J Cox, Danielle J Harper, Sebastian R Stott, Praveen C Ashok, Kishan Dholakia, So Kawaguchi, Robert King, Tammy Horton, Christian T A Brown
Many small open ocean animals, such as Antarctic krill, are an important part of marine ecosystems. To discover what will happen to animals such as krill in a changing ocean, experiments are run in aquaria where conditions can be controlled to simulate water characteristics predicted to occur in the future. The response of individual animals to changing water conditions can be hard to observe, and with current observation techniques it is very difficult to follow the progress of an individual animal through its life...
2014: PloS One
Wenfang Gao, Daicheng Liu, Shupeng Su
1-Octacosanol is a straight-chain aliphatic 28-carbon fatty alcohol with well-known anti-fatigue function. In this study, 1-octacosanol was extracted from Antarctic krill for the first time. Separation of 1-octacosanol was achieved using high-performance thin-layer chromatography (TLC) with a mobile phase consisting of petroleum ether/ethyl acetate/toluene (4 : 1 : 0.05, v/v/v) on precoated silica gel GF254 high-performance TLC plates. The separated 1-octacosanol was quantified using spectrodensitometry with distilled water/bromothymol blue/sodium hydroxide (100 : 0...
May 2015: Journal of Chromatographic Science
Ludvig A Krag, Bent Herrmann, Svein A Iversen, Arill Engås, Sigve Nordrum, Bjørn A Krafft
Trawlers involved in the Antarctic krill (Euphausia superba) fishery use different trawl designs, and very little is known about the size selectivity of the various gears. Size selectivity quantifies a given trawl's ability to catch different sizes of a harvested entity, and this information is crucial for the management of a sustainable fishery. We established a morphological description of krill and used it in a mathematical model (FISHSELECT) to predict the selective potential of diamond meshes measuring 5-40 mm with mesh opening angles (oa) ranging from 10 to 90°...
2014: PloS One
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