Krill

Lipids are key biochemicals that form both cell membranes and energy stores. Lipids are of particular importance in energy poor environments where animals require stores to survive long periods of food shortage. In the Antarctic, food availability is dominated by extreme seasonal shifts in the environment and energy rich food is scarce for a substantial period of time each year. Antarctic krill (Euphausia superba) have adapted to have large lipid stores (over a third of their dry weight) during winter for this reason. Krill are a key species in the Antarctic environment; their biomass links lower and higher trophic levels and forms the main energy conduit for the system. Krill feed on diatoms, dinoflagellates and other algal species year-round, resulting in high omega-3 polyunsaturated fatty acids which are essential for krill health, growth and reproduction. Krill-derived omega-3 containing products (particularly eicosapentacnoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3)) are sold as nutraceuticals for human consumption. Krill oil tablets (sold as an omega-3 supplement) are now the fastest growing nutraceutical globally.
Understanding the krill life cycle is hampered by the restricted nature of scientific sampling. Knowledge of krill diet and krill lipid dynamics is lacking for the Indian and Pacific Ocean sectors, as most studies have focused on the South Atlantic Ocean sector where the krill fishery is based. Most scientific research voyages are conducted during summer months and all scientific studies are restricted in their spatial and temporal scale. Information on krill recruitment and reproduction in the Indian and Pacific Ocean sectors is also not as developed as in the South Atlantic, where fishery-derived samples are also available.
A major gap in current ecosystem models is the link between environmental drivers (such as upwelling of nutrients, sea surface temperature and height, sea ice extent and thickness and salinity) and their impact on primary production and therefore food availability during extreme seasonal shifts in Antarctica. One way of measuring these environmental drivers is through remote-sensing via satellite, which can gather data over large geographic areas and over long timeframes. Satellite-derived data for biological and ecological measures is still developing as a tool for oceanographers and other end users. However, one area of growing importance is in the use of ocean colour data which can be converted into chlorophyll a concentrations (a proxy for primary production) via a standard algorithm. By linking the GPS locations of commercial krill harvesting, and therefore krill swarms, to environmental data obtained through remote-sensing from the same date, the relationship between the environment krill live in and their biochemical composition can be examined in ways not previously explored.
My study used samples collected by a member of the krill fishery, Aker BioMarine, over a continuous three-year period in the South Atlantic Ocean to look at the seasonal and interannual trends in krill total lipids and lipid classes (such as those used for energy storage and the structure and function of cells). This dataset is unprecedented in its seasonal and spatial coverage in the South Atlantic Ocean. This study has been able to establish the sinusoidal shape of the seasonal and interannual trend in krill total lipids and its associated lipid classes. No samples from the fishery were available from other sectors. These South Atlantic Ocean krill samples were contrasted to krill samples collected from scientific expeditions in the other two ocean basins surrounding Antarctica (Pacific and Indian Oceans). Krill diet was investigated at a regional scale during the crucial late-summer spawning period. Results from my study revealed that krill diet varies between ocean basins, with Indian Ocean krill showing a distinctly different diet to Pacific and Atlantic Ocean krill, during the late-summer.
The fishery-derived samples were also related back to environmental data collected via satellite, for both chlorophyll a and sea surface temperature, to investigate if environmental drivers influenced krill lipid biochemistry. This study showed that both sea surface temperature and chlorophyll a concentrations (derived from ocean colour data) can be related to krill lipid and fatty acid dynamics. Krill lipid composition and content were shown to be correlated to these environmental factors through simple models. The combination of results from this study will help fill the data gaps in ecosystem models and enable better determination of krill diet, recruitment and reproduction in all ocean basins surrounding Antarctica.  These advances in krill knowledge will help improve fishery management policies.

ABSTRACT: An experimental method to estimate the relative swimming capacity of pelagic crustaceans is proposed. Swimming capacity measured as propulsive force can be estimated by attaching the animal to a virtually friction free rotational displacement transducer with an arm allowing only forward and backward movements. The method also allows determination of beat rates of the pleopod cycle.

Antarctic krill (Euphausia superba) are a key component of the Antarctic food web with considerable lipid reserves that are vital for their health and higher predator survival. Krill lipids are primarily derived from their diet of plankton, in particular diatoms and flagellates. Few attempts have been made to link the spatial and temporal variations in krill lipids to those in their food supply. Remotely-sensed environmental parameters provide large-scale information on the potential availability of krill food, although relating this to physiological and biochemical differences has only been performed on small scales and with limited samples. Our study utilised remotely-sensed data (chlorophyll a and sea surface temperature) coupled with krill lipid data obtained from 3 years of fishery-derived samples. We examined within and between year variation of trends in both the environment and krill biochemistry data. Chlorophyll a levels were positively related to krill lipid levels, parti...

Euphausiids have been well studied in several regions of the Pacific Ocean; however, there is lessinformation regarding euphausiids in Costa Rican waters. We analyzed euphausiid specimens collected aroundIsla del Coco National Park during 2011 and 2012. A total of 130 specimens were analyzed and 13 euphausiidspecies were identified, belonging to four genera and one family. An annotated list of species is presented,with photographs and details for their identification. All species found represent new records for waters aroundIsla del Coco in the Costa Rican Pacific. The most frequent species were Euphausia diomedeae, Euphausiadistinguenda, Nematoscelis gracilis and Stylocheiron affine. Rev. Biol. Trop. 64 (Suppl. 1): S221-S230. Epub2016 Febrary 01.

Diel vertical migration (DVM) of krill was studied throughout 36 h at a fixed station (46.05°S, 66.19°W; 98-m depth) located in the center of the San Jorge Gulf, Southern Patagonia area, during February 2014. Using an echosounder system, combined with an autonomous Video Plankton Recorder (Auto-VPR) and Jacknet samplings, we describe the migration pattern, the associated biomass and the macrozooplankton species involved. The net sampling and the Auto-VPR images allowed us to identify the krill species detected in the echosounder signals, which corresponded to Euphausia lucens, Euphausia vallentini and Nematoscelis megalops. The krill community followed a “normal pattern” of DVM, ascending at dusk (~18:30 h) and descending at dawn (~06:30 h), forming a dense layer near the bottom during the day. Krill vertical migration speed was estimated from the echogram data at ~ 1 cm s−1 (1 body length per s for 1-cm-long animal), and the integrated mean biomass was 57.8 g m−2. This study provid...

O óleo de krill é um suplemento benéfico para a saúde das articulações? dicasetruquesdemaquiagem.over-blog.com/o-oleo-de-krill-e-um-suplemento-benefico-para-a-saude-das-articulacoes.html O óleo de krill é um suplemento benéfico para a saúde das articulações? A fisioterapia pode ser prescrita por médicos para ajudar a distribuir a pressão e aliviar o estresse em uma articulação. O uso de óleo de krill é outra forma natural de melhorar a saúde das articulações. É rico em ácidos graxos ômega-3 e astaxantina, que podem ajudar na mobilidade das articulações. As infecções articulares podem afetar qualquer pessoa, e a prevenção geralmente é preferível ao tratamento. Isso vale para todas as condições de saúde, pois podem comprometer o sistema imunológico. =>> Ver => https://bit.ly/oleodekrill Os médicos recomendam o óleo de krill como suplemento porque contém ácidos graxos ômega-3 essenciais que permitem que as articulações se movam com mais liberdade. Pacientes com problemas de saúde nas articulações têm maior risco de desenvolver doenças cardíacas. Dores nas articulações em várias partes do corpo podem causar ataques cardíacos. O óleo de krill auxilia na restauração da saúde e do ritmo cardíaco normal. No entanto, para manter a sua saúde geral, é recomendável que você obedeça rigorosamente às instruções de dosagem do seu médico. Uma das coisas mais recomendadas para reduzir o desconforto e as dores causadas pelas dores nas articulações é seguir uma dieta saudável rica em ácidos graxos ômega 3. Como todos sabemos, a dieta ocidental média é deficiente em ácidos graxos ômega 3, e os suplementos geralmente são a única maneira de obter esses ácidos graxos essenciais. O óleo de krill passou por extensos estudos e é amplamente utilizado em hospitais. Também foi demonstrado que ajuda no tratamento de dores nas articulações associadas à TPM. Além disso, os idosos que são mais suscetíveis a dores nas articulações encontraram uma melhora nas articulações após o uso do óleo. =>> Ver => https://bit.ly/oleodekrill As doenças articulares podem prejudicar a circulação sanguínea, resultando em ataques cardíacos e arritmia ventricular. Muitos profissionais médicos sugeriram o óleo de krill como uma cura eficaz para problemas de saúde nas articulações. Apesar de o óleo de krill

The Antarctic krill (Euphausia superba Dana, 1850) is an important trophic link between phyto-plankton and higher trophic levels. Knowledge of the lipid biochemistry of krill assists in understanding their seasonal biology and predicting their responses to ecological changes. We collected daily samples of krill from a commercial fishing vessel operating in the Atlantic Sector of the Southern Ocean from 2014 to 2016. We analysed the total lipid content of krill sampled every two weeks and the relative distribution of lipid class levels to examine seasonal trends. Krill total lipid content varied significantly within and between seasons and sexes. An annual sinusoidal trend was seen in total lipid content with the highest values in autumn and the lowest in spring (average 380 and 87 mg/g dry mass, respectively). Total lipids in krill increased during summer, peaking in autumn, with the total lipids in winter individuals decreasing towards spring. The relative distribution of lipid class levels varied between season and year. Levels of triacylglycerol showed the same seasonal trend as total lipid content, whilst phospholipid showed the inverse trend indicating the contrasting roles of these two dominant lipid classes. These data provide high-resolution information on the seasonality of krill lipid content and composition. This information has both ecological and commercial utility.

Euphausiids have been well studied in several regions of the Pacific Ocean; however, there is less information regarding euphausiids in Costa Rican waters. We analyzed euphausiid specimens collected around Isla del Coco National Park during 2011 and 2012. A total of 130 specimens were analyzed and 13 euphausiid species were identified, belonging to four genera and one family. An annotated list of species is presented, with photographs and details for their identification. All species found represent new records for waters around Isla del Coco in the Costa Rican Pacific. The most frequent species were Euphausia diomedeae, Euphausia distinguenda, Nematoscelis gracilis and Stylocheiron affine. Rev. Biol. Trop. 64 (Suppl. 1): S221-S230. Epub 2016 Febrary 01.

Euphausiid krill play a critical role in coastal and oceanic food webs, linking primary producers to upper trophic levels. In addition, some species support commercial fisheries worldwide. Despite their ecological importance, the genetics of these important species remain poorly described. To improve our understanding of the genetics of these ecological links, we sequenced the mitochondrial genomes of two species of North Pacific krill, Euphausia pacifica and Thysanoessa raschii, using long-range PCR and 454 GS Junior next-generation sequencing technology. The E. pacifica mitogenome (14,692 ? base pairs (bp)) encodes 13 protein-coding genes (PCGs), two ribosomal RNA (rRNA) genes, and at least 22 transfer RNA (tRNA) genes. The T. raschii mitogenome (14,240 ? bp) encodes 13 PCGs, two rRNA genes, and at least 19 tRNA genes. The gene order in both species is similar to that of E. superba. Comparisons between Bering Sea and Yellow Sea E. pacifica revealed a total of 644 variable sites. The most variable protein-coding gene were atp8 (7.55 %, 12 of 159 sites variable), nad4 (6.35 %, 85 variable sites) and nad6 (6.32 %, 33 variable sites). Phylogenetic analyses to assess the phylogenetic position of the Euphausiacea, using the concatenated nucleic acid sequences of E. pacifica and T. raschii along with 46 previously published malacostracan mitogenomes, support the monophyly of the order Decapoda and indicate that the Euphausiacea share a common ancestor with the Decapoda. Future research should utilize this sequence data to explore the population genetics and molecular ecology of these species.

Plerocerci of the monotypic Paranybelinia otobothrioides were found parasitizing the subtropical neritic krill Nyctiphanes simplex in the Gulf of California, Mexico. The plerocerci were recovered from two microhabitats of the intermediate host, typically embedded inside the digestive gland (hepatopancreas) or rarely in the hemocoel. The morphology of the simple, single-layered blastocyst surrounding the entire scolex is unique within the Trypanorhyncha by having four large funnel-like pori or openings possibly with feeding and/or excretory function. One of the openings is located anteriorly and three at the posterior end. Scolex surface ultrastructure shows hamulate and lineate spinitriches covering the bothrial surface, capilliform filitriches at the anterior scolex end and on the scolex peduncle, and short papilliform filitriches on the long appendix. This pattern resembles that of species of the Tentaculariidae; but differs in that the hamulate spinitriches, which appear lineate at the bothrial margins, densely cover the entire distal bothrial surface. Tegumental grooves are present on the posterior bothrial margin, lacking spinitriches. Paranybelinia otobothrioides and Pseudonybelinia odontacantha share the following unique combination of characters: two bothria with free lateral and posterior bothrial margins, homeoacanthous homeomorphous armature, tegumental grooves, the distribution of the hamulate spinitriches, and the absence of prebulbar organs. Both genera infect euphausiids as intermediate hosts. Sequence data of the partial ssrDNA gene place Pa. otobothrioides sister to the family Tentaculariidae, and the Kimura two-parameters (K2P) distance between Pa. otobothrioides and species of the family Tentaculariidae ranged from 0.027 to 0.039 (44-62 nucleotide differences). These data suggest both species be recognized in a family, the Paranybeliniidae, distinct from, albeit as sister taxon to, the Tentaculariidae. High prevalence of infection (< 14%) and ontogenetic changes of Pa. otobothrioides support N. simplex as a required intermediate host and suggest a zooplanktophagous elasmobranch as final host in the Gulf of California.

Krill, small crustaceans of the family “euphausiid”, are a central trophic link in the marine
food web of the California Current ecosystem, but recent trends show a decline in krill
abundance, in particular of E. pacifica off Oregon and California. This paper offers a geographic
atlas of the spatial organization of E. pacifica with the aim of identifying krill
“hotspots” for conservation priorities. The spatial organization of E. pacifica is strongly associated
with patterns of coastal upwelling along the continental shelf break area as well as
specific bathymetric features, such as canyons and islands. It is the co-occurrence of these
two conditions that create an “optimal environmental window” for krill, characterized by both
high nutrient availability and a secure habitat. Based on these “hotspots” the paper puts forward
a management recommendation. Conservationists need to elevate the status of krill
“hotspots” from areas where fishing for krill is simply banned to a more comprehensive system
of “Marine Protected Areas” which offer additional protection for krill-dependent predators
as well.