Transport of Antarctic krill (Euphausia superba) across the Scotia Sea. Part II. Krill growth and survival

A time-dependent, size-structured, physiologically based krill growth model was used in conjunction with a circulation model to test the hypothesis that Antarctic krill (Euphausia superba) populations at South Georgia are sustained by import of individuals from upstream regions. Surface phytoplankton concentrations along the simulated drifter trajectories were extracted from historical Coastal Zone Color Scanner (CZCS) measurements and sea ice biota concentrations were calculated from sea ice concentration and extent extracted along drifter trajectories from Special Sensor Microwave/Imager measurements. As additional food sources, a time series of heterotrophic food was constructed from historical data, and time series of detritus concentrations were calculated using phytoplankton concentrations extracied from CZCS measurements together with measured particulate organic carbon to chlorophyll a ratios. These food resources along specified drifter trajectories were then input to the krill growth model to determine the size and viability of krill during transport from the source region to South Georgia. The krill growth model simulations showed that no single food source can support continuous growth of krill during the 58-306 days needed for transport to South Georgia. However, under the current assumptions results indicate that combinations of food sources during the transport time enhanced krill survival, with heterotrophic food and detritus being particularly important during periods of low phytoplankton concentrations. The growth model simulations also showed that larval and juvenile krill originating along the western Antarctic Peninsula can grow to 1+ (14-36mm) and 2+ (26-45 mm) age and size classes observed at South Georgia during the time needed for transport to this region. Krill originating in the Weddell Sea need 20 months for transport, which allows retention in a potentially high food environment, provided by sea ice, for almost 1 year. Krill then complete transport to South Georgia in the following year and larval and juvenile krill grow to 2+ (26-45 mm) and 3+ (35-60 mm) age and size classes during transport. The results of this study show that the successful transport of krill to South Georgia depends on a multitude of factors, such as the location of the spawning area and timing of spawning, food concentrations during transport, predation, and variations in the location of the Southern Antarctic Circumpolar Current Front (SACCF) and in sea ice extent.


Biochemically based modeling study of Antarctic krill Euphausia superba growth and development
Fach Salihoğlu, Bettina Andrea; Wolf-Gladrow, Dieter; Bathmann, Ulrich (2008-01-01)
A biochemical model of Antarctic krill Euphausia superba was developed to investigate the physiological mechanisms which enable krill to survive winter, when food is scarce. In this modeling approach data sets on the biochemical composition of krill and its food sources are combined into a model that takes food quality into account rather than just food availability during different seasons. Krill is defined in terms of protein, neutral lipid, polar lipid, carbohydrate, chitin, and ash content, and the mode...
Implementation of Antarctic Krill into the Ocean-Ecosystem Model FESOM-REcoM-2 and its Effects on Southern Ocean Biogeochemistry.
Karakus, Onur; Hauck, Judith; Völker, Christoph; Fach Salihoğlu, Bettina Andrea; Hagen, Wilhelm (2020-01-16)
In this study, a three-dimensional, coupled ocean ecosystem model (FESOM- REcoM2) is used to investigate the effect of krill on the biogeochemistry of the Southern Ocean. The implementation of Antarctic krill in the model was done in three steps. 1) A second zooplankton group was implemented, which grazes on diatoms, mesozooplankton and nanophytoplankton (in order of descending preference). 2) A new detritus group was added to the model, which represents faster-sinking krill faecal pellets. 3) The grazing i...
Population dynamics and ecology of the invasive veined rapa whelk, Rapana venosa in the southern Black Sea
MUTLU, ERHAN; Kıdeyş, Ahmet Erkan; Şahin, Fatih; Erik, Gökhan; Aksu, Hakan; Erdem, Ercan; Karayücel, Sedat; Bat, Levent (2022-05-05)
© 2022 Elsevier LtdSpatial and temporal changes in some ecological characteristics (i.e. biomass, abundance, morphometrics, sex-composition, growth parameters and population dynamics) of the invasive veined rapa whelk (Rapana venosa) were studied off Sinop Bay, in the southern Black Sea. The whelk specimens were sampled from three depths (15 m, 25 m and 35 m) at monthly intervals between November 2005 and October 2007. Custom-made pots were deployed for the capture of R. venosa individuals. Monthly distribu...
Modeling studies of antarctic krill Euphausia superba survival during transport across the Scotia Sea
Fach Salihoğlu, Bettina Andrea; MURPHY, EUGENE (2002-01-01)
Antarctic krill Euphausia superba spawned on the outer continental shelf of the west Antarctic Peninsula can be entrained into the Southern Front of the Antarctic Circumpolar Current and transported across the Scotia Sea to South Georgia. A time-dependent, size-structured, physiologically based krill growth model was used to assess the food resources that are needed to sustain Antarctic krill during transport across the Scotia Sea and to allow them to grow to a size observed at South Georgia. Initial Lagran...
Factors affecting fledging weight of Adelie penguin (Pygoscelis adeliae) chicks: a modeling study
Salihoğlu, Barış; Hofmann, EE (2001-05-01)
An individual-based model is developed to examine mechanisms that potentially underlie the observed constancy in fledging weight (2.8-3.2 kg) of Adelie (4Pygoscelis adeliae) penguin chicks, in spite of large variability in the abundance of Antarctic krill (Euphausia superba), the primary food source. The model describes the energetic requirements of the chick. with growth resulting from the difference between assimilated energy and respiration. Parameterizations of these metabolic processes are based upon e...
Citation Formats
B. A. Fach Salihoğlu and E. J. Murphy, “Transport of Antarctic krill (Euphausia superba) across the Scotia Sea. Part II. Krill growth and survival,” DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS, pp. 1011–1043, 2006, Accessed: 00, 2020. [Online]. Available: