Browsing Brage IMR by Author "Ostrowski, Marek"
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Abundance estimation of Norwegian spring spawning herring wintering in the Vestfjord system, December 1996
Ostrowski, Marek; Foote, Kenneth G.; Røttingen, Ingolf; Slotte, Aril (ICES CM Documents;1997/FF:13, Working paper, 1997)The spawning stock of Norwegian spawning herring has been surveyed when wintering in the Vestfjord, Tysfjord, and Ofotfjord, in northem Norway in December 1996. The basic method is that of echo integration, with compensation ... -
Acoustic abundance estimation of the stock of Norwegian spring spawning herring, winter 1995- 1996
Foote, Kenneth G.; Ostrowski, Marek; Røttingen, Ingolf; Engås, Arill; Hansen, Kaare A.; Hauge, Kjellrun Hiis; Skeide, Roar L.; Slotte, Aril; Torgersen, Øyvind (ICES CM Documents;1996/H:33, Working paper, 1996)Standard echo integration methodology has been applied to the stock of Norwegian spring spawning herring (Clupea harengus) wintering in the Ofotfjord-Tysfjord-Vestfjord system during late autumn 1995 and early winter ... -
Acoustic portrait of herring in Vestfjord, january 1996, with geostatistical analysis
Foote, Kenneth G.; Ostrowski, Marek (ICES CM Documents;1996/H:31, Working paper, 1996)In January 1996 the stock of Norwegian spring-spawning herring (Clupea harengus) was acoustically surveyed in the wintering area. Both immature and mature fish were present. Because of the comparative lateness of the ... -
Asynchronized spawning responses of small pelaigic fish to a short-term enviromental change
Tiedemann, Maik; Ndour, Ismaïla; Sow, Fambaye Ngom; Bagøien, Espen; Krakstad, Jens-Otto; Ostrowski, Marek; Stenevik, Erling Kåre; Ensrud, Tor Magne; Isari, Stamatina (Peer reviewed; Journal article, 2022)We provide substantial evidence on how short-term changes in environmental conditions activate and deactivate spawning activities in small pelagic fishes. An ichthyoplankton survey was conducted along the southernmost part ... -
Bathymetric conformal variography of the spawning stock of Northern blue whiting
Foote, Kenneth G.; Ostrowski, Marek (ICES CM Documents;1996/S:46, Working paper, 1996)Bathymetric-based conformal isotropic and anisotropic variograms are defined. These are applied to the spawning stock of northern blue whiting (Micromesistius poutassou) along the slope of the continental shelf west of the ... -
Dynamics of wintering Norwegian spring-spawning herring at the entrance to Tysfjorden, December 1996
Huse, Ingvar; Foote, Kenneth G.; Ostrowski, Marek (ICES CM Documents;1997/CC:16, Working paper, 1997)The entrance region to Tysfjorden was acoustically surveyed a total of eleven times during the December 1996 abundance survey of the spawning stock of Norwegian spring-spawning herring (Clupea harengus). The observations ... -
Eastern boundary circulation and hydrography off Angola building Angolan oceanographic capacities
Tchipalanga, Pedro C.M.; Dengler, Marcus; Brandt, Peter; Kopte, Robert; Macuéria, Marisa; Coelho, Paulo; Ostrowski, Marek; Keenlyside, Noel (Journal article; Peer reviewed, 2018)The eastern boundary region off Angola encompasses a highly productive ecosystem important for the food security of the coastal population. The fish-stock distribution, however, undergoes large variability on intraseasonal, ... -
Impact of equatorial Kelvin waves on aggregations of sardinellas (Sardinella spp.) in Angolan waters.
Ostrowski, Marek (ICES CM documents;2007/G:08, Working paper, 2007)High yields of pelagic fish in Angolan tropical waters are associated with seasonal upwelling. The Angolan upwelling is forced by a large-scale eastward tilt of the main thermocline in the tropical Atlantic. Near the ... -
An object-based approach to integration of software to support management and reporting of marine ecosystem survey data
Ostrowski, Marek (ICES CM documents, Working paper, 2006)An object-based software to support distributed databases and data reporting from combined fisheries and environmental surveys is presented. The key abstraction of this system is expressed as a generic station (data) object. ... -
Oxygen and temperature influence the distribution of deepwater Cape hake Merluccius paradoxus in the southern Benguela: a GAM analysis of a 10-year time-series
Mbatha, FL; Yemane, D; Ostrowski, Marek; Moloney, Coleen L; Lipinski, MR (Journal article; Peer reviewed, 2019)Generalised additive models (GAMs) were applied to survey data to assess the influence of dissolved oxygen, water temperature and year of sampling upon the presence/absence of small (≤15 cm TL), medium (16–34 cm TL) and ... -
Quality control and preparation of acoustic survey data for treatment by spatial analysis techniques. Experiences from using integrated visualization software tools.
Ostrowski, Marek (ICES CM documents, Working paper, 1998) -
Seasonal Cycle of Sea Surface Salinity in the Angola Upwelling System
Awo, F.M.; Rouault, M.; Ostrowski, Marek; Tomety, F.S.; Da-Allada, C.Y.; Jouanno, J. (Peer reviewed; Journal article, 2022)The seasonal cycle of sea surface salinity (SSS) along the Angolan coast is investigated using observations and a regional ocean model. The model reproduces the main characteristic of the seasonal cycle of SSS along the ... -
Southeastern Tropical Atlantic Changing From Subtropical to Tropical Conditions
Roch, Marisa; Brandt, Peter; Schmidtko, Sunke; Vaz Velho, Filomena; Ostrowski, Marek (Peer reviewed; Journal article, 2021)A warming and freshening trend of the mixed layer in the upper southeastern tropical Atlantic Ocean (SETA) is observed by the Argo float array during the time period of 2006–2020. The associated ocean surface density ... -
The Angola Current: Flow and hydrographic characteristics as observed at 11?S
Kopte, R; Brandt, P.; Dengler, M; Tchipalanga, Pedro C.M.; Macuéria, Marisa; Ostrowski, Marek (Peer reviewed; Journal article, 2017) -
The Hermes Lander project - the technology, the data, and the evaluation of concept and results
Godø, Olav Rune; Tenningen, Eirik; Ostrowski, Marek; Kubilius, Rokas; Kutti, Tina; Korneliussen, Rolf J.; Fosså, Jan Helge (Fisken og havet;3-2012, Research report, 2012)This report summarizes technology, operations, experience, and scientific results from the Hermes Lander project. The Project established an autonomous, multi-sensor, sub-sea sensor platform powered by batteries. The ... -
Tidally-forced lee waves drive turbulent mixing along the Arctic Ocean margins
Fer, Ilker; Koenig, Zoé Charlotte; Kozlov, Igor E.; Ostrowski, Marek; Rippeth, Tom; Padman, L.; Bosse, Anthony; Kolås, Eivind (Peer reviewed; Journal article, 2020)In the Arctic Ocean, limited measurements indicate that the strongest mixing below the atmospherically forced surface mixed layer occurs where tidal currents are strong. However, mechanisms of energy conversion from tides ... -
Utarbeidelse av et program for overvåkning av eutrofitilstand og- utvikling i norske kystfarvann basert på både tradisjonelle og høyteknologiske metoder
Ottersen, Geir; Aasen, Svein Erik; Aure, Jan; Danielssen, Didrik S.; Johnsen, Torbjørn Martin; Ostrowski, Marek; Skjoldal, Hein Rune; Svendsen, Einar; Søiland, Henrik; Sørensen, Kai; Tangen, Karl (Fisken og havet, Research report, 1998)This report describes methods for enhancement of the curent strategy for cutrophication surveillance through a case study of the Skagerrak region. As a basis for evaluation of different methods for monitoring ... -
Validation and sensitivity study of a Sigma-coordinate ocean model using the Skagex dataset
Berntsen, Jarle; Svendsen, Einar; Ostrowski, Marek (ICES CM Documents;1996/C:5, Working paper, 1996)Numerical ocean models are now being applied in numerous oceanographic studies. However, standards and procedures for evaluation of these models are far from established. In this paper the use of data from hydrographical ... -
Variation in acoustically measured abundance from repeated surveys of herring
Huse, Ingvar; Ostrowski, Marek (ICES CM documents, Working paper, 1998)A large concentration of wintering herring was surveys continuously with acoustics over 37 hours in a fjord in Northern Norway. 16 surveys of the same area were conducted. Total abundance and statistics were computed for ... -
Where and How the East Madagascar Current Retroflection Originates?
Ramanantsoa, Heriniaina Juliano Dani; Penven, Pierrick; Pappukutty, Raj Roshin; Renault, Lionel; Ponsoni, L; Ostrowski, Marek; Dilmahamod, A.F; Rouault, M (Peer reviewed; Journal article, 2021)The East Madagascar Current (EMC) is one of the western boundary currents of the South Indian Ocean. As such, it plays an important role in the climate system by transporting water and heat toward the pole and recirculating ...