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| Demer, Da; Berger, Laurent; Bernasconi, M; Bethke, E; Boswell, K; Chu, D; Domokos, R; Dunford, A; Fassler, S; Gauthier, S; Hufnagle, Lt; Jech, Jm; Le Bouffant, Naig; Lebourges-dhaussy, Anne; Lurton, Xavier; Macaulay, Gj; Perrot, Yannick; Ryan, T; Parker-stetter, S; Stienessen, S; Weber, T; Williamson, N. |
| Acoustic instrument calibration is fundamental to the quantitative use of its data for estimating aquatic resource abundance. Regular calibrations also allow instrument performance to be monitored to detect changes due to the environment or component dynamics, degradation, or failure. This is the second ICES Cooperative Research Report (CRR) focussed on calibrations of acoustic instruments. The first, CRR No. 144 (Foote et al., 1987), was published during the era of analogue electronics more than a quarter of a century ago. Since then, not only has the acoustic equipment improved vastly with digital electronics and signal processing, but the techniques for applying them to studies of marine organisms have both advanced and diversified. Motivating,... |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00586/69821/67711.pdf |
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| Diogoul, Ndague; Brehmer, Patrice; Perrot, Yannick; Tiedemann, Maik; Abou Thiam,; El Ayoubi, Salaheddine; Mouget, Anne; Migayrou, Chloe; Sadio, Oumar; Sarre, Abdoulaye. |
| Understanding the relationship between sound-scattering layers (SSLs) and pelagic habitat characteristics is a substantial step to apprehend ecosystem dynamics SSLs are detected on echo sounders representing aggregated marine pelagic organisms. In this study, SSL characteristics of zooplankton and micronekton were identified during an upwelling event in two contrasting areas of the Senegalese continental shelf. Here a cold upwelling-influenced inshore area was sharply separated by a strong thermal boundary from a deeper, warmer, stratified offshore area. Mean SSL thickness and SSL vertical depth increased with the shelf depth. The thickest and deepest SSLs were observed in the offshore part of the shelf. Hence, zooplankton and micronekton seem to occur... |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00606/71777/70261.pdf |
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| Fromant, G.; Floc'H, F.; Lebourges-dhaussy, Anne; Jourdin, F.; Perrot, Yannick; Le Dantec, N.; Delacourt, Christophe. |
| The study of the suspended particulate matter (SPM) transport is essential to understanding oceans and rivers, for their presence can impact the environment, from marine habitats or water quality degradations to important changes of the seabed morphology. Among a large number of surrogate techniques in traditional water sampling, acoustical methods have the advantage of providing nonintrusive measurements, with high spatial and temporal resolutions. However, the ability of fine-grained sediments to aggregate under the process of flocculation complexifies the interpretation of acoustical measurements. The objective of this paper is to design a simple backscatteringmodel for flocculated sediment suspensions, in order to interpret the information provided by... |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00616/72809/72590.pdf |
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| Diogoul, Ndague; Brehmer, Patrice; Demarcq, Herve; El Ayoubi, Salaheddine; Thiam, Abou; Sarre, Abdoulaye; Mouget, Anne; Perrot, Yannick. |
| The resistance of an east border upwelling system was investigated using relative index of marine pelagic biomass estimates under a changing environment spanning 20-years in the strongly exploited southern Canary Current Large marine Ecosystem (sCCLME). We divided the sCCLME in two parts (north and south of Cap Blanc), based on oceanographic regimes. We delineated two size-based groups (“plankton” and “pelagic fish”) corresponding to lower and higher trophic levels, respectively. Over the 20-year period, all spatial remote sensing environmental variables increased significantly, except in the area south of Cap Blanc where sea surface Chlorophyll-a concentrations declined and the upwelling favorable wind was stable. Relative index of marine pelagic... |
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| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00676/78789/81019.pdf |
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