|
|
|
| Registros recuperados: 25 | |
|
|
| Trenkel, Verena; Mazauric, Valerie; Berger, Laurent. |
| Recently, Simrad in collaboration with Ifremer developed a calibrated, multibeam, vertical echosounder (ME70) for fisheries research. We describe its capabilities and technical limitations. The ME70 has up to 45 beams with distinct frequencies in the range 70120 kHz, spanning at most 150 degrees. All beams are stabilized in vessel roll and pitch. It has reduced side-lobe levels, up to -70 dB (two-way) instead of the -2S dB (one-way) of conventional systems. We outline research areas for which the ME70 might provide new types of information and hence lead to novel insights. We illustrate the potential contributions with datasets collected in the English Channel and on the continental-shelf break of the Bay of Biscay. Finally, future research and... |
| Tipo: Text |
Palavras-chave: Three dimensional; Behaviour; Acoustics; Abundance. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4117.pdf |
| |
|
|
| Petitgas, Pierre; Goarant, Anne; Masse, Jacques; Bourriau, Paul. |
| Petitgas, P., Goarant, A., Masse, J., and Bourriau, P. 2009. Combining acoustic and CUFES data for the quality control of fish-stock survey estimates. - ICES Journal of Marine Science, 66: 1384-1390. |
| Tipo: Text |
Palavras-chave: CUFES; Biscay; Bias; Anchovy; Acoustics; Abundance. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6566.pdf |
| |
|
|
| Berger, Laurent; Poncelet, Cyrille; Trenkel, Verena. |
| Fish schools can be insonified simultaneously with multifrequency echosounders (e.g. Simrad EK60s) and a multibeam echosounder (e.g. Simrad ME70). This paper presents a method for combining these data to improve estimates of the relative frequency response r(f) of fish schools. Values of r(f) are now commonly used to classify echoes in fishery surveys. The data from the roll- and pitch-stabilized, high-resolution ME70 are used to correct beam-width effects in the multifrequency EK60 data. First, knowing the exact position and orientation of the transducers and the position of the vessel, the echoes are placed into a common geographic coordinate system. Then, the EK60 data are rejected if they do not include a significant percentage of the fish school... |
| Tipo: Text |
Palavras-chave: Species identification; Scomber scombrus; Sardina pilchardus; Pelagic fish; Acoustics. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6590.pdf |
| |
|
|
| Krakstad, Jens-Otto; Amaro, Aristóteles P. da S.; Shigwedha, Vaino. |
| The main objectives of the survey were the following: • To map the distribution and estimate the abundance of the most commercially important pelagic species in the Namibia-Angola transboundary area (15°50-19°00’), following the survey design utilized in Angolan waters (6 n.mi spacing between transect lines), with special emphasis on the two horse mackerel Cunene horse mackerel (Trachurus trecae) and Cape horse mackerel (Trachurus capensis), sardine “Pilchard” (Sardinops sagax) and other small pelagic species, including anchovy (Engraulis capensis) and round herring (Etrumeus whiteheadi). • To map the distributions and estimate the abundance of the same species in central Namibia south to Dune Point (20°15’ S), following the established survey design with... |
| Tipo: Report |
Palavras-chave: Pelagic fisheries; Fishery surveys; Acoustics; Sampling; Trawls; Oceanography; Biomass; Distribution; Composition. |
| Ano: 2012 |
URL: http://hdl.handle.net/1834/5230 |
| |
|
| |
| Registros recuperados: 25 | |
|
|
|
