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Bez, Nicolas; Reid, David; Neville, Suzanna; Verin, Yves; Hjellvik, Vidar; Gerritsen, Hans D.. |
Acoustic data are often collected during bottom trawl surveys. Their use can potentially improve the precision and accuracy of fish abundance estimates if acoustic data collected between trawl stations are consistent with those collected during trawling operations. This question is addressed here through the analysis of 20 bottom trawl surveys (three survey areas and five different survey series) with coincident acoustic measurements during and between trawl stations. Firstly, on-station and underway acoustic data were compared using statistics computed globally over each survey (average vertical profiles, global indices of collocations, and spatial structures) for various combinations of depth layers. Secondly, we focussed on underway acoustic data... |
Tipo: Text |
Palavras-chave: Gear perturbation; Acoustic; Bottom trawl. |
Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2486.pdf |
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Nicolaus, E. E. Manuel; Barry, Jon; Bolam, Thi P. C.; Lorance, Pascal; Marandel, Florianne; Phillips, Sophy R. Mccully; Neville, Suzanna; Ellis, Jim R.. |
Trace metal concentrations in muscle and liver tissues from two offshore species of skate were examined. Concentrations of mercury in muscle of Leucoraja circularis (n = 20; 23–110.5 cm total length, 157–490 m water depth) and L. fullonica (n = 24; 28.5–100 cm total length, 130–426 m water depth) were 0.02–1.8 and 0.04–0.61 mg kg− 1, respectively. Concentrations of both As and Hg increased with total length. Only the largest specimen had a concentration of Hg in muscle > 1.0 mg kg− 1. Data were limited for specimens > 90 cm long, and further studies on contaminants in larger-bodied skates could usefully be undertaken. |
Tipo: Text |
Palavras-chave: Trace metals; Sandy ray; Shagreen ray; Bay of Biscay; Celtic Sea. |
Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00397/50829/51592.pdf |
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