|
|
|
|
|
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 |
| |
|
|
Dransfeld, Leonie; Gerritsen, Hans D.; Hareide, Nils R.; Lorance, Pascal. |
With slow growth rates, late maturity and a high maximum age of 100 years or more, orange roughy can be classified as a vulnerable deepwater fish species that can only sustain low rates of exploitation. Historical patterns of exploitation associated with this species suggest that it is currently not possible to manage its fisheries in the Northeast Atlantic sustainably, and the total allowable catch for orange roughy has been gradually reduced to zero for European fisheries since 2010. Orange roughy to the west of Ireland and Britain occurs on distinct bathymetric features (seamounts, hills and canyons) as well as on flat ground along the continental slope. Productivity-susceptibility analysis (PSA) was performed to evaluate the biological vulnerability of... |
Tipo: Text |
Palavras-chave: Ecological risk assessment; VMS; Continental slope; Beryciformes; Atlantic Ocean. |
Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00176/28758/27234.pdf |
| |
|
|
|