![]() | The state of the art of IFREMER in tropical aquaculture Auteur(s) : Calvas, Jacques Éditeur(s) : Actes de colloques Ifremer, Tahiti, French Polynesia, 20 Feb - 4 Mar 1989, n°9, chap. 1, pp.3-9 Résumé : IFREMER, a French governmental agency, is engaged in research on tropical aquaculture since 1971, with the aims to develop new activities in French overseas territories and to export French technology to foreign countries. With 80 searchers and technicians the "Centre Oceanologique du Pacifique" is the main IFREMER's centre involved in tropical aquaculture. The research has been focused on the complete control of the whole cycle: constitution of broodstock, maturation and reproduction, larval rearing, and grow-out. Droits : info:eu-repo/semantics/openAccess http://archimer.ifremer.fr/doc/1989/acte-1500.pdf http://archimer.ifremer.fr/doc/00000/1500/ | Partager |
![]() | Diversifying fishing effort in Sicilian fisheries: the case of Fish Aggregating Devices (FADs) Auteur(s) : Cannizzaro, L Bono, G Rizzo, P Potoshi, A Celesti, A Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999 Résumé : In the Sicilian fisheries, the swordfish (Xiphias gladius, Linnaeus 1758), caught from March to December with several gears which vary according to season, represents one of the most important economic resources. The size composition changes depending on the gear used, the way it is operated, the fishing area and season. The gears used for swordfish fishing (long-lines "for swordfish", drift-nets, harpoons as operated by typical boats named "feluche") mainly catch adult specimens. From August to December, a high number of very young swordfish specimens (1.5 to 4.5 kg) is also caught as by-catch during the albacore (Thunnus alalunga, Bonnaterre 1788) fishing which is carried out by a special long line and hooks only 3 cm long. It was observed that in the same season, fishing areas and with boats of similar type, the fishing of dolphin-fish (Coryphaena hippurus, Linnaeus 1758), using Fish Aggregating Devices (FADs) and purse seine, is hardly practised in spite of the resource availability swordfish. With the present work, which can be regarded as an initial approach to the problem of diversifying and managing fishing effort of swordfish, albacore and dolphin-fish, their fisheries are examined and discussed, not overlooking the economic aspect, by considering weather a reallocation of fishing effort among the previously said resources might avert the risk of swordfish stock depletion. Droits : info:eu-repo/semantics/openAccess http://archimer.ifremer.fr/doc/00042/15299/12659.pdf http://archimer.ifremer.fr/doc/00042/15299/ | Partager Voir aussi Attracting techniques Fishing effort Tuna fisheries Article Geographic Terms: MED, Italy, Sicilia Télécharger |
![]() | Spatio-temporal variability in benthic silica cycling in two macrotidal estuaries: Causes and consequences for local to global studies Auteur(s) : Raimonet, Melanie Ragueneau, Olivier Andrieux Loyer, Francoise Philippon, Xavier Kerouel, Roger Le Goff, Manon Memery, Laurent Éditeur(s) : Academic Press Ltd- Elsevier Science Ltd Résumé : The high heterogeneity of silica cycling in coastal margins and the lack of silica data (compared to nitrogen and phosphorus) prevent the estimation of global silica retention in estuaries. In this study, the spatial and temporal variability of porewater silicic acid (Si(OH)4) profiles e that integrate benthic transport and reaction processes e was investigated at different spatial (metre, longitudinal and crosssection, intra-estuary) and temporal (tidal, seasonal) scales in two macrotidal estuaries, very close geographically but essentially differing in their shape. Studying the spatial and temporal variability of Si(OH)4 concentrations in porewaters provided evidence for the importance of transport processes, e.g. bio-irrigation, tidal pumping, resuspension and any combination of these processes, in affecting Si(OH)4 concentrations and fluxes and therefore temporary or permanent retention along the landeocean continuum. We confirm that aSiO2 (amorphous silicate) transported by rivers and estuaries clearly needs to be better characterized as it provides an important source of reactive aSiO2 to sediments. This study allows us to: (1) interrogate spatial and temporal scales, although both are most often in complete interaction; (2) design the most appropriate sampling schemes to be representative of any given system and to extrapolate at the scale of the whole estuary; (3) quantify uncertainty associated to the estimations of Si(OH)4 stocks and fluxes in this type of ecosystem, essential for budget calculations. We showed that two adjacent small macrotidal estuaries, may exhibit different behaviours regarding Si retention. Temporary retention has been observed in the meanders of the Aulne Estuary and not along the more linear Elorn Estuary, demonstrating the importance of the morphology and hydrodynamic components of the estuarine filter. Research is needed in other systems and climatic zones, but our study suggests that the typology should not only account for the different types of landeocean continuum (fjord, delta, mangrove.), but also incorporate the physical or biological attributes of the estuarine filter. Estuarine Coastal And Shelf Science (0272-7714) (Academic Press Ltd- Elsevier Science Ltd), 2013-03 , Vol. 119 , P. 31-43 Droits : 2013 Elsevier Ltd. All rights reserved. http://archimer.ifremer.fr/doc/00124/23529/22370.pdf DOI:10.1016/j.ecss.2012.12.008 http://archimer.ifremer.fr/doc/00124/23529/ | Partager |