commercial longliner between November 2007 and April 2008 in international waters of the SW Atlantic. During our study sperm whales were sighted during 35% of hauls, always during gear retrieval and usually solitary although groups of up to 5 animals were seen. Sightings were related to time of day, moon phase and SST. Damage to fish was observed during 8% of hauls and sperm whales were sighted during 71% of these depredation events. The overall depredation rate (0.44% of total toothfish catch) was low, but assumed to be underestimated since sperm whales were also suspected to take entire fish from the line without leaving visual evidence. The MBEDs proved to be highly effective in preventing accidental by-catch of seabirds in our study, and suggested to be efficient in constraining the sperm whales from taking large quantities of catch from the longline. Nevertheless, they could not prevent depredation completely and, at the same time, they reduced catches significantly. Fishermen and longline associations should be encouraged to become active participants in the improvement of existing and the development of new longline designs.
Deep-sea benthic community response to a simulated sedimentation event in two contrasting sites.
1,2, Mayor D.J1, Polymenakou P.N3, Narayanaswamy B.E2, Tselepides A4, Witte U1
1Oceanlab, School of Biological Sciences, University of Aberdeen, Aberdeen, AB41 6AA, Scotland
2Scottish Association for Marine Science, Dunstaffnage Marine Laboratory, Oban, PA37 1QA, UK
3Hellenic Centre for Marine Research, Heraklion, Crete, 71003, Greece
4Department of Maritime Studies, University of Piraeus, 40 Karaoli & Dimitriou st., 185 32 Piraeu, Greece
Phytoplankton, faecal pellets and other organic material, collectively known as phytodetritus, slowly sink into the deep sea and serve as food for a range of organisms. The fate of phytodetritus in deep sea sub-arctic and temperate sediments was investigated in the Faroe-Shetland Channel (FSC) and Eastern Mediterranean (E.Med) by means of 13C pulse-chase experiments. The Faroe–Shetland Channel is considered mesotrophic with bottom water temperature at 0oC or below, while Eastern Medterranean is extremely oligotrophic with bottom water temperature reaching 13oC. This study will provide further insight on the environmental parameters that drive biologically mediated carbon cycling and will enhance our knowledge on short-term carbon remineralization processes in sub-