SS1.09 Fisheries Population Linkage Spatial and Temporal Variation in Zooplankton
Date: Wednesday, June 12, 2002
Time: 10:30:00 AM
Location: Carson C
 
ScottBE, University of Aberdeen , Aberdeen, United Kingdom, b.e.scott@abdn.ac.uk
Sharples, J, , University of Southampton, School of Ocean and Earth Science,  Southampton, United Kingdom, js1@soc.soton.ac.uk
Ross, O, , University of Southampton, School of Ocean and Earth Science, Southampton, United Kingdom, onr@soc.soton.ac.uk
Wanless, S, , Centre for Ecology and Hydrography,  Banchory, United Kingdom, swanl@ceh.ac.uk
Daunt, F, , Centre for Ecology and Hydrography, Banchory,  Banchory, United Kingdom, Frada@ceh.ac.uk
Greenstreet, S, , Fisheries Research Services, Abderdeen, United Kingdom, greenstreet@marlab.ac.uk
Fraser, H, , Fisheries Research Services, Aberdeen, United Kingdom, fraserh@marlab.ac.uk
 
THE USE OF BIO-PHYISCAL INDICES TO LINK CHANGES IN THE AVAILABLITY OF FISH TO PREDATORS.
image
In the North Sea, sandeels are the major prey for top-predators such as seabirds and marine mammals as well as being the largest single industrial fishery. Attempts to define a level of sustainable fisheries have not been conclusive on the impact of industrial sandeel fisheries on seabirds, perhaps because emphasis has been on sandeel abundance rather than the availability of sandeels to seabirds. Availability of fish is a consequence of the longer term, such as the interaction of the bio-physical environment with critical life history events that drive growth and survival rates of individuals and ultimately determine the population dynamics. Availability is also the consequence of the short term with daily, even hourly events in the physical environment driving the degree of aggregation and proximity to potential predators. Within an interdisciplinary team, we use seasonal indices produced from a 1-D vertical coupled physical-biological numerical model to determine whether variability in oceanographic features such as the timing of the onset, breakdown of stratification and total primary production can influence sandeel population characteristics such as size at age and emergence patterns. Also using daily modelled indices such as mixed-layer depth and pycnocline gradient and comparing these with the foraging locations, depth, timing and success of specially tagged birds, we will determine if these physical properties can be causative in controlling fish availability to predators.