HR: 1340h
AN: H53B-1231    [Abstracts]
TI: Are Landscape Hierarchies of Groundwater-Surface Water Exchange Patterning Important in Spawning Site Selection by Atlantic Salmon (Salmo salar L.,)?
AU: * Grant, J D
EM: j.grant@abdn.ac.uk
AF: Environmental Hydrology Research Group, Department of Geography University of Aberdeen, Aberdeen, AB24 3UF, United Kingdom
AU: Soulsby, C
EM: c.soulsby@abdn.ac.uk
AF: Environmental Hydrology Research Group, Department of Geography University of Aberdeen, Aberdeen, AB24 3UF, United Kingdom
AU: Malcolm, I A
EM: i.a.malcolm@marlab.ac.uk
AF: Fisheries Research Services, Freshwater Laboratory Faskally, Pitlochry, PH16 5LB, United Kingdom
AU: Gibbins, C
EM: c.gibbins@abdn.ac.uk
AF: Environmental Hydrology Research Group, Department of Geography University of Aberdeen, Aberdeen, AB24 3UF, United Kingdom
AB: The Atlantic salmon's (Salmo salar L.,) native Scottish, headwater spawning grounds, can be viewed as dynamic hot spots of biological productivity set within a hierarchical landscape sculpted by complex physico-chemical processes. Traditionally controls on female spawning site selection, have mainly been attributed to the sedimentary and hydraulic characteristics of available spawning habitat. In the UK, the influence of physico-chemical landscape hierarchies on spawning site selection is poorly understood. This study aims to provide a preliminary insight into the importance stream hydrochemistry has at different hierarchical scales, on spawning site selection by Atlantic salmon in a Scottish braided river system. During the 2005 and 2006 spawning seasons, intensive surveys of dissolved oxygen, alkalinity, trace metals and continuous temperature monitoring were undertaken under high and low flow conditions, in the surface water network of the floodplain reaches. Using GPS data within a GIS framework, these data were related to the locations utilised by spawning fish surveyed on a daily basis in each year. Results indicated that patterns of groundwater – surface water exchange were spatially and temporally dynamic, occurring at a range of scales across the channel floodplain system. A hierarchy of channel types could be differentiated on the basis of contrasting surface water quality and source water characteristics. These included channels dominated by soures such as groundwater, hillslope drainage and main-stem river water. Although most channels contained good hydraulic and sedimentary conditions, spawning was concentrated in those locations which displayed strong chemical groundwater signatures. In 2005: 64 % and 2006: 44 % spawning occurred in groundwater channel types. This study suggests that GW-SW interaction hierarchies may play an important role in determining site selection by spawning Atlantic salmon and sea trout.
DE: 1830 Groundwater/surface water interaction
SC: Hydrology [H]
MN: 2007 Fall Meeting