Dorset Chalk Stream Club December 2013...
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A talk given to the Dorset Chalk Stream Club at the West Stafford Village Hall on the 20th December 2013. The talk is an overview of salmon data collected by the GWCT on the river Frome, Dorset.
Salmon Research at GWCT Anton Ibbotson Bill Beaumont Luke Scott Dylan Roberts Rasmus Lauridsen Stephen Gregory
40 years (!) salmon counting Longest run of salmon count data in Europe Frome record - breaking chalk stream
40 years (!) salmon counting Longest run of salmon count data in Europe 11 years individual salmon data Most instrumented chalk stream in Europe Frome record - breaking chalk stream
40 years (!) salmon counting Returning adult counts: 1973 2013 = 40 years! Data gives us: Spawning stock estimate Index of population trends
2012 a sombre record
2012 a sombre record
2012 a sombre record
2012 a sombre record
Project MorFish Aim: to derive 40 years of statistically defensible adult estimates Analysis to account for: Floods and droughts Power cuts Changes in data collection
40 years (!) salmon counting Data gives us: Migration timing Salmon lengths
Hourly movement pattern Oct 2007
Hourly movement pattern Oct 2011
Daily migration pattern
Project MorFish Aim: to understand drivers of changes in salmon abundance over time Analysis to account for: Flow Temperature Freshwater and marine survival
11 years individual salmon data PIT tagged salmon: 2002 2013 = 11 years
PIT tagging
Frome PIT reader system
Frome PIT reader system
Frome PIT reader system
East Stoke A = Fluvarium reader B = Millstream reader C = Main river reader D = Bindon Mill readers
11 years individual salmon data PIT tagged salmon: 2002 2013 = 11 years Data gives us: Precise smolt population estimates Index of parr population trends
Salmon parr population estimates
Salmon smolt population estimates
11 years individual salmon data Data gives us: Migration timing Individual growth and mortality
Smolt migration timing Flow Day or Night
Smolt lengths: 1968 2000
Smolt lengths: 2006 2013
Summary Frome is internationally important chalk stream Internationally important salmon datasets
1 2 3 4 5 6 7 8 (Frome) 9
Summary Frome is internationally important chalk stream Internationally important salmon datasets Big plans for 2014!
Merry Christmas From the GWCT & INRA http :// www.gwct.org.uk/salmonreport Stephen Gregory e: sgregory@gwct.org.uk
