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Observing temporal processes in an ecosystem hotspot over
an annual cycle with high resolution acoustic
byOlav Rune Godø*, Espen Johnsen*, Gavin
Macaulay*, Ruben Patel**, Terje Torkelsen**
* **
Background and motivation• Ecosystem approach needs knowledge
on processes• They occur in time and space
independent of survey time• Vessel based surveys are vulnerable to
time shifts in processes among years• They are impacted by surface blind
zone
Objectives
• Demonstrate performance and potential of observatory techniques
• Identify important events in ecosystem seasonal dynamics
• Identify and assess scaling and timing of biological processes
• Identify and quantify factors of importance to survey performancehttp://love.statoil.com
Methods
• LoVe Observatory in operation since September 2013
• Use data from vertical echosouder (70 kHz)• Backscattering • Acoustic target strength and tracking• Wind data from near by land station• Groundtruthing through vessel observations
http://love.statoil.com
Results
• We can observe:– Ecosystem dynamics over an annual cycle– Time and character of specific ecosystem
component events– Impacts of environment and ecosystem on
performance of scientific surveys– Stock dynamics over their spawning
season
Story 1: Ecosystem dynamics
9 days period
Oct 2013 Nov Dec Jan 2014 Feb Mar Apr May Jun
Story 2: Timing of processes
Spring bloom starts when cod emigrate
25 March
Cod
Spring bloom
May 4
Story 2 (cont): Timing of processes – cod
Feb
May
Story 2 (cont): Timing of processes– cod
Surface
De
pth
(1
40
of
265
m)
Jan 31 Time (7:27 – 8:00)
Story 2 - 3: Herring dynamics and survey performance
Story 3: Survey performanceV
ind
sp
eed
(M
/S)
January
Story 4: From individual to collective
• Clumpy dist rel• Resolved dist rel
nssn
nAA /
1
Averaging sA by hour
hourtfishfreq /Where tfish are tracked individuals
freqsrel A /Expresses distance between individuals
Story 4: From individuals to collective
Feb
MayFeb 1 May1
Migration directionN S
Do ”rel” tell us something about
the spawning process?
Summary
• Observatory techniques produce unique new information
• We can fulfil objectives – identify ecosystem dynamics, scaling and process
• Factors impacting surveys (wind, fish in surface blind zone) are demonstrated
• Plan to implement a observatory transect.
Thank you for your attention and thanks
to Statoil ASA for their financial and
competence support