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