operational fish larval drift modelling bjørn Ådlandsvik og frode vikebø institute of marine...
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Operational fish larval drift modelling
Bjørn Ådlandsvik og Frode VikebøInstitute of Marine Research
Opnet meeting, Geilo, 14-15 May 2008
Why larval drift modelling
Study recruitment processes in fish stocks Prediction Effects of climate variability
Basis for biological Individual Based Models Larval behaviour in the vertical Growth Survival
Why operational
Fish eggs and larvae are vulnerable to oil spill accidents A year class of a major fish stock is worth GNOKs
Useful information for fish larval surveys Useful information for sea bird research ...
How?
Particle tracking Lagrangian Advection and Diffusion model, LADIM
Start from knowledge of typical spawning areas Include simple Individual Based Model
Vertical movement Temperature dependent growth
Operational requirement
Consistency requirement for oil spill overlap analysis:
Fish larvae and oil transport must be forced from the same regional ocean circulation model Otherwise exposure will be controlled by different
current patterns
Difference from oil drift models
Oil drift: Usually know initial condition
time and location of oil spill Larval drift:
Knowledge of typical spawning areas and times Longer simulation time Can be reinitialized if more information becomes
available
Practical implementation
Daily download operational ocean model forecast (Nordic4km) from met.no to IMR
Append to a current and hydrographic archive Rerun the offline larval drift simulation from
spawning/hatching Make plots and put the results on a web site
Presently: http://www.imr.no/~bjorn/oplarve
Cod from Møre
Cod from Moskenesgrunnen
Cod from Malangsgrunnen
Total cod larvae distribution
Total herring larvae distribution
Vertical behaviour for herring larvae Day: 5-20 m, Night:
20-40 m Vertical swimming
speed up to 1/6 bodylength per second
Combination of a deterministic and a random component
To do
Improve the design of the web site Now home made, get help from info dep.
Give the web site a more prominent (and permanent) URL at www.imr.no
Implement larval drift into operational model suite at met.no 24/7 operational organization More frequent updates of current forcing
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