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LIFECO - linking hydrography, ecosystem dynamics and fish recruitment |
| LIFECO (LInking hydrographic Frontal activity to ECOsystem activity) is a international, multidisciplinary research project set up to resolve the influence of hydrographic fronts on the recruitment success of North Sea fish stocks. It is carried out during the period 2001-2003 and integrates results from an extensive field program, a 3-D coupled bio-physical model, remote sensing data and selected data from historic databases. |
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In
the project we combine
various sources of remote sensing to produce the best possible description of surface frontal features. We plan to combine information (data fusion) from sea surface temperature, ocean colour, radar altimetry and synthetic aperture radar (SAR), which again is combined and compared with the surface information obtained during our cruises. In focus is the chlorophyll-a concentration estimates from the satellite ocean colour, which is indicative of enhanced primary productivity and possibly frontal zones. |
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Example
of a frontal evolution:
How
do fronts evolve? This is an animation made by PJS Franks of the
evolution of the phytoplankton and temperature in a front at mixed-layer
depth. Evolve over 20 days, with 2 wind events, Ekman flux to cold side
of front. (click on picture to see animation) |
| One of the important targets of the investigation are the larval stages of fish. The mortality in the larval stage is extensive, and the variable mortality determines the recruitment of new “recruits” to the adult, fishable, stock. While fish larvae are often concentrated in the immediate frontal zone, the characteristics of – and variation in – the frontal zone, are suspected to exert a fundamental influence on the larval life and the chances of survival. |
Integration of data is provided by an extensive
GIS-analysis where we test for linkages between the ecosystem dynamics and
specific frontal processes. Furthermore, the program aims at resolving the
influence of hydrography on spatial distribution and feeding interactions of
commercial fish stocks, results that will be of great importance for
assessment and management strategies. Specifically the project will aid in the
development of management strategies based on environmentally sensitive areas,
supporting the key information on major ecological enclaves. (read more about
our workplan)
Contour plot of salinity
The
cruise programme involves several research vessels from Danish and German
research institutes. We cover the North Sea east of 3°E
with a series of transects crossing the hydrographical fronts. Our sampling
include temperature, salinity, oxygen, light and fluorescence profiling,
measurements of primary and secondary productivity and sampling for micro-,
meso- and macro-zooplankton, fish larvae, juveniles and adults. Along most of
our cruise tacks we also continuously measure surface physical characteristics,
current pattern and acoustical backscatter. Cruises are carried out with
approximately monthly intervals from Marts to November 2001. (see cruise
programme)
