Araújo, Júlio N., Mackinson, Steve, Stanford, Richard J., Sims, David W., Southward, Alan J., Hawkins, Stephen J., Ellis, Jim R. and Hart, Paul J.B.
Modelling food web interactions, variation in plankton production, and fisheries in the western English Channel ecosystem
Marine Ecology Progress Series, 309, . (doi:10.3354/meps).
Full text not available from this repository.
To explore the contributions that fishing, trophic interactions and plankton production
make to explanations of the observed variation of higher trophic (principally fish) levels in the
western English Channel ecosystem, Ecosim simulations were run from 1973 to 1999 using the most
complete data set yet assembled. The results indicate that a bottom-up mechanism plays an important
role in the system production. Inclusion of a primary producer biomass forcing term, estimated
from empirical data, improved the goodness of fit of the model estimates to the available biomass data
by about 25% compared to fitting using only the series of fishing mortalities. Model fitting was
further improved by changing the so-called vulnerability parameters, causing an overall improvement
of 62% in explained variation. Incorporating the new vulnerability values, the model was used
to estimate a primary production anomaly function to replace the primary producer biomass forcing
in driving the model simulations. In this scenario, the model estimated a series of values for primary
producer abundance that approximated the empirical data, but gave lower estimates than were
observed towards the end of the period. This version also gave a better fitting to the zooplankton
abundance data and generally improved the fitting to all functional groups.
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