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Studies on Optimum Carrying Capacities of Mariculture Systems by Modelling Trophic Interactions

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Relation http://eprints.cmfri.org.in/13380/
 
Title Studies on Optimum Carrying
Capacities of Mariculture
Systems by Modelling Trophic
Interactions
 
Creator David, Neetha Susan
 
Subject Farming/Culture
Mariculture
Trophic Modelling
 
Description An attempt was made to construct trophic models of different aquaculture systems
where shrimp was used as the key species of culture. The three different systems of
culture viz., extensive system of aquaculture (where shrimp was cultured with crabs),
modified extensive system (where shrimp and fish are stocked and fed with
manufactured feed ) and polyculture system ( where shrimp was stocked along with
different types of fish and mussel ) were modeled using the trophic modeling
software ECOPATH. Two scenarios of each system i.e., initial (the day of stocking)
and final (day of harvest) were created to know the ecological changes brought
about by the aquaculture process. The different input requirements of the model
were biomass, production per biomass, consumption per biomass, harvest details
and diet compositions of all the organisms associated with the system. About 11 -
12 ecological groups were created in each system. On mass balancing ecological
information of the species, ecosystem indices and flow indices were obtained. The
results of the model give an overview of the resources found in the pond
simultaneously and reveal the degree of trophic interactions. The ecotrophic
efficiency (EE) of phytoplankton and detritus was very low in all the system showing
that it is very sparsely utilized. Hence energy transfer from lower trophic level
seemed to be very low. The cultured species had a high EE as they were completely
harvested from the system. On comparing the initial and final model it was found that
the final stages of the extensive system and polyculture system of culture was
having better ecosystem stability while the modified extensive system was highly
unstable. The relative ascendancy was high in modified extensive system indicating
its unstable situation. Also the system overhead decreased showing a decrease in
“strength in reserve”. The flow to detritus was found to increase in the modified
extensive system where formulated feed was used. A hypothetical model was
constructed by introducing mussels in the feed aquaculture system. On modeling it
was found that the introduction of mussels could bring about better stability to the
system as there was high variation in the ecosystem indices. Carrying capacity of the
above modeled systems could be calculated and optimum stocking densities of the
cultured species are also given.
 
Date 2009
 
Type Thesis
PeerReviewed
 
Format text
 
Language en
 
Identifier http://eprints.cmfri.org.in/13380/1/Thesis_Neetha%20Susan%20David.pdf
David, Neetha Susan (2009) Studies on Optimum Carrying Capacities of Mariculture Systems by Modelling Trophic Interactions. Doctoral thesis, ICAR - Central Marine Fisheries Research Institute.