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| Name |
Ms. Andrea Florella Ribeiro Franco |
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| Thesis title |
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| Modelling shirmp population dynamics: Application to Maputo Bay, Mozambique |
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| Thesis supervisor |
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Prof. João Gomes Ferreira |
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| Thesis abstract |
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| Penaei shirmp assume a grat economic importance worldwide since they make up a significant proportion of the total world shirm catch and due to their suitability for aquaculture. In Mozambique an economically important shallow-water shirmp dishery exists and penaeid shirmp are the most abundant group in the catches, contributing with 23-32% of the total fishery landings by weight.
Im Maputo Bay, southern Mozambique, O. indicus is one of the most important shallow-watter penaeid species, representing a significant fraction of the total bay shirmp catch.
The migration of the P. indicus postlarve occus from October to December. The postlarvae enter eith incoming high tide and settle in the mangrove forest. After the period of grow in the nursery area, juveniles recruit to the bay from April to July and stay approximately one year in the fishery.
An individual growth model was developed and it reproduced the typical growth curve of a penaeid and quantified the duration of each stage: approximately two months for the jevenile and subadult stage and close to one year for the adult atage. The model provides the quantification od different physiological processes involved in growth, which could be used for aquaculture in terms of feed and wastewater management.
Shirmp population dynamics was simulated through a biogeochemical model for individual growth coupled with a demographic model, both of which integrated in a large-scale ecosystem model.
The results od the population model showed that shirmp density decreases from the juvenile stage to the sdult stage and the peaks were obtained near March for the juvenile stage and near April and June for the subadult and sdult stages, respectively. The greater biomasses per unit area also were observed during the first six months of each year and the results are the dominant class.
The model could assist the management of the local fishery by evaluating areas of higher shirmp density as well as periods when shirmp are more abundant, information yhat is important to manage the resource. The simulation of different development scenarios and the analysis of their impact on the shirmp population also provide a basis for testing the opyions that give better results in order to maintain a sustainable fishery. |
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| Thesis website |
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| Not available |
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| Date completed |
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January 2006 |
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