Abstract
Identifying the main spatial distribution patterns of fish species is an important step in the process of learning their spatial occupation strategy and defining spatialized management strategies. This work aims to provide a methodology for the deterministic analysis of the spatiotemporal distribution of the abundance of certain species with a view to its integration into an integrated fisheries management model. This methodology is applied to the fishing dynamics of octopus (Octopus vulgaris, cuvier 1797) in the Mauritanian zone over the last 30 years.In this context, an approach inspired by data analysis factorization methods is developed to reduce a long time series of georeferenced abundance data while ensuring that a satisfactory part of the variance is preserved. This approach has led to the creation of portfolios of cards, symptomatic of each of the two key seasons of octopus dynamics over the past 30 years. During the hot season, which is the main breeding season for the species, the portfolio contains only one map reflecting a clear and stable spatial breeding strategy over time with a concentration of abundance in an area located to the north of the Mauritanian EEZ. On the other hand, during the cold season, the wallet contains four cards indicating greater variability in the strategy of occupying space. These differences in seasonal spatial dynamics are statistically related to very similar dynamics observed in sea surface temperature maps.These results, as well as the information available on the biology and ecology of the species, are coupled with an analysis of the structuring of the octopus operating system to parameterize an integrated model on the ISIS-Fish modeling platform with a view to to be able to test and assess the impacts of different management scenarios. Sketches of management scenarios consisting of reducing fishing effort, determining a binding TAC or extending the duration of fishing closures are tested. If the state of development of the model does not yet allow operational aims, this is clearly the goal of the upcoming consolidation steps, many of which will focus on better modeling of recruitment in relation to the spawning stock and environmental variables not yet present. in the model. The integration of socio-economic considerations and parameters will ultimately make it possible to more concretely assess management scenarios co-constructed with the stakeholders of the Mauritanian fishing system.