This work reports on the maritime use case development and evaluation of the prototype of the project Big Data Analytics for Time Critical Mobility Forecasting (datAcron), which was funded by the European Union Horizon 2020 programme. datAcron aimed at developing novel methods to detect threats and abnormal activities in streams of large number of moving objects in wide maritime and aerial areas. The datAcron maritime use cases, which were scoped in the Maritime Work Package (WP5), geared on fishing activities monitoring, aligning with the European Union Maritime Security Strategy. The maritime use cases aimed at providing research partners with maritime domain knowledge to frame in some operational context novel approaches designed during the project. Moreover, the maritime use cases provided a basis for the datAcron maritime prototype setup and evaluation of big data solutions. Six scenarios falling under three use cases were therefore developed, identifying relevant data sources, situational indicators as well as corresponding operational tasks. This paper overviews the design, development and evaluation of the datAcron maritime use case.