Measuring species concentration, diversification and dependency in a macro-fishery

This paper studies the triad “concentration, diversification and dominance” in an ecosystem \((\Omega _{t})\) defined as the macro-fishery comprised by the entire commercial fish species landed in a specific geographical area and time horizon (1986:1–2011:12). This is faced computing alternative monthly concentration indices (CIs) based on the income shares of individual species and, afterwards, analysing the structural features and overall dynamics of the monthly time series related to each of the CIs. Special attention will be paid on categorising not only the long-term cycles, but also the seasonal components found in the series.