Long-term variability in the abundance of a macro-organism could provide fundamental information for evaluating its evolution, its responses to climate changes and human impact, enabling management and preservation strategies. Biological monitoring in aquatic systems has provided evidence of long-term variability in the abundance of macro-organisms. However, almost all such records span less than a century; there are none which span centuries or more. Aquatic bottom sediments have provided records of species abundance on longer time scales, although previous studies addressed marine fish species using fossil remains (mainly fish scales) and reconstructed abundance for only seven fish taxons. Thus, there remains a distinct lack of information on long-term changes in abundance for many marine fish species and other macro-organisms in aquatic systems.