Commercially relevant species in the Mediterranean Sea: a perspective from Late Pleistocene to the Industrial Revolution

The Mediterranean Sea is the world's second-largest biodiversity hotspot and has been impacted by several environmental changes and human activities since pre-historic times. We present the results of a systematic review of the published literature on the nature and extent of these impacts on the ancient-historic Mediterranean marine ecosystems. We aim to provide an overview of the current state of knowledge and identify research gaps about climate and human-activity impacts on commercially relevant species of marine mammals, fishes, and molluscs in the Mediterranean Sea over the last 130 thousand years until the Industrial Revolution (the year 1850). In most of the reviewed publications, species were used as indicators of past climatic conditions or human subsistence strategies. A research gap remains, however, in quantifying their effects on marine ecosystems. Based on our results, we identify data trends in time and space and by functional group. Data are available primarily from the Holocene rather than the Late Pleistocene, reflecting a heterogeneous availability of records. The Adriatic Sea is underrepresented among subregions, which may indicate variability of accessible data between subregions rather than an actual lack of information. Marine mammals were less studied than fishes and molluscs in the three subregions. Despite the lack of standardised guidelines to conduct studies and the subsequent variability in information, this work can provide novel insights into the importance of studying the evolution of research focused on past environmental and anthropogenic impacts in the Mediterranean Sea. Research efforts need to be balanced to examine both economically and ecologically valuable species in the marine ecosystem. We also reinforce the need for uniforming approaches to gather data in a useable format for posterior research.