Marine historical ecology of groupers (Epinephelidae) in the eastern Mediterranean utilising zooarchaeology, dietary isotopes, collagen sequencing, and peptide mass fingerprinting

Abstract

Groupers are ecologically and commercially important fishes in the Mediterranean which have been exploited for millennia and heavily overfished in recent decades. Through a multi-methodological approach, we can establish historical ecological baselines and gain long-term perspectives on grouper exploitation. This thesis studies grouper bones from three eastern Mediterranean archaeological sites to reconstruct past catch sizes, investigate past trophic ecology (diet and feeding behaviour), and explore past species distribution and abundance. Catch size reconstruction shows that groupers regularly reached much larger sizes (ca. 150 cm Total Length [TL]) in the past than they do today (average catch sizes 30-60 cm TL), even within protected waters. Locally in Iskenderun Bay, Turkey, groupers were likely overfished by the Hellenistic period. Dietary stable isotopes (δ13C and δ15N) analysis of ancient marine fishes shows greater trophic diversity in the past and less competition for trophic resources than is observed in Levantine coastal ecosystems today. Collagen sequence reconstruction enabled the production of a phylogenetic tree for four Mediterranean grouper species within the Epinephelus genus. Twenty three novel peptide biomarkers were discovered and validated for Mediterranean groupers, demonstrating the potential for intra-genus species level identifications using Zooarchaeology by Mass Spectrometry (ZooMS). Applying these ZooMS markers to a case study demonstrated millenia of white grouper (Epinephelus aeneus) abundance in Iskenderun Bay and showed that the white grouper is capable of growing 30 cm longer than previously documented. This thesis demonstrates the potential of archaeology to inform the marine historical ecology of a key fisheries species in the Mediterranean.