Forgotten Mediterranean calving grounds of grey and North Atlantic right whales: evidence from Roman archaeological records

Abstract

Right whales (Eubalaena glacialis) were extirpated from the eastern North Atlantic by commercial whaling. Grey whales (Eschrichtius robustus) disappeared from the entire North Atlantic in still-mysterious circumstances. Here, we test the hypotheses that both species previously occurred in the Mediterranean Sea, an area not currently considered part of their historical range. We used ancient DNA barcoding and collagen fingerprinting methods to taxonomically identify a rare set of 10 presumed whale bones from Roman and pre-Roman archaeological sites in the Strait of Gibraltar region, plus an additional bone from the Asturian coast. We identified three right whales, and three grey whales, demonstrating that the ranges of both of these species historically encompassed the Gibraltar region, probably including the Mediterranean Sea as calving grounds. Our results significantly extend the known range of the Atlantic grey whale, and suggest that 2000 years ago, right and grey whales were common when compared with other whale species. The disappearance of right and grey whales from the Mediterranean region is likely to have been accompanied by broader ecosystem impacts, including the disappearance of their predators (killer whales) and a reduction in marine primary productivity. The evidence that these two coastal and highly accessible species were present along the shores of the Roman Empire raises the hypothesis that they may have formed the basis of a forgotten whaling industry.

Keywords: Atlantic grey whale; North Atlantic right whale; ancient DNA barcoding; antiquity; collagen fingerprinting (ZooMS); shifting baseline.

Figure 1.

Summary of knowledge on the historical distribution of: (a) the North Atlantic right whale (Eubalaena glacialis), with a focus on records in the Mediterranean Sea and nearby Gibraltar area; and (b) the Atlantic population of the grey whale (Eschrichtius robustus), with current Pacific calving grounds illustrated for reference. Dark red circles correspond to the new archaeological records added by the present study. Details are in the electronic supplementary material, appendix S1. North Atlantic right whale illustration from the National Oceanic and Atmospheric Administration, United States, National Marine Fisheries Service (public domain); grey whale illustration from [16] (public domain). (Online version in colour.)

Figure 2.

Location of the archaeological sites referred to in this study. (a) The location of La Campa de Torres, Asturias (1), and the general location of (b) (box). (b) The location of the four archaeological sites in the Strait of Gibraltar: (2) Baelo Claudia, Tarifa; (3) Iulia Traducta, Algeciras; (4) Septem, Ceuta; and (5) Tamuda, Tetouan. Satellite images from the National Aeronautics and Space Administration World Wind (open source). (Online version in colour.)