The sub-fossil red coral of Sciacca (Sicily Channel, Mediterranean Sea): colony size and age estimates

Giorgio Bavestrello,Gianluca Quarta,Riccardo Cattaneo-Vietti,Federico Spagnoli,Lucio Calcagnile,Martina Canessa,Marisa D’Elia,Marzia Bo

doi:10.1007/s10347-020-00620-x

Giorgio Bavestrello, Gianluca Quarta + Show 6 more

Open Access

https://doi.org/10.1007/s10347-020-00620-x

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Abstract

The Mediterranean red coral, Corallium rubrum (L.), has been a valuable economic resource for more than 2000 years. The Sicily Channel and surrounding areas are one of the most famous red coral fishing grounds of the whole region, hosting the deepest ever found living colonies and large sub-fossil red coral deposits; the so-called Sciacca banks are a unique location in the whole Mediterranean Sea. In this paper, a morphometric description of this sub-fossil population is presented for the first time from studies of colonies in the collection of several coral factories from Torre del Greco (Naples), with radiocarbon age estimations and growth rate evaluations. From the results of this study, after several thousand years Sciacca red coral colonies maintained the organic matrix structure with evident annual discontinuities, allowing estimations of the annual growth rate (about 0.3 mm/year) and the average population age (about 33.5 years). These resulting data are similar to the values determined for deep-dwelling living red coral populations. The radiocarbon dating evidenced a range of ages, from 8300 to 40 years before 1950 CE, mostly falling between 2700 and 3900 YBP, suggesting that colonies accumulated over a wide span of time. In view of the tectonically active nature of the area, several catastrophic events affected these ancient populations, maintaining them in a persistent state of early-stage, structurally similar to the those in current over-exploited areas.

Highlights

The precious red coral (Corallium rubrum L.) is a longliving, slow-growing colonial octocoral that represents one of the most significant marine species of the Mediterranean Sea, often taking on important anthropological meanings
The available sub-fossil red coral colonies from the Sciacca banks were broken in such a way that, generally, it was not possible to determine the morphology of the whole colony (Fig. 2a)
On the basis of the recorded basal diameters and applying the equations proposed by Mallo et al (2019), the estimated average height was of 8 ± 0.39 cm and the weight resulted in 12.3 ± 0.8 g (Table 1)

Summary

Introduction

The precious red coral (Corallium rubrum L.) is a longliving, slow-growing colonial octocoral that represents one of the most significant marine species of the Mediterranean Sea, often taking on important anthropological meanings. This species produces an workable axial skeleton (Vielzeuf et al 2008), composed of high-magnesiumcalcite, which has been a valuable economic resource for Mediterranean fishermen for more than 2000 years (Tsounis et al 2010; Cattaneo-Vietti and Bavestrello 2010; Cattaneo-Vietti et al 2016). The deeper ones (the main target of harvesting today)

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Conclusion