A millennium of north-east Atlantic cod juvenile growth trajectories inferred from archaeological otoliths.

Guðbjörg Ásta Ólafsdóttir,Ragnar Edvardsson,Hlynur Bárðarson,Gróa Pétursdóttir,Aldo Corriero

doi:10.1371/journal.pone.0187134

Guðbjörg Ásta Ólafsdóttir, Ragnar Edvardsson + Show 3 more

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https://doi.org/10.1371/journal.pone.0187134

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Abstract

Archaeological excavations of historical fishing sites across the North Atlantic have recovered high quantities of Atlantic cod (Gadus morhua) bones. In the current study we use Atlantic cod otoliths from archaeological excavations of a historical fishing sites in north-west Iceland, dated to AD 970 –AD 1910 to examine historical growth trajectories of cod. No large scale growth variations or shifts in growth patterns were observed in the current chronologies, supporting the stability of historical Atlantic cod growth trajectories. The most significant variation in growth patterns was consistent with those that have been observed in recent times, for example, reduced early juvenile growth during periods of colder ocean temperature. The current results represent a high resolution chronological record of north-east Atlantic cod growth, greatly increasing the prior temporal range of such data, thereby providing a valuable baseline for a broad range of studies on Atlantic cod growth.

Highlights

Historical baselines of ecological states can improve the interpretation of current anthropogenically induced change
A calcified structure in the inner ear of fish, are occasionally recovered during archaeological excavations [9]. They are unique among zoo-archaeological material in that they simultaneously convey information on individual fish age [10], growth [11] and reflect the environmental conditions that the fish encountered throughout life-history [12,13,14]
During the post excavation work all identifiable bones were identified to a species level and all Atlantic cod otoliths were removed from the bone assemblage for further analysis

Summary

Introduction

Historical baselines of ecological states can improve the interpretation of current anthropogenically induced change. Such baselines have already shown their value as a guide to modern day management and conservation [1]. A calcified structure in the inner ear of fish, are occasionally recovered during archaeological excavations [9]. They are unique among zoo-archaeological material in that they simultaneously convey information on individual fish age [10], growth [11] and reflect the environmental conditions that the fish encountered throughout life-history [12,13,14].

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