Radioisotopes Demonstrate the Contrasting Bioaccumulation Capacities of Heavy Metals in Embryonic Stages of Cephalopod Species

Thomas Lacoue-Labarthe,Claude Rouleau,Ross Jeffree,François Oberhänsli,Jean-Louis Teyssié,Roger Villanueva,Paco Bustamante,Dirk Steinke

doi:10.1371/journal.pone.0027653

Abstract

Cephalopods play a key role in many marine trophic food webs and also constitute alternative fishery resources in the context of the ongoing decline in finfish stocks. Most coastal cephalopod species of commercial importance migrate into shallow waters during the breeding season to lay their eggs, and are consequently subjected to coastal contamination. Eggs of common cuttlefish Sepia officinalis, European squid Loligo vulgaris, common octopus Octopus vulgaris and the sepiolid Rossia macrosoma were exposed during embryonic development to dissolved 110mAg, 109Cd, 60Co, 54Mn and 65Zn in order to determine their metal accumulation efficiencies and distribution among different egg compartments. Cuttlefish eggs, in which hard shells enclose the embryos, showed the lowest concentration factor (CF) values despite a longer duration of exposure. In contrast, octopus eggs, which are only protected by the chorionic membrane, accumulated the most metal. Uptake appears to be linked to the selective retention properties of the egg envelopes with respect to each element. The study also demonstrated that the octopus embryo accumulated 110mAg directly from the dissolved phase and also indirectly through assimilation of the contaminated yolk. These results raise questions regarding the potential contrasting vulnerability of early life stages of cephalopods to the metallic contamination of coastal waters.

Highlights

Cephalopods in European waters have attracted increasing attention from marine biologists and fishery scientists [1]
The European squid Loligo vulgaris, the common octopus Octopus vulgaris and the common cuttlefish Sepia officinalis are the main targets of these fishery activities in Europe [1]
Many studies have shown that cephalopods have the capacity to accumulate trace elements at high levels in their tissues [20,21,22,23,24,25,26,27,28]

Summary

Introduction

Cephalopods in European waters have attracted increasing attention from marine biologists and fishery scientists [1]. This group is of high ecological significance for the understanding of the food webs in marine ecosystems. The European squid Loligo vulgaris, the common octopus Octopus vulgaris and the common cuttlefish Sepia officinalis are the main targets of these fishery activities in Europe [1]. For these reasons, an increasing number of studies has focused on their biology, ecology and their responses to the environmental factors that drive their population dynamics

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Results