Mid-Atlantic elasmobranchs: Suitable metal scouts?

Heavy metals are a hazard to marine fauna and human health. In this study we assess stable isotopes and metal content in Prionace glauca and Isurus oxyrinchus and analyse these results within and among other species and across regions and geographical areas. Also, we evaluate their suitability, together with Raja clavata and Galeorhinus galeus, as Mid-Atlantic bioindicators.

Bioaccumulation of metals and PCBs in Raja clavata.

The goal of this study was to assess stable isotopes profiles, metals concentration and PCBs in Raja clavata muscle and liver, according to sex and size, and to elucidate its suitability as a Mid-Atlantic biomonitor. The results reflected bioaccumulation and suggested biomagnification processes for As and Hg in muscle tissue. Cd, Cu and Zn were detected in high amounts in liver, Cr, Mn and Rb were relatively stable and low, Pb was not detected and Sr was present in muscle at high levels, decreasing with length.

Genetic and morphometric diversity of the goldcrest (Regulus regulus) populations in the Azores.

We studied the genetic diversity and phylogeography of the goldcrest Regulus regulus from the archipelago of the Azores (North Atlantic Ocean) based on sequences of two mitochondrial genes (cytochrome b and the NADH dehydrogenase subunit 2) and one nuclear gene in the Z-chromosome (intron 9 of the aconitase 1) from 69 individuals, and 41 birds from the Canary Islands and continental Europe for outgroup comparison. To understand the level of concordance between the genetic data and possible morphometric variability, 197 adult living birds from the seven Azorean islands where the species breeds were analysed in terms of eight morphometric characters. Our results are in accordance with previous studies, indicating a recent expansion of goldcrests throughout the archipelago and a low divergence in relation to continental Europe.

Trophic ecology and bioindicator potential of the North Atlantic tope shark.

Sharks are top marine predators vital in maintaining ecosystem health and food web structure. In order to assess tope shark (Galeorhinus galeus) trophic ecology, stable isotope ratios and trace metal concentrations in muscle tissue were determined, according to size and gender, for 124 individuals caught within the Mid-Atlantic region. Data was complemented and analysed according to previous stomach content information and compared with studies performed in the North East Atlantic.