US EPA

2480065 

Journal Article 

Trophic ecology and bioindicator potential of the North Atlantic tope shark 

Torres, P; da Cunha, RT; Maia, R; Rodrigues, A 

2014 

1 

Science of the Total Environment
ISSN: 0048-9697
EISSN: 1879-1026 

ELSEVIER 

AMSTERDAM 

481 

574-581 

English 

24631620 

10.1016/j.scitotenv.2014.02.091 

WOS:000335096400063 

http://://BCI:BCI201400422901
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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. Our results revealed that tope sharks fed at a low trophic level and within a more pelagic-based food web when compared with other North Atlantic regions. MixSIR application reflected its piscivorous diet and study area topography, oligotrophic waters and volcanic nature, suggesting the occurrence of a Mid-Atlantic tope shark population. Considering a non-anthropogenic volcanic source for observed metal contents, the results reflect bioaccumulation and suggest biomagnification processes for As and Hg. These metals exceeded legislated maximum limits for some countries with a maximum of 28.98 +/- 1.26 and 0.57 +/- 0.01 mg kg(-1) wet weight, respectively, increasing significantly with size for both males and females, Conversely, Cr, Rb and Zn were relatively stable while Cd and Pb were not detected. Hg and Se were strongly correlated, suggesting a Se toxicity mitigation role. Given the tope shark travel capacity and the results obtained, the species may be used as a Mid-Atlantic bioindicator of environmental quality. (C) 2014 Elsevier B.V. All rights reserved. 

Stable isotopes; Trace metals; Bioaccumulation; Galeorhinus galeus; Mid-Atlantic