1 CIIMAR- Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos, s/n, 4450-208, Matosinhos, Portugal; Biology Department, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007, Porto, Portugal.
2 CIIMAR- Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos, s/n, 4450-208, Matosinhos, Portugal.
3 Department of Biomedical and Clinical Sciences, Faculty of Medicine and Clinical Sciences, Linkoping University, 581 83, Linkoping, Sweden.
4 CIIMAR- Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos, s/n, 4450-208, Matosinhos, Portugal. Electronic address: jalmeida@ciimar.up.pt.