Cephalopod beak sections used to trace mercury levels throughout the life of cephalopods: The giant warty squid Moroteuthopsis longimana as a case study

• Published in: Marine environmental research 2020-10, Vol.161, p.105049-105049, Article 105049
• Main Authors: Queirós, José P., Bustamante, Paco, Cherel, Yves, Coelho, João P., Seco, José, Roberts, Jim, Pereira, Eduarda, Xavier, José C.
• Format: Article
• Language: English
• Subjects: Animal biology; Beak; Beaks; Bioaccumulation; Biodiversity and Ecology; Cephalopods; Ecotoxicology; Environmental Sciences; Food chains; Food webs; Invertebrate Zoology; Juveniles; Life Sciences; Marine molluscs; Mercury; Mercury (metal); Ontogenetic shifts; Predators; Prey; Rostrum; Southern ocean; Squid; Toxicology; Trace elements
• ISSN: 0141-1136; 1879-0291
• DOI: 10.1016/j.marenvres.2020.105049

Cephalopods represent an important pathway for mercury transfer through food webs. Due to the general difficulties in capturing oceanic squid, beaks found in the diet of top predators can be used to study their life-cycles and ecological role. Using upper beaks of the giant warty squid Moroteuthopsis longimana (major prey in the Southern Ocean), we describe a method to assess mercury concentrations along the life of cephalopods through the segmentary analysis of beak sections (i.e. tip of the rostrum and subsections along the hood). Distinct total mercury concentrations in the different subsections support that beaks can be used to study mercury levels in different periods of cephalopods' life-cycle. Mercury values in the anterior (1.3–7.9 μg kg−1 dw) and posterior (7.8–12.5 μg kg−1 dw) subsections of the hood reflect juvenile and adult stages, respectively. Furthermore, these results confirm that mercury bioaccumulates continuously throughout the individuals' life, with adults doubling their mercury concentrations to juveniles. •Cephalopod beaks can be used to study mercury exposure throughout individuals' life.•Anterior section of the hood reflects juvenile levels and the posterior the adult.•Adults of Moroteuthopsis longimana are twice more exposed to mercury than juveniles.•Mercury in M. longimana increase with squid size and trophic position.