To breed or not to breed: endocrine response to mercury contamination by an Arctic seabird

• Published in: Biology Letters
• Main Authors: Tartu, Sabrina, Goutte, Aurélie, Bustamante, Paco, Angelier, Frédéric, Moe, Borge, Clément-Chastel, Céline, Bech, Claus, Gabrielsen, Geir Wing, Bustnes, J. O., Chastel, Olivier
• Other Authors: Centre d'Études Biologiques de Chizé (CEBC), Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Division of Arctic Ecology (NINA), Norwegian Institute for Nature Research (NINA), Department of Biology Trondheim (IBI NTNU), Norwegian University of Science and Technology Trondheim (NTNU), Norwegian University of Science and Technology (NTNU)-Norwegian University of Science and Technology (NTNU), Norvegian Polar Research Institute (NPRI), Norwegian Polar Institute
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2013
• Subjects: intermittent breeding; mercury; GnRH challenge; luteinizing hormone; black-legged kittiwake; [SDE]Environmental Sciences; Arctic; Svalbard; Black-legged Kittiwake; rissa tridactyla
• Online Access: https://hal.science/hal-00828084; https://doi.org/10.1098/rsbl.2013.0317

International audience Mercury, a ubiquitous toxic element, is known to alter expression of sex steroids and to impair reproduction across vertebrates but the mechanisms underlying these effects are not clearly identified. We examined whether contamination by mercury predicts the probability to skip reproduction in black-legged kittiwakes (Rissa tridactyla) from Svalbard. We also manipulated the endocrine system to investigate the mechanism underlying this relationship. During the pre-laying period, we injected exogenous GnRH (gonadotropin-releasing hormone) to test the ability of the pituitary to release luteinizing hormone (LH, a key hormone for the release of sex steroids and hence breeding) in relation to mercury burden. Birds that skipped reproduction had significantly higher mercury concentration in blood than breeders. Endocrine profiles of these birds also varied based on breeding status (breeders versus non-breeders), mercury contamination and sex. Specifically, in skippers (birds that did not breed), baseline LH decreasedwith increasingmercury concentration inmales,whereas it increased in females. GnRH-induced LH levels increased with increasing mercury concentration in both sexes. These results suggest that mercury contamination may disrupt GnRH input to the pituitary. Thus, high mercury concentration could affect the ability of long-lived birds to modulate their reproductive effort (skipping or breeding) according to ongoing environmental changes in the Arctic, thereby impacting population dynamics.