Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2019

Erindi/veggspjald / Talk/poster E71

Stable oxygen isotope reconstruction of ambient temperature of the Icelandic cod (Gadus morhua) stock over the last 100 years

Höfundar / Authors: Gotje von Leesen (1), Ulysses Ninnemann (2), Ásta Guðmundsdóttir (3) and Steven E. Campana (1)

Starfsvettvangur / Affiliations: 1. University of Iceland, 2. University of Bergen and Bjerknes Centre for Climate Research, 3. Marine and Freshwater Research Institute

Kynnir / Presenter: Gotje von Leesen

Increasing water temperatures are predicted around the globe with high amplitudes of warming in Subarctic and Arctic regions where Atlantic cod (Gadus morhua) populations currently flourish. To determine if cod will move or migrate to avoid increasing water temperatures, we have reconstructed oxygen isotope and temperature chronologies from otoliths of one of the largest cod stocks in the world. Samples of the last 100 years were collected reflecting the environmental conditions of the Icelandic waters. For δ18O otolith analysis, individual annual growth increments from immature and mature stages were micromilled from adult otoliths. Reconstructed temperature time series based on δ18O otolith showed differences in temperature exposure and association between immature and mature cod. Linear mixed effect models confirmed that stable oxygen isotope time series are significantly different between both life stages. Overall, cod otolith δ18O was significantly correlated with water temperature. But does that mean that cod are going to passively remain where they are as the global oceans warm?