2026-10-08T08:47:29Z https://api.figshare.com/v2/oai

oai:figshare.com:article/33941035 2026-09-19T00:28:15Z category_24427 item_type_3 month_year_09_2026

Data for "Arctic Greenland cod (<i>Gadus ogac</i>) display marked seasonal plasticity of cardiac heat tolerance but not of chronotropic adrenergic scope for heart rate" Emily Williams (20608880) Animal physiology - systems Arctic fish Cardiac function Adrenaline Heart rate Thermal acclimation Thermal tolerance <p dir="ltr">Polar marine fishes experience prolonged periods of sub-zero temperatures that challenge critical physiological systems, including the heart. In contrast to the Antarctic, Arctic marine fishes also commonly experience large seasonal temperature swings. Here, we caught wild adult Greenland cod (<i>Gadus ogac</i>) in winter (sub-zero) and summer (>6°C) to determine how they seasonally adjust the temperature sensitivity and adrenergic control of their heart rate in relation to seasonal thermal habitat use. Acoustic telemetry revealed that Greenland cod typically occupy shallow depths year-round (IQR: 3.3-7.0m), resulting in stable sub-zero body temperatures overwinter (IQR: -0.52 to -1.4°C) and warmer temperatures in summer (IQR: 3 to 5.5°C). Intrinsic (<i>f</i>_Hint) and maximum (<i>f</i>_Hmax) heart rates were assessed in anaesthetized cod during acute warming, revealing little adrenergic scope for heart rate (using sotalol or isoproterenol), except at warmer tempeatures in late winter. Compared with summer acclimatized fish, winter acclimatized cod had lower heart rates (<i>f</i>_H) at cold temperatures, a limited increase in <i>f</i>_Hduring warming, and markedly reduced cardiac heat tolerance (temperatures at peak <i>f</i>_Hand cardiac arrhythmia). These seasonal differences were associated with prolonged QT intervals in winter, changes in PR and QRS intervals, and a shift in the types of cardiac arrhythmias observed at high temperatures, suggesting electrical remodeling and a potential seasonal change in the electrical mechanisms underlying heat induced heart failure. This pronounced cardiac plasticity likely helps Greenland cod cope with strong thermal variation accross seasons and may help shape their potential reduced sensitivity to longer-term environmental change.</p> 2026-09-19T00:28:15Z Dataset Dataset 10.6084/m9.figshare.33941035.v1 https://figshare.com/articles/dataset/Data_for_Arctic_Greenland_cod_i_Gadus_ogac_i_display_marked_seasonal_plasticity_of_cardiac_heat_tolerance_but_not_of_chronotropic_adrenergic_scope_for_heart_rate_/33941035 CC BY 4.0