Comparative effects of two temperatures (0 & 3 °C) on Polar cod embryonic and larval development

Abstract

Polar cod (Boreogadus saida) are particularly vulnerable to climate change. Increasing our knowledge of polar cod development will help improve our understanding of the impact of climate change and the impacts this might have on the population. This study aimed at characterizing the development of Polar cod from fertilisation to 86 days post fertilisation (dpf) at two temperatures within their biological tolerance (0 & 3 °C) in order to determine the thermal response during early life histories. Adult polar cod were wild caught from Svalbard waters, stripped and artificially fertilised. The present study found that the larvae incubated at 0 °C experienced less mortality, greater hatching success and a larger size at hatch and during early feeding than 3 °C larvae. However the larvae had a slower feeding initiation, a lower feeding success. In regards to the results of this study 0 °C treatment provided the ideal conditions for survival. However polar cod early life development might benefit from a slightly warmer Arctic from faster development leading to less time spent as vulnerable larvae resulting in better juvenile recruitment. However under accelerated temperatures the temperature optimum may be exceeded and larvae will experience significantly negative biological and environmental consequences.