Early development and metabolic rate of the sea louse Caligus rogercresseyi under different scenarios of temperature and pCO2

Abstract

Anthropogenic CO₂ emissions have led to ocean acidification and a rise in the temperature. The present study evaluates the effects of temperature (10, 15 and 20 °C) and pCO₂ (400 and 1200 μatm) on the early development and oxygen consumption rate (OCR) of the sea louse Caligus rogercresseyi. Only temperature has an effect on the hatching and development times of nauplius I. But both factors affected the development time of nauplius II (<temperature = longer development time). Copepodid survival time was also affected by temperature and pCO₂, at 10 °C and 400 μatm, survival was 30 and 44% longer than at 15 and 20 °C. OCRs were impacted by temperature but not by pCO₂. In all treatments, OCR was lower for nauplius II than for the copepodid. Our results show the need to further evaluate the effects of a combination of environmental drivers on the performance of C. rogercresseyi, in a changing and uncertain future.

Keywords: Larvae; Ocean acidification; Oxygen consumption; Sea louse; Warming.