Little empirical information is currently available on the potential effects of acidification and/or warming in sharks, but none exist about digestive capabilities under such future conditions. Here, we investigated the impact of both acidification (ΔpH = 0.5) and warming (+4; 30 °C) on the digestive enzyme levels of recently hatched tropical bamboo shark (Chiloscyllium punctatum). Thirty days post-hatching, juvenile sharks revealed a significant increase in pancreatic trypsin levels under warming, but also a significant decrease under acidification, namely a 42 % drop under present-day temperature and 44 % drop under the warming condition. A similar trend was recorded for the alkaline phosphatase activity in shark’s intestine, i.e. the impact of environmental hypercapnia was also quite notorious—a 50 % drop under present-day temperature and 49 % drop under the warming condition. Thus, our present findings suggest that acidification and warming acted antagonistically, leading to similar enzyme activities under present and future conditions. Future directions on this topic of research should point towards the study of other types of sharks, namely pelagic ones with quite higher energetic demands.
Rosa R., Pimentel M., Galan J. G., Baptista M., Lopes V. M., Couto A., Guerreiro M., Sampaio E., Castro J., Santos C., Calado R. & Repolho T., 2016. Marine Biology 163(3):60. Article (subscription required).
