Effects of temperature and oxygen availability on erythrocyte and leucocytes of Halobatrachus didactylus

JUAN MANUEL MOLINA; PEDRO GUERREIRO; ANDREAS KUNZMANN

Bremen

Conferencia; ZMT Annual Conference (ZAC3); 2022

ZMT

Temperature and oxygen are two of the most affected environmental variables in our age of climate. The changes in these variables can have a plethora of effects on marine biota, and understanding them is of outmost importance to address this issue. We simulated climate change scenarios, to evaluate the effects of high temperature, hypoxia and a combination of both, on the blood cell proportions and shape of Hallobatrachus dactylopterus. We used a condition index to estimate the welfare of the fish in each treatment. The two environmental drivers studied showed effects on the number of white blood cells and shape of red blood cells over the course of 30 days of exposure. The most affected parameter was the red and white blood cell count, which increased significantly in hypoxic conditions. Red blood cell counts were higher in high temperature, but oxygen levels showed no effects on this parameter, which leads us to believe hypoxia triggers an increase in white cell numbers. These changes seem to have negatively impacted the condition of the fish, as individuals on the high temperature conditions exhibited much lower condition index values.