Differential leukocyte counts were taken of blood smears collected from laboratory stressed adult Australian swellsharks Cephaloscyllium laticeps. We calculated the granulocyte (combined count of heterophils and neutrophils) to lymphocyte (G/L) ratio to use as a new physiological indicator of stress for sharks Animals were captured and stressed using commercial fishing gear (monofilament gillnet and mid-water longline) in a laboratory setting, with blood samples collected prior to capture and at predetermined intervals during a subsequent 72 h recovery period There was a significant increase in the G/L ratio of 29114 = 54.13 at 72 h post-capture during recovery from the 6-h gillnet capture plus 15-mintue air exposure. Six hours of longline capture plus 15 min of air exposure also evoked a significant Increase in the G/L ratio of 490.32 +/- 294 25 (24 h post-capture) and 590 53 +/- 277.65 (72 h post-capture) There was no significant change in the G/L ratio for control sharks that did not undergo capture stress but that experienced an identical blood-sampling regime as captured animals Our study presents findings of stress-Induced changes in leukocyte distribution within the peripheral blood of a shark species brought on by lymphopenia (decrease in lymphocytes) and granulocytosis (increase in granulocytes), and confirms this as a useful measure of the relatively rapid onset of stress in these animals.
|Pages (from-to)||534 - 538|
|Number of pages||5|
|Journal||Fish and Shellfish Immunology|
|Publication status||Published - 2010|