Hemolymph clotting time as an indicator of stress in western rock lobster (Panulirus cygnus George)

A simple method to measure clotting time was introduced in an experiment st udying the effects of exercise stress on western rock lobster (Panulirus cy gnus). The treatment group lobsters (N = 8) were made to exercise (tail fli pping) in a 200 l tank for 2 min. Lobsters were then sampled immediately af ter exercise and once again 1 h later, Controls were sampled both before th e experiment started and after all the other samples were taken (pre- and p ost-exercise controls). Total hemocyte counts (THCs), differential hemocyte counts (DHCs), hemolymph clotting time, hemolymph protein content and lobs ter vigor were analyzed. THCs, DHCs, hemolymph clotting and vigor index sho wed response to treatment, THCs were increased significantly 1 h after exer cise (6.36 +/- 0.58 X 10(6) cells/ml) compared to pre- and post-exercise co ntrols (4.42 +/- 0.38 and 4.41 +/- 0.38 X 10(6) cells/ml, respectively). He molymph clotting time in the same experimental lobsters (43.7 +/- 2.0 s) we re decreased compared to pre- and post-exercise control groups (56.0 +/- 4. 1 and 52.7 +/- 2 2 s, respectively). Hemolymph clotting times were correlat ing with DHCs and hemolymph protein levels. Hemolymph clotting time is easi ly measured and could be a useful indicator of stress. (C) 2001 Elsevier Sc ience B.V. All rights reserved.