Heart rates were monitored in the pebble crab, Gaetice depressus using a non-invasive, computer aided cardiac monitoring system. A high degree of intra- and interindividual variability was observed, as was the presence of endogenous circatidal and circadian rhythms. Both acute and sublethal toxicities of mercury were determined. LC50´s (96) for mercury were between 0.16-0.20 mg l-1. Exposure to HgCl2 above LC50 (96) (0.3 mg Hg l-1) resulted in rapid and statictically significant increases in heart rate whereas exposure to a concentration lower than LC50 (96) (0.1 mg Hg l-1) resulted in progressive reduction in heart rate similar to that of control crabs.
Aagaard, A., Styrishave, B., Warman, C. G., & Depledge, M. H. (2000). The use of cardiac monitoring in the assessment of mercury toxicity in the subtropical pebble crab Gaetice depressus (Brachyura: Grapsidae: Varuninae). Scientia Marina, 64(4), 381–386. https://doi.org/10.3989/scimar.2000.64n4381