capture myopathy (cM), is a syndrome that occurs as the result of the stress during and after capture, handling, restraint, and transport of wild animals. Although cM has been described for many species of cetaceans, characterization of the acute cardiac injury-an important component of this syndrome-are still scarce. In this study, we firstly estimated a normal range for cardiac troponin I (cTnI) on cetaceans. Here, through biochemical analysis (especially of ctni) and histopathological, histochemical, and immunohistochemical correlations with decreased troponin immunolabelling, we studied the cardiac injury in live-stranded cetaceans. nine cetaceans which stranded alive on the canary islands (January 2016-June 2019) were included in this study. Sampled individuals presented elevated values of plasma ctni, which were correlated to histopathological lesions comprised of vascular changes and acute degenerative lesions. immunohistochemically, injured cardiomyocytes showed a decreased intrafibrillar troponin immunoreaction. This is the first attempt to establish a normal baseline range for cTnI in cetaceans, and the first study comparing plasma biomarkers values with histopathological and immunohistochemical findings. This approach allowed us to demonstrate the degree of cardiac damage as a result of injury, consistent with ischemia-reperfusion lesions. the knowledge gained here could improve decision-making procedures during stressful situations, mainly in live-strandings, handling, and rehabilitation, thereby reducing the mortality of cetaceans. All life forms have evolved mechanisms to cope with stressful situations in their lives 1. For cetaceans, live-stranding is a situation in which they are alive on the beach or in shallow water, and in distress due to being unable to free themselves and resume normal activity 2-4. Similar to humans and other animals, once the central nervous system of a cetacean perceives an internal (physiologic or psychogenic) or environmental threat to their homeostasis, the threat being the stressor, a biological response is developed 5-7. Irrespective of the animal's previous health, stranding creates an anomalous and extreme situation for an organism that it is not anatomically or physiologically adapted to handle. It is a pathological entity in which acute stress is the central axis of its etiopathogenesis, presenting clinical and lesional findings that can cause the death of the animal or seriously aggravate a previous disease over the period of capture or captivity. This reaction may in turn influence the subsequent rehabilitation and recovery of affected animals, since live-stranded cetaceans are frequently debilitated when rescued. Therefore, although the stranding response is intended to improving the health and welfare of these animals, some "rescue and recovery" activities may in fact be counterproductive 4,8-13. Deaths of live-stranded cetaceans may be attributed to the so-called "stress response syndrome" or "alarm reaction, " which are thought to have analogous mechanisms t...