Cardiorespiratory patterns of male South American sea lions (Otaria flavescens) resting on land.

The goal of this study was to characterize the cardiorespiratory patterns of male South American sea lions (SASLs, Otaria flavescens) resting on land. We recorded respiratory and heart rate (n = 360 individuals studied) by observing the nostrils, chest movements and the impact of the heart on the thoracic wall. The sea lions breathe apneustically with a pause on inspiration, representing 74% of the respiratory cycle. The mean breathing frequency was 3.2 ± 1.0 breaths min-1, with a breathing cycle presenting periods of bradypneas, tachypneas, and long-term post-inspiratory pauses. The normal heart rate (nHR) was 73.4 ± 14.5 beats min-1 and no significant differences were observed between age classes. All animals showed variability in HR in relation to respiratory phases (Inspiration: 101.2 ± 18.4 beats min-1; post-inspiratory pause: 73.4 ± 14.5 beats min-1; expiration: 64.6 ± 17.7 beats min-1), consistent with respiratory sinus arrhythmia (RSA). The mean HR (measured during all respiratory phases) was 79.9 ± 22.7 beats min-1, and was significantly different between age classes. The total duration of respiratory cycle, and duration of both inspiration and expiration, decreased with an increment in ambient temperature, with no variation in the pause duration. Heart rate during pause and expiration was significantly higher during high temperatures. Similar changes in cardiorespiratory patterns have been reported in other pinnipeds. Our results showed ontogenetic differences in development and typical variations with environmental and behavioral variables.

Doppler echocardiography in a healthy, non-sedated Southern Sea Lion (Otaria flavescens) - a preliminary approach about the feasibility and clinical utility.

Echocardiography is commonly used in veterinary clinical practice for many species but is not as easily applied in non-sedated marine mammals. Additionally, Doppler echocardiography provides further information on hemodynamics, estimation of cardiac output, characterization of flow patterns, and diastolic function. However, its applications in marine mammals have not been as widely explored either. The present report aimed to characterize the left ventricle structure and function of the Southern Sea Lion (Otaria flavescens) through a Doppler echocardiography study. Data were obtained from a healthy animal trained for different veterinary examination routines. This communication constitutes the first report of Doppler echocardiography with stroke volume, and cardiac output measurement in pinnipeds, and the first report of measurement of myocardial performance index in aquatic mammals. This data brought initial information about in vivo structure and function of the heart of the Southern Sea Lion that can be safely and effectively evaluated with the use of transthoracic Doppler echocardiography. Our data have both clinical and research implications for future studies evaluating diseases of the cardiopulmonary system in pinnipeds, and cardiovascular physiology investigation in diving mammals.

First description of the Burmeister porpoise (Phocoena spinipinnis) electrocardiogram.

The aim of this study was to make the first characterization of the electrocardiogram (ECG) of the Burmeister porpoise (Phocoena sipinipinnis). A total of three ECGs were made in one, wild juvenile female (body weight = 32.5 kg, Lt = 1.45 m), temporarily held in captivity for rehabilitation at Mar del Plata Aquarium (Argentina). For ECG recordings, the animal was removed from its pool on a stretcher under constant veterinary supervision. A traditional six-lead system in the frontal plane was used, with the typical four "extremities" electrodes positioned bilaterally. ECGs were readable and all waves were detectable. The QRS complexes were characterized by Q wave absence in all leads. The ECG characteristically displayed distinctly defined STs, with a T wave clearly differentiated from the QRS complex. An STs elevation was detected in leads II and III. The mean electrical axis was -79°, meaning a cranial left axis orientation. The animal showed normal sinus rhythm and heart rate (HR) showed a continuous oscillation between tachycardia and bradycardia. Mean HR from all recordings was 147.02 ± 24.95 bpm (range = 71-176, n = 178). Evidence of the occurrence of respiratory sinus arrhythmia was detected through HR variations and RR interval differences, which suggested an adequate cardiovascular system compensation to handling conditions. This study has reported ECG amplitude and duration measurements of a potentially healthy specimen, which represents the starting point for the determination of normal ECG values for this species. Also, it has confirmed that ECG is a valuable noninvasive tool for rapid cardiac health assessment in small cetaceans.

Plastic ingestion in Franciscana dolphins, Pontoporia blainvillei (Gervais and d'Orbigny, 1844), from Argentina.

Plastic debris (PD) ingestion was examined in 106 Franciscana dolphins (Pontoporia blainvillei) incidentally captured in artisanal fisheries of the northern coast of Argentina. Twenty-eight percent of the dolphins presented PD in their stomach, but no ulcerations or obstructions were recorded in the digestive tracts. PD ingestion was more frequent in estuarine (34.6%) than in marine (19.2%) environments, but the type of debris was similar. Packaging debris (cellophane, bags, and bands) was found in 64.3% of the dolphins, with a lesser proportion (35.7%) ingesting fishery gear fragments (monofilament lines, ropes, and nets) or of unknown sources (25.0%). PD ingestion correlated with ontogenetic changes in feeding regimes, reaching maximum values in recently weaned dolphins. Because a simultaneous increase in gillnet entanglement and the bioaccumulation of heavy metals take place at this stage, the first months after trophic independence should be considered as a key phase for the conservation of Franciscana dolphin stocks in northern Argentina.