Evaluating feasibility of functional near-infrared spectroscopy in dolphins.

Significance: Using functional near-infrared spectroscopy (fNIRS) in bottlenose dolphins () could help to understand how echolocating animals perceive their environment and how they focus on specific auditory objects, such as fish, in noisy marine settings.

Aim: To test the feasibility of near-infrared spectroscopy (NIRS) in medium-sized marine mammals, such as dolphins, we modeled the light propagation with computational tools to determine the wavelengths, optode locations, and separation distances that maximize sensitivity to brain tissue.

Approach: Using frequency-domain NIRS, we measured the absorption and reduced scattering coefficient of dolphin sculp.

Conditioned Variation in Heart Rate During Static Breath-Holds in the Bottlenose Dolphin ().

Previous reports suggested the existence of direct somatic motor control over heart rate ( ) responses during diving in some marine mammals, as the result of a cognitive and/or learning process rather than being a reflexive response. This would be beneficial for O storage management, but would also allow ventilation-perfusion matching for selective gas exchange, where O and CO can be exchanged with minimal exchange of N. Such a mechanism explains how air breathing marine vertebrates avoid diving related gas bubble formation during repeated dives, and how stress could interrupt this mechanism and cause excessive N exchange.

Water temperature fluctuations as a key driver of cetacean pox (tattoo) lesions in bottlenose dolphins Tursiops truncatus.

Dolphin tattoo lesions are superficial non-raised skin lesions caused by poxviruses. Their presentation can vary but typical lesions in bottlenose dolphins are circular to ovoid with concentric rings of black stippling. These lesions have at times been suggested as an indicator of overall dolphin health and welfare.

Ventilation and gas exchange before and after voluntary static surface breath-holds in clinically healthy bottlenose dolphins, .

We measured respiratory flow (), breathing frequency (), tidal volume (), breath duration and end-expired O content in bottlenose dolphins () before and after static surface breath-holds ranging from 34 to 292 s. There was considerable variation in the end-expired O, and following a breath-hold. The analysis suggests that the dolphins attempt to minimize recovery following a dive by altering and to rapidly replenish the O stores.