Twenty-four Mediterranean fin whales were tracked in open sea with a method based on the assessment of the animal differential position in respect of the observer's absolute position aboard a vessel, with the concomitant recording of the respiratory activity. Short distance video recording was also performed in two whales, permitting the simultaneous determination of single breath expiratory ( T(E)) and inspiratory ( T(I)) durations. In the 24 whales swimming at an average velocity of 1.39 (0.47) m.s(-1) [mean (SD), range: 0.62-2.44 m.s(-1)], 2068 breaths organized in 477 respiratory cycles were observed. Each cycle entailed a prolonged apnoea dive phase [225 (91) s, T(dive)) followed by a period near the surface [62 (28) s, surfacing], during which a series of breaths [4.6 (1.8)] was performed at short intervals. On the basis of track length and swimming velocity, two groups of animals were devised differing for convolution of the course ( p<0.001), extension of ranging territory ( p<0.01) and horizontal swimming velocity ( p<0.05), which may represent two distinct behaviours. A possibly general mechanism of control of breathing in cetaceans was found, consistent with a model of constant tidal volume and variable respiratory frequency. Coherently with this model, T(E) was independent of T(I) or T(dive), in line with a passive expiration, while T(I) appeared to be negatively correlated with T(dive) ( p<0.05), otherwise suggesting, similarly with terrestrial mammals, a significant role of hypercapnic stimulation. The estimated O(2) consumption of about 150 l.min(-1) is in line with the general allometric regression for mammals and corresponds to an energetic expenditure of 85-95 kJ.kg(-1).day(-1).
Locomotor behaviours and respiratory pattern of the Mediterranean fin whale (Balaenoptera physalus)
Lafortuna CL;
2003
Abstract
Twenty-four Mediterranean fin whales were tracked in open sea with a method based on the assessment of the animal differential position in respect of the observer's absolute position aboard a vessel, with the concomitant recording of the respiratory activity. Short distance video recording was also performed in two whales, permitting the simultaneous determination of single breath expiratory ( T(E)) and inspiratory ( T(I)) durations. In the 24 whales swimming at an average velocity of 1.39 (0.47) m.s(-1) [mean (SD), range: 0.62-2.44 m.s(-1)], 2068 breaths organized in 477 respiratory cycles were observed. Each cycle entailed a prolonged apnoea dive phase [225 (91) s, T(dive)) followed by a period near the surface [62 (28) s, surfacing], during which a series of breaths [4.6 (1.8)] was performed at short intervals. On the basis of track length and swimming velocity, two groups of animals were devised differing for convolution of the course ( p<0.001), extension of ranging territory ( p<0.01) and horizontal swimming velocity ( p<0.05), which may represent two distinct behaviours. A possibly general mechanism of control of breathing in cetaceans was found, consistent with a model of constant tidal volume and variable respiratory frequency. Coherently with this model, T(E) was independent of T(I) or T(dive), in line with a passive expiration, while T(I) appeared to be negatively correlated with T(dive) ( p<0.05), otherwise suggesting, similarly with terrestrial mammals, a significant role of hypercapnic stimulation. The estimated O(2) consumption of about 150 l.min(-1) is in line with the general allometric regression for mammals and corresponds to an energetic expenditure of 85-95 kJ.kg(-1).day(-1).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
