Introduction

Physical activity is considered an integral component of health, and the ability to perform a set of behaviors helps us assess fitness and health.¹ To evaluate the physical fitness of our population of bottlenose dolphins, we created a fitness test suited for these aquatic animals, ensuring that it can be considered as an exercise routine.

Considering our mixed age-range and sex population, and access to open water, the authors compared all the categories mentioned. Furthermore, knowing that dolphins mask illness extraordinarily well, we hope to implement this test as an early examination to help decide whether an individual is experiencing health issues but not demonstrating obvious signs of illness.

Materials and Methods

This study included a total of 18 dolphins, from both sexes and ages ranging from 2 years old up to 32. We divided the age categories into calves (<3 years), subadults (3–7 years) and adults (over 7 years and sexually mature). We included six dolphins into the open-water category as they regularly participate in open-water sessions. We compared these to six age-comparable dolphins that do not participate in open-water sessions.

The standard fitness test protocol consists of measuring the heart rate (HR) and breath count (BC) for 60 seconds to obtain a 'base' after an initial 3-minute rest period. This is followed by a series of chained high-energy behaviors, after which the 60-second measurements are repeated, to obtain the actual 'test.' After another 3-minute rest period, a final 'recovery' is measured.

Results

On the analysis of the average of our population, there is a significant difference for both HR and BC between all measurements with p<0.05. There was no significant difference in averages between both sexes.

When comparing the different age categories, there was a significant difference in 'test' HR between adults and calves with p<0.05. For BC, there were significant differences in 'test' and 'recovery,' between both adults and calves, and subadults and calves, with p<0.05.

On the dolphins that are regularly participating in our open-water program, we found a significant difference in both ´base´ and ´recovery´ HR, as it is consistently lower than for dolphins that do not go outside, with p<0.05. On the BC, we found a significant difference in 'base' with p<0.05.

Discussion

The goal of this study was to create a new and objective measurement of fitness that could be correlated with health in a population of captive bottlenose dolphins. We can conclude that the routine of high-energy behaviors can be seen as exercise, since it resulted in a significant increase in both HR and BC. Based on the significant difference between 'base' and 'recovery,' the authors believe that the dolphins included in this study might need more than three minutes to recover completely.

The age category calves had a higher HR on 'test' than adults, possibly indicating an increased demand in blood flow and oxygenation during exercise. Adding to this was the finding of higher BC in both 'test' and 'recovery' for calves compared to the other age categories, likely indicating a less developed respiratory system.

The authors believe that by having regular open-water sessions, the general fitness of the animals can be increased, and that might contribute to a better overall health status. As the fitness test is part of our Health Assessment Plan, it is implemented monthly to each dolphin in our population, and whenever a trainer is concerned about the overall look of the dolphin. As a first-line test of health (and even behavior) the expectation is that a sick or misbehaving dolphin will either refuse or not perform to that individual's standard, either indicating a health or behavioral abnormality.

Acknowledgements

The authors are grateful for the assistance from the Dolphin Academy Curaçao and Curaçao Dolphin Therapy Center management and trainers (George Kieffer, Anne van den Heuvel, Zenzi Willems).

* Presenting author

Literature Cited

1.  Bates H. 2006. Daily Physical Activity for Children and Youth: A Review and Synthesis of the Literature. Alberta Education, Alberta, Canada 72p.