The Effects of Marine Traffic on the Respiratory Behavior of Bottlenose Dolphins off the Northeastern Coast of Sardinia, Italy

Abstract

The common bottlenose dolphin can be found in oceans worldwide and has been the subject of a variety of studies over the years. Its popularity has resulted in increased attention from the growing marine tourism industry. This study seeks to examine the effects of increased boat traffic on a population of wild bottlenose dolphins off the northeastern coast of Sardinia, Italy. Previous research on various dolphin populations worldwide has shown that increased marine traffic can influence the diving and respiratory behavior of bottlenose dolphins, causing them to extend the length of their dives in a technique called vertical avoidance. This strategy induces significant energy costs, causing a decrease in their overall fitness. As the study base of this research area, Golfo Aranci also functions as a popular tourist destination, receiving a sizable increase in the number of tourist and recreational boats during the summer months of June, July, and August. Over the course of 60 days, data on the respiratory and diving behavior of the local resident bottlenose dolphin population was collected and subsequently analyzed using the statistical package, R. The main objectives of this study are to describe and quantify the diving behavior of this dolphin population, as well as to examine if boat presence influences their behavior in any way. The results of this research support previous studies in the area, which indicate that the presence of marine traffic does not influence dolphin diving behavior. This study also provides the first quantification of gender specific dive behavior, as well as gender specific responses to marine traffic. Results show that females and males in this population do not exhibit different behavioral strategies in response to boat presence. This research contributes to a long-term study of this particular population, in order to ensure their protection.