Study Shows Human Interaction Alters Dolphin Behavior

Written by on November 16, 2009 in Marine Life
Bottlenose dolphin - eco-tourism in Mozambique - Credit: Angie Gullan/Marine Photobank

Bottlenose dolphin – eco-tourism in Mozambique – Credit: Angie Gullan/Marine Photobank

Researchers are studying the impacts human behaviors, as innocent as they may be, can have on bottlenose dolphins and have already determined they change their behavior.

In a paper published in the Journal of Marine Animals and Their Ecology, Antonella Arcangeli from the Accademia del Leviatano, Rome and ISPRA, Dipartimento Difesa della Natura, Rome, Italy and Roberto Crosti from the School of Environmental Science, Murdoch University, Perth, Western Australia present their findings of interactions between bottlenose dolphins and a dolphin-watching tour boat in Bunbury, Western Australia.

Bottlenose Dolphin

Bottlenose Dolphin

There is so far little known about the impacts dolphin watching tours have on these marine mammals, but already growing concern about the effects of the ecotourism industry on their behavior and conservation.

The researchers compared the dolphin behavior patterns in the presence of the tour boat and without. The analysis of their observation show that “the presence of the Tour Boat can influence the duration and frequency of behavioral states and also the structure of the population. The time spent resting and feeding decreased, whereas travelling increased. The frequency of all the behavioral states increased, in particular travelling, resting and feeding . The group structure was also influenced, as dolphins tend to spread in more groups of fewer animals in the presence of the Tour Boat.”

Bottlenose dolphins in Arranmore at the Donegal Coast - Credit © John Rafferty Photography/Marine Photobank

Bottlenose dolphins in Arranmore at the Donegal Coast – Credit © John Rafferty Photography/Marine Photobank

The Common Bottlenose Dolphin is the best known species and inhabits warm and temperate waters of the world. It is in fact only absent from polar waters. The grey, 2-4 meter (6.6-13 feet) long dolphin lives in pods of typically 15 animals near shores — offshore groups of several hundreds have been seen — and uses sound for echolocation and communication.

The Dolphin Institute states that Bottlenose dolphins and other marine mammals face a number of conservation threats due to anthropogenic, or human-induced, impacts on the marine environment. Among the common threats to dolphins are habitat degradation, boat traffic, fishing interactions, pollution and direct takes. Find them all further explained here. It is protected in the U.S. by the Marine Mammal Protection Act. They are still generally plentiful in numbers, but are already almost depleted in some areas.

Indian Ocean Bottlenose Dolphin  -  Credit: Angie Gullan/Marine Photobank

Indian Ocean Bottlenose Dolphin – Credit: Angie Gullan/Marine Photobank

The study concludes that the short-term changes in behaviour pattern can be used as an early indicator of potential halt to animal vulnerability in order to assess and recommend appropriate management and conservation strategies especially in regions, such as the Mediterranean Sea, where, for the combination of many disturbance factors, cetacean populations are vulnerable.

Read the complete study and conclusions at “The short-term impact of dolphin-watching on the behaviour of bottlenose dolphins (Tursiops Truncatus) in western Australia” at http://www.oers.ca/journal/Volume%202/200921arcangeli.pdf

Materials compiled from the original study, The Dolphin Institute, American Cetacean Society

An adult female bottlenose dolphin with her young, Moray Firth, Scotland  -  Photographer: Peter Asprey  -  http://www.peter-asprey.com/

An adult female bottlenose dolphin with her young, Moray Firth, Scotland – Photographer: Peter Asprey – http://www.peter-asprey.com/

Copyright ©  2009 by Marine Science Today, a publication of OceanLines LLC

About the Author

About the Author: Celia is Director of Business Operations for OceanLines LLC and is a frequent contributor to both OceanLines and Marine Science Today. She is a certified diver and her favorite topic is marine biology, especially stories about whales. .

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  1. pratyush das says:

    It is a very very exciting paper about human interactions with human behaviour. As a marine biology student it is very essential for me to keep all these information with me for the growth of my knowledge.

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