South Adriatic Sea is an interesting yet relatively unknown area when it comes to cetaceans and their use of the area. Fin whales, Cuvier’s beaked whales, Risso’s dolphins, bottlenose dolphins, striped dolphins and sperm whales have all been recorded in the area through aerial surveys carried out by BWI and their partners.  Additionally, deepest parts of South Adriatic have been identified as  important area for Cuvier’s beaked whales, species particularly sensitive to noise.

All cetaceans use sounds to communicate and some even use it for navigation and hunting prey. As sound is so important, they are also very sensitive to noise and different anthropogenic sounds like those coming from ships, underwater construction and drilling and seismic surveying.

A new research

High-frequency Acoustic Recording Package (HARP)

In order to obtain additional information and understanding of how dolphins and whales use South Adriatic and what are the various anthropogenic sounds present in the area the Blue World Institute and Croatian Natural History Museum  in cooperation with Department of Marine Biology, Texas A&M University Galveston developed a research project to study cetaceans and sea ambient noise in the Southern Adriatic through use of the High-frequency Acoustic Recording Package (HARP).

HARP is an autonomous acoustic recording device that enables recording of sounds in the marine environment developed by scientists from Scripps Institution of Oceanography. HARP can record wide acoustic spectrum continuously enabling long term acoustic monitoring. HARP can record sounds from baleen whales that vocalise using low frequencies and dolphin clicks of higher frequencies. Through its continuous operation HARP also records sea ambient noise and sounds like impulsive noise coming from seismic operation or sonar.

HARP deployment

After long hours of preparation of the equipment in Croatian Natural History Museum in Zagreb, the team of scientists – prof. Ana Širović (TAMUG), dr. Draško Holcer (CNHM) and dr. Nikolina Rako Gospić (BWI) headed to Dubrovnik. Thanks to the cooperation with Institute for Marine and Coastal Research, University of Dubrovnik and particularly support from “Influence of thermohaline circulation variations in the Eastern Mediterranean on the plankton community of the South Adriatic: ecological and genetical approach (AdMedPlan)” project of dr. Mirna Batistić and dr. Rade Garić, the team boarded the oceanographic vessel “Naše more” and headed to the open waters of the southern Adriatic to deploy the HARP. When reaching depths of over 1000 m the team successfully deployed HARP that will now record every sound made in the southern Adriatic for the next 6-7 months. This is the first time such equipment has been deployed in the Adriatic (and even eastern Mediterranean). It will help us understand cetacean presence and acoustic environment cetaceans of the Adriatic live in!

We are looking forward to the results and further deployment.