A new study undertaken at the University of Haifa and conducted in cooperation with the University of Zagreb found that the underwater noise emissions from small vessels may reach levels comparable to those of large commercial vessels.
As part of the research, researchers created the largest database of its kind of small vessels, cataloguing video and acoustic recordings of over 1,200 vessels in the Adriatic Sea. The database categorizes vessels according to the type, size, and speed. The data collection system employed by the researchers included a combination of an optical camera and an acoustic recorder to capture video recordings of small vessels passing through the channel.
Our findings show that under certain conditions, small vessels can emit significant underwater noise pollution that influences the behavior of marine animals, including marine mammals, fish, and invertebrates,
… explained Prof. Roee Diamant from University of Haifa’s Charney School of Marine Sciences, who authored the study.
Using a dedicated machine learning system developed as part of the study, the researchers were able to identify the vessels and estimate their type, size, and speed.
In order to accurately record the noises of the transiting vessels in the area, the researchers positioned the acoustic recorder in the center of the channel, at a depth of about 30 meters, enabling them to match each vessel identified in the video footage to the acoustic signal it created while passing through the channel. The acoustic processing included an analysis of the sound pressure levels and frequency spectrum of various vessels.
While marine mammals such as dolphins and whales, who rely on sound waves for communication, navigation, and the location of prey, are particularly impacted, it has also been proven that underwater noise pollution affects other marine animals, including fish and turtles.
The International Maritime Organization issued regulations to reduce underwater noise from large ships and some countries have placed limits on the permittable speed of commercial vessels in coastal areas that are home to marine animals. However, there are no current regulations that address smaller vessels,
… noted Mr. Mark Shipton, a doctoral student in the Department of Marine Technologies at University of Haifa who was responsible for undertaking the acoustic analyses in the study, adding that In fact, the impact of noise from small vessels may be greater than those of large commercial vessels as smaller vessels cruise in coastal waters, where most marine life is concentrated.
To remind, in 2023, the IMO MEPC 80 approved the Revised guidelines for the reduction of underwater radiated noise from shipping to address adverse impacts on marine life. These guidelines, which took effect from 1 October 2023, aim to reduce underwater radiated noise from ships and concern particular ship and equipment designers, shipbuilders and shipowners and operators, classification societies, suppliers, manufacturers and other stakeholders.
