The shipping noise near channels and ports is an important contribution to the ambient noise level, and the depth of these sites is often less than 100 m. However less attention has been paid to the measurement in shallow water environments (Brooker, Humphrey, 2016). This paper presents extensive measurements made on the URN (underwater radiated noise) of a small fishing boat in the South China Sea with 87 m depth. The URN data showed that the noise below 30 Hz was dominated by the background noise. The transmission loss (TL) was modelled with FEM (finite element method) and ray tracing according to the realistic environmental parameters in situ. The discrepancy between the modelled results and the results using simple law demonstrates both sea surface and bottom have significant effect on TL for the shallow water, especially at low frequencies. Inspired by the modelling methodology in AQUO (Achieve QUieter Oceans) project (Audoly et al., 2015), a predicted model applied to a typical fishing boat was built, which showed that the URN at frequencies below and above 100 Hz was dominated by non-cavitation propeller noise and mechanical noise, respectively. The agreement between predicted results and measured results also demonstrates that this modelling methodology is effective to some extent.

The environment in general and the marine environment in particular forms an ecosystem. Such ecosystem is characterized by high interconnectivity and interdepen-dence of species inhabiting it. Often enough, marine ecosystems far exceed the limits of the State’s sovereignty. Thus, their effective protection and preservation shall be carried out on a cooperative basis, engaging all States sharing common environment. The first international treaty to tackle the issue of marine environmental protection on a systemic basis is the United Nations Convention on the Law of the Sea (UNCLOS). It is also a treaty which directly established an obligation to cooperate in ensuring this protection. However, homogenous international regulation is not capable of addressing regional varying circumstances of marine environment. As the example of the South China Sea shows, lack of cooperation between coastal States can result in an irreversible damage to the environment. On the other hand, a remarkable model of effective realization of the obligation to cooperate has been established in the region of the Baltic Sea. What we can learn from these experiences is that fulfillment of the obligation to cooperate on a re-gional basis is a prerequisite for effective protection and preservation of the marine environment.