Sea workers are distinguished from other productive groups due to a series of characteristics based on the very nature of working at sea and the Workplace itself (the ship): mobility, isolation and hazard level.

From a psychological point of view, a ship represents an entire institution in that it constitutes a closed environment in which the worker has to carry out all personal, social, and work-related activities. Its mobility means that sea workers are exposed to constant changes and particular difficulties, especially when the ship is moored in foreign ports.

Similarly, the nature of the work performed by sea workers and fishermen not only affects the workers themselves but also their family environment, either directly or indirectly.

The Social Marine Institute (ISM), in its capacity as the institution responsible for social issues within the maritime-fishing sector, and in response to the need for specific, fully comprehensive social care in this sector, provides a global system of social protection to complement Social Security protection mechanisms. This system is governed and reviewed within the framework of the Action Plans of the Ministry of Labour and Social Security.