Ergonomic Risk Assessment of Sea Fisherman Part IV: Tunisian Chapter

Following our experiences in Italy in Mazara del Vallo and Chioggia Marinas, we had another one in Tunisia in Sfax Marina. Aim of this paper is a biomechanical risk assessment of fishermen working on a vessel smaller than those previously analyzed in Italy and in a different socio-cultural context. The task that involved most of the crew’s working time was the sorting. We assessed this task by ISO Standard 11226 and 3DSSPP software. The maximum recommended exertion duty cycle, listed as a percentage of job time from the 14 analyzed frames with 3DSSPP, was between 2.3 and 14%. This data confirms that workers’ postures during sorting task were critical. In these task workers flexed the trunk over 90° for approximately 10 min for every catch. Both maximum exposure time (1 min) and maximum acceptable trunk flexion (60°) threshold, defined by ISO 11226, were exceeded. Moreover, it should be considered that ISO 11226 does not consider boat instability that significantly impacts biomechanical risks. The maximum posture holding time before the occurence of fatigue, according to Potvin’s mathematical model, is lower than the time held by workers. Trunk maximal values were between 35s and 125s and the lower limb joints values rarely exceeded two minutes of maximum exposure. Estimated values of the percentage of Maximum Voluntary Contraction (%MVC) were between 35% and 61% for the trunk and between 31.4% and 39.2% for the neck. The lower limbs %MVC values were remarkable for the hips (between 28% and 68%), knees (between 31% and 88%) and ankles (between 27% and 94%). This new experience confirmed medium-high risk levels during the sorting process. Furthermore given the reduced size of the boat, the crew couldn’t improve their working conditions with low-cost solutions, as in Italy. For operational problems, manual handling of the fish crates wasn’t assessed although the placement of the freezer on the deck of the boat, instead of the bottom floor as in Mazara del Vallo, is certely less stressful.