Evaluation des interactions entre les dauphins et les filets de peche des sardiniers de la région de Mahdia et réduction de leur impact par l'utilisation des ondes acoustiques générées par le "tube dauphin"

Abstract

The dolphin attacks to gillnet and the small pelagic fish purse seine are very frequent along the Tunisian coast. Such interaction has an impact on fishing vessels. To reduce these interactions the National Institute of Marine Sciences and Technologies (INSTM) conceived a mechanical acoustic waves generator, called the "Dolphin Tube", which is able to chase the dolphins to leave the fishing areas. Following a certain period the device showed no effect on dolphin. The main purpose of this study is to evaluate the interactions between dolphin and fishing nets in order to introduce some amelioration to the "Dolphin Tube". The experimentation of the modified tube device showed an improvement to disturb the dolphin echolocation system and causes a masking of the fishing nets. Also, the intensity of these waves are not supported by the auditive system of the dolphin. The use of this new form of Tube showed an immediate action on every located dolphin's school which disappeared from the fishing area.