General Fisheries Commission for the Mediterranean - GFCM

Winner of the MedFish4Ever Award on innovative practices
in fishing technology

Reinforced seine as a mitigation measure against depredation by bottlenose dolphins

National Institute for Fisheries Research, Ministry of Agriculture, Fisheries, Rural Development, Water and Forests, Morocco

What is the project? 

“Projet Négro” aimed to mitigate the economic and biological interactions between bottlenose dolphins and purse seiners in Moroccan waters. Dolphins have learned to target the sliding nets used to encircle shoals of small pelagic fish, robbing catches, damaging gear, and putting themselves in danger too. This initiative – carried out by the National Institute for Fisheries Research (INRH) – aimed to determine whether and to what extent a new reinforced net design could prevent losses and limit interactions between the fishery and this protected species. In order to collect data for the experiment, INRH worked with local fishers from the ports of M’diq and Al-Hoceima. Onboard observers were deployed to assess the effectiveness of three different prototype seines The results were evaluated for fishing efficiency and resistance to attacks and were then compared with data collected from vessels operating with traditional purse seines during the same period of July 2018 to December 2020.

Why does this matter?   

The new reinforced seine represents an important step in the sustainable development of the fishery. The results obtained show a significant positive impact, in terms of reducing both damage to seines and incidental dolphin catches. By minimizing tears and damage to the net, the enhanced design lowers operational costs and the time spent mending gear, increasing productivity and the financial stability of fisher communities. By avoiding non-target catches, the new seine helps to protect vulnerable species, preserve fish populations and maintain the natural balance of the marine ecosystem. Importantly, the solution is replicable in other regions facing the same issue.

How is the project impactful?  

All three reinforced seine prototypes (large, medium and small) sustained fewer tears than the traditional purse seine. The large reinforced seine suffered 6 tears per tide following dolphin depredation, compared to 33 per tide for the normal purse seine. The medium prototype was torn 18 times compared to 91 for the normal purse seine. Finally, the small reinforced seine saw 6 tears compared to 19 in the traditional model. Overall, the results show that the enhanced seine has three key advantages over fishing with traditional gear: it increases fishing efficiency, improves resistance to dolphin depredation, and has lower repair costs.

Location and possibility of replication in the GFCM area of application

The locations of the initial trials – the ports of M’diq and Al Hoceima – were chosen because of the particularly high level of interactions between dolphins and purse seiners experienced there. A further extension to other ports in Morocco such as Jedha and Nador was also considered. The results obtained from the studies have the the potential for replication and application in similar regions facing comparable challenges anywhere in the GFCM area of application and beyond.