The maritime area stretches from Senegal to Angola.
It's now the most dangerous in the world - seeing nearly half of all the attacks this year.
Al Jazeera's Ahmed Idris reports from Lagos in Nigeria, one of the worst-affected countries.
- Subscribe to our channel:
- Follow us on Twitter: https://twitter.com/AJEnglish
- Find us on Facebook: https://www.facebook.com/aljazeera
- Check our website: https://www.aljazeera.com/