Pile testing has commenced at our worksite in Tanzania. Among the mitigation measures for safeguarding marine life during water-based activities, we introduced the bubble curtain, which we presented here (add link) two weeks ago. In addition to the bubble curtain, we have implemented a program of marine mammal observers (MMOs). We spoke with Benoit Lussis, Environmental Coordinator, who explained the vital role of these observers.
Q: Could you provide more information about the marine mammal observation programme on the Tanga jetty project?
A: Our marine mammal observation program is a component of a broader global protocol aimed at safeguarding whales and dolphins from the underwater noise generated by pile driving. This comprehensive protocol encompasses visual observation, the use of a bubble curtain, implementing a soft start procedure, and employing passive acoustic monitoring techniques. Currently, three Marine Mammal Observers (MMOs) are actively involved in this project.
Instead of working with foreign external consultants, we took the option to train local staff for 3 weeks. This training is essential to ensure that MMOs are able to work in accordance with international guidelines, correctly identify the marine mammals, communicate appropriately with the construction team, make appropriate reports, etc. We are now working with 3 young, very enthusiastic MMOs!
Their primary responsibility is ensuring our activities comply with regulations and guidelines designed to protect marine mammals from harm while minimizing our impact on marine ecosystems.
Q: What are their specific duties?
A: Before initiating any piling activities, our MMOs conduct visual and acoustic observations to ascertain the absence of marine mammals in the vicinity (a pre-defined ‘exclusion zone’). This assessment determines whether it is safe to proceed with the piling. During the piling, MMOs continuously monitor the area using tools like binoculars and a passive acoustic monitoring system. They provide updates on marine mammal activities to on-site crews and project managers, advising them on when to proceed or halt operations.
Q: MMOs conduct both visual and acoustic monitoring. While visual monitoring is self-explanatory, acoustic monitoring may be less familiar. Could you elaborate?
A: Essentially, acoustic monitoring involves listening to sounds with underwater microphone. Here the microphone is anchored to the sea bed, but in other projects it could be towed behind a vessel or attached to buoys. It captures underwater sounds, including marine mammal vocalizations. On the Tanga jetty project, we use an autonomous passive acoustic monitoring system (PAM): if the system detects a marine mammal in the vicinity, it automatically sends an alert to the MMOs. Thanks to this system, we don’t need to work with an experienced PAM operator from an external consultant. The MMOs have everything in their hands to make their own decision and interpretations.
Q: What actions do MMOs take if they spot or hear a marine mammal?
A: If a marine mammal enters a predefined 'exclusion zone' (an area where the potential for harm or disturbance is high), MMOs send the message to halt activities to the construction team. The activity can only resume when the animal leaves the exclusion zone.
Q: Apart from observations, what other responsibilities do MMOs have?
A: MMOs record data about marine mammal sightings, including species, numbers, behaviour, distance from the activity, and any observed reactions to it. This data is essential for immediate decision-making and long-term impact analysis. French company Creocean, specialised in marine environment, oversees the work of the MMOs and ensure the scientific credibility of our programme. Regulatory agencies and environmental organisations also use the MMO’s reports to assess the effects of activities on marine mammals and refine guidelines and best practices.
“In conclusion, we deeply appreciate the role of our MMOs in ensuring our activities have minimal negative impact on marine mammals. Their presence on-site is indispensable in balancing our operational and regulatory needs with the conservation of marine ecosystems.”