Marine Mammal Observation | River Lagan

Marine Mammal Observation for extension to Lagan Pontoon

Project: Marine Mammal Observation during Piling Works in the River Lagan, for an extension to the Lagan Pontoon

Services ProvidedAVRIO was appointed by a client to carry out marine mammal observation services during construction works regarding extension to the Lagan pontoon, in the River Lagan Belfast. The works involved a land-based crane installing 600mm diameter piles, driven to a depth of 11m using a vibrating piling hammer. The works were located 4km from a significant Harbour Seal (Phoca vitulina) colony at Musgrave Channel. As such, a marine mammal observer was required during the construction phase of the development, to satisfy the project mitigation requirements. The services provided by AVRIO included the following:

o   Pre-observation desk study, to identify general location of Harbour seal colony at Musgrave Channel, and consultation with relevant databases e.g., National Biodiversity Network (NBN) Atlas or National Biodiversity Data Centre (NBDC) to note any other marine mammals observed within the area;

o   Utilisation of GIS to produce a site map, highlighting a 500m mitigation zone around the development site, for the Harbour seal colony, and other marine mammals;

o   Land-based marine mammal surveys over the 2-no. days of construction on-site, including pre-construction surveys 30-no. minutes before machinery commended, and continuous surveying until the construction works ceased, either for a temporary break or for the end-of-day;

o   Production of summary report of the observation, indicating the survey times, survey conditions and limitations, the equipment used, and any observation of marine mammals and their associated behaviours during observation;
Marine mammal observation took place over two days in September 2023. Pre-construction surveys were carried out thirty minutes prior to machinery works commencing to ensure no marine mammals were within a 500 metre radius (the mitigation zone) of the development. Surveying was continuous throughout the survey works. The observer utilised different vantage points to ensure the entirety of the mitigation zone was surveyed.
Over the course of the survey, there were no marine mammal observations. The observer was satisfied that there were no negative impacts on the harbour seal population, or any marine mammals during the construction phase of the development.

Photos of vantage points utilised by Observer during the marine mammal observation

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