Spatial analyses of marine traffic and resident cetaceans in Madeira.
Supervisor: Luis Freitas (Madeira Whale Museum)
During the last decades, maritime traffic has greatly impacted the marine environment and has been consideredmany times as a high potential disturbance against cetaceans. Madeira archipelago waters are considered an oasisin the middle of the Atlantic ocean for the high cetaceans diversity that rely on it for feeding, resting and nursingpurposes. However preliminary studies looking at Automatic Identification System (AIS) transmission hasrevealed some level of maritime traffic activity in these waters, from shipping and ferry navigation routes.Therefore, the present study aims to characterise the maritime traffic in Madeira’s inshore waters between 2008and 2018 looking at different classes of maritime traffic, to later integrate it into a generalized additive model(GAM) analysis with the purpose of investigating potential relationships between the distribution of groups oftwo cetacean species with resident groups in the archipelago (bottlenose dolphin and short-finned pilot whale)and maritime traffic covariates in these waters. The results show an overlap between areas preferred by these twospecies and areas where maritime traffic is more intense, but no clear relationships between maritime trafficcovariates and cetaceans groups distribution was found. The results also show that further fishing activities, offthe coast of Madeira represent a very important part of the maritime traffic in the study area when compared totankers, cargo and passenger ships that are spatially more related with resident cetaceans habitat. GAMs modelresults suggest that bottlenose dolphins are more likely to be exposed to maritime traffic than short-finned pilotwhales. Our study demonstrates that maritime traffic, if rightly selected and in addition to environmentalcovariate, could explain part of the spatial distribution groups’ of resident cetaceans. Nevertheless, the overlapbetween areas of higher local maritime traffic and these main areas of distribution in the archipelago’s inshorewaters may result in potential negative impacts on these populations. Future studies, including acoustic andphysiological studies, could investigate the consequences of such interactions between specific types of boatsand resident cetaceans populations in Madeira.