Dolphin Population Conservation

The common bottlenose dolphin is one of the Cetacean that most comes into contact with human activities, entering often into competition for food resources or being exposed to sea-related tourism. It is a species with plastic behaviour, able to adopt different behavioural strategies according to geographical and ecological context. Despite being among the most studied species of Cetacean, still many aspects of its ecology remain unknown. Above all, it is the effect of human activities on sub-populations of small size, therefore more vulnerable, that is often totally unknown.

Main question 1: How many dolphins live in our study area?

The cornerstone of many ecological studies is knowing the abundance of the population in the study area. One of the most used ways to estimate a dolphins' population size is to capture and mark dolphins (by means of the photo-identification technique) and to see what fraction of individuals carry marks in successive samplings.

Reason: Monitoring the population sizes give us the basic information to understand the temporal dynamic of the population, to detect trends and incipient change and to evaluate eventual management needs.

Main question 2: Can we predict habitat preferences of bottlenose dolphins? 

Species distribution modelling (SDM) has a long tradition in ecology and it is becoming increasingly important in applied ecology as researchers and managers seek to understand current species distribution patterns and to predict future distributions in the face of climate change, human-assisted invasions and many other ongoing environmental changes. One of the most widely used SDMs in case of incomplete information on sampling effort and not-independent data is maximum entropy (MaxEnt) modelling.  

Reason: Knowing the distribution and ranging patterns of Cetaceans is important for implementing effective boundaries for SCIs (Sites of Community Importance), SACs (Special Areas of Conservation) and marine protected areas and determining correct management. Moreover, the quantitative evaluation of trends in distribution and abundance is a fundamental requirement for species listed in Appendices II and IV of the Habitats Directive, such as the bottlenose dolphin, and also a requirement for the Member States of the Maritime Strategies Framework Directive.



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Pulcini M., Pace D., La Manna G., et al. 2013. Distribution and abundance estimates of bottlenose dolphins (Tursiops truncatus) around Lampedusa Island (Sicily Channel, Italy): Implications for their management. Journal of the Marine Biological Association of the UK 94(6):1-10.

La Manna G., Clò, S., Papale, E. and Sarà, G. 2010. Boat traffic in Lampedusa waters and its relation to the coastal distribution of common bottlenose dolphin (Tursiops truncatus). Ciencias Marinas 36(1).   

La Manna G., Ronchetti F. and Sarà G. 2016. Predicting common bottlenose dolphin habitat preference to dynamically adapt management measures from a Marine Spatial Planning perspective. Journal of Ocean and Coastal Management.

La Manna G. and Ronchetti F. 2018. Relazione sul monitoraggio della presenza e distribuzione del tursiope nell'area del Nord Sardegna compresa.....Determinazione n. 2777 del 12/10/2018 del Comune di Alghero.