On behalf of my co-authors I am pleased to announce our new open-access publication:
Pace D.S., Di Marco C., Giacomini G., Ferri S., Silvestri M., Papale E., Casoli E., Ventura D., Mingione M., Alaimo Di Loro P., Jona Lasinio G. and Ardizzone G.D. (2021). Capitoline dolphins: residency patterns and abundance estimate of Tursiops truncatus at the Tiber River estuary (Mediterranean Sea). Biology 10(4), 275.
Abstract
Periodic assessments of population status and trends to detect natural influences and human effects on coastal dolphins are often limited by lack of baseline information. Here, we investigated for the first time the site-fidelity patterns and estimated the population size of bottlenose dolphins (Tursiops truncatus) at the Tiber river estuary (Tyrrhenian Sea, central Mediterranean) between 2017-2020. We used photoidentification data and site-fidelity metrics to study the tendency of dolphins to remain in, or return to, the study area, and capture-recapture models to estimate the population abundance. A number of 347 unique individuals were identified. The hierarchical cluster analysis highlighted 3 clusters, labelled as "Resident" (individuals encountered at least 5 times in 3 different months, over 3 distinct years; n=42), "Part-time" (individuals encountered at least on 2 occasions in a month, in 2 different years; n=73) and "Transient" (individuals encountered in 1 or more occasions in more than 1 month, none of them in more than 1 year; n=232), each characterized by site-fidelity metrics. Open POPAN modeling estimated a population size of 529 individuals (95% CI: 456–614), showing that the Capitoline (Roman) coastal area and nearby regions surrounding the Tiber river estuary represent and important, suitable habitat for bottlenose dolphins, despite its proximity to one of the major urban centers in the world (the city of Rome). Given the high number of individuals in the area and the presence of "Residents" with strong site-fidelity, we suggest that conservation plans should not be focused only close to the Tiber river mouths but extended on a broader scale.
Keywords: abundance; site-fidelity; Tiber river; bottlenose dolphin; Tursiops truncatus; capture- recapture; Mediterranean Sea
With very best wishes,
Abstract
Periodic assessments of population status and trends to detect natural influences and human effects on coastal dolphins are often limited by lack of baseline information. Here, we investigated for the first time the site-fidelity patterns and estimated the population size of bottlenose dolphins (Tursiops truncatus) at the Tiber river estuary (Tyrrhenian Sea, central Mediterranean) between 2017-2020. We used photoidentification data and site-fidelity metrics to study the tendency of dolphins to remain in, or return to, the study area, and capture-recapture models to estimate the population abundance. A number of 347 unique individuals were identified. The hierarchical cluster analysis highlighted 3 clusters, labelled as "Resident" (individuals encountered at least 5 times in 3 different months, over 3 distinct years; n=42), "Part-time" (individuals encountered at least on 2 occasions in a month, in 2 different years; n=73) and "Transient" (individuals encountered in 1 or more occasions in more than 1 month, none of them in more than 1 year; n=232), each characterized by site-fidelity metrics. Open POPAN modeling estimated a population size of 529 individuals (95% CI: 456–614), showing that the Capitoline (Roman) coastal area and nearby regions surrounding the Tiber river estuary represent and important, suitable habitat for bottlenose dolphins, despite its proximity to one of the major urban centers in the world (the city of Rome). Given the high number of individuals in the area and the presence of "Residents" with strong site-fidelity, we suggest that conservation plans should not be focused only close to the Tiber river mouths but extended on a broader scale.
Keywords: abundance; site-fidelity; Tiber river; bottlenose dolphin; Tursiops truncatus; capture- recapture; Mediterranean Sea
With very best wishes,
Daniela
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Daniela Silvia Pace, PhD
Department of Environmental Biology
Marine Ecology Lab
Sapienza University of Rome
Viale dell’Università 32
00185 Rome, Italy
mail: danielasilvia.pace@uniroma1.it
mobile: +39 346 1039652
office: +39 06 4991 4763
skype: lagenorinco
Department of Environmental Biology
Marine Ecology Lab
Sapienza University of Rome
Viale dell’Università 32
00185 Rome, Italy
mail: danielasilvia.pace@uniroma1.it
mobile: +39 346 1039652
office: +39 06 4991 4763
skype: lagenorinco