Mid-distance re-sighting of a common bottlenose dolphin in the northern Adriatic Sea: insight into regional movement patterns

Genov, Tilen; Angelini, Valeria; Hace, Ana; Palmisano, Giuseppe; Petelin, Boris; Malačič, Vlado; Pari, Sauro; Mazzariol, Sandro

doi:10.1017/s0025315415001241

Cited by 13 publications

(15 citation statements)

References 41 publications

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“…The range of this local population is unknown (Genov et al 2016), but evidence from photo-ID (Genov et al 2009) and genetics (Gaspari et al 2015) suggest it is a distinct unit.…”

Section: Discussionmentioning

confidence: 99%

Behavioural and temporal partitioning of dolphin social groups in the northern Adriatic Sea

Genov

Centrih²,

Kotnjek³

et al. 2018

Mar Biol

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Complex social structure is a prominent feature in several mammal species. Such structure may lead to behavioural diversity not only among populations, but also within a single population, where different subsets of a population may exhibit different types of behaviour. As a consequence, understanding social structure is not only interesting biologically, but may also help conservation and management efforts, because not all segments of a population necessarily respond to or interact with human activities in the same way, or at the same time. In this study, we examined the social structure of common bottlenose dolphins (Tursiops truncatus) in the Gulf of Trieste and adjacent waters (northern Adriatic Sea), based on a 9-year dataset, using social network metrics and association indices. We assessed whether different segments of the population show differences in behaviour and interactions with fisheries. Dolphin social network was structured into distinct social clusters of mixed sexes. We found no evidence of male alliances. The two largest social clusters overlapped spatially, but not temporally, as they used the same area at different times of day. Such diel temporal partitioning does not appear to have been documented in cetaceans previously. The two clusters also differed in ways they interact with fisheries, as one regularly interacted with trawlers, while the other did not. This study demonstrates how different segments of animal populations can interact differently with human activities and in turn respond differently to anthropogenic impacts.

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“…The range of this local population is unknown (Genov et al 2016), but evidence from photo-ID (Genov et al 2009) and genetics (Gaspari et al 2015) suggest it is a distinct unit.…”

Section: Discussionmentioning

confidence: 99%

Behavioural and temporal partitioning of dolphin social groups in the northern Adriatic Sea

Genov

Centrih²,

Kotnjek³

et al. 2018

Mar Biol

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“…This makes it particularly susceptible to a range of anthropogenic impacts, including the exposure to organochlorine contaminants. This species is regularly present in the Gulf of Trieste and adjacent waters, where it has been continuously studied since 2002 (Genov et al 2008, Genov et al 2016. As a coastal, mobile and longlived top predator with strong site fidelity, it is a particularly good candidate for investigating the effects of organochlorine contaminants, and for regional monitoring of organochlorine pollution.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…The dolphin population inhabiting these and surrounding waters ( Fig. 1) has been the focus of a long-term study and monitoring by Morigenos -Slovenian Marine Mammal Society since 2002, primarily through boatbased surveys and photo-identification, and is now relatively well studied (Genov et al 2008, Genov 2011, Genov et al 2016. The population is present within the area year-round (Genov et al 2008, Genov 2011) and appears to be demographically and genetically distinct (Genov et , Gaspari et al 2015.…”

Section: The Study Populationmentioning

confidence: 99%

“…Ross et al 2000, Ylitalo et al 2001, Wells et al 2005 are still relatively rare. In our study, all sampled animals were photo-identified and are part of a wellknown population of about 150 individuals monitored since 2002 (Genov et al 2008, Genov et al 2009, Genov et al 2016, which adds additional value to this dataset. It allowed us to combine long-term records of identifiable individuals with individually-specific organochlorine…”

Section: Accepted Manuscriptmentioning

confidence: 99%

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Linking organochlorine contaminants with demographic parameters in free-ranging common bottlenose dolphins from the northern Adriatic Sea

Genov

Jepson

Barber

et al. 2019

Science of The Total Environment

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Male bottlenose dolphins have significantly higher PCB concentrations than females  Nulliparous females have significantly higher concentrations than parous ones  There are no differences among social groups  Majority of animals exceed the toxicity thresholds  Pollutant concentrations can successfully be linked with demographic parameters ABSTRACT Marine top predators, including marine mammals, are known to bio-accumulate persistent pollutants such as polychlorinated biphenyls (PCBs), a serious conservation concern for these species. Although PCBs declined in European seas since the 1970s-1980s ban, considerable levels still persist in European and Mediterranean waters. In cetaceans, stranded animals are a valuable source of samples for pollutant studies, but may introduce both known and unknown biases. Biopsy samples from live, freeranging cetaceans offer a better alternative for evaluating toxicological burdens of populations, especially when linked to known histories of identified individuals. We evaluated PCB and other organochlorine contaminants in free-ranging common bottlenose dolphins (Tursiops truncatus) from the Gulf of Trieste (northern Adriatic Sea), one of the most human-impacted areas in the Mediterranean Sea. Biopsies were collected from 32 male and female dolphins during 2011-2017. All animals were photo-identified and are part of a well-known population of about 150 individuals monitored since 2002. We tested for the effects of sex, parity and social group membership on contaminant concentrations. Males had significantly higher organochlorine concentrations than females, suggesting offloading from reproducing females to their offspring via gestation and/or lactation. Furthermore, nulliparous females had substantially higher concentrations than parous ones, providing further support for maternal offloading of contaminants. Overall, 87.5% of dolphins had PCB concentrations above the toxicity threshold for physiological effects in experimental marine mammal

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“…Examples of recovery and recolonization of former habitat by pinniped species are widely acknowledged (Bonin et al, ; Cammen et al, ; Grandi et al, ; Hoelzel, Fleischer, Campagna, Le Boeuf, & Alvord, ; Kirkwood, Warneke, & Arnould, ; MacMillan et al, ; Pyle, Long, Shonewald, Jones, & Roletto, ; Reijnders, van Dijk, & Kuiper, ). In addition, temporary migration and the occurrence of transient or visitor animals may have important implications for conservation of the populations and groups of many endangered marine mammals ranging across borders of different countries (Bearzi, Bonizzoni, & Gonzalvo, ; Genov et al, ; Stern, ).…”

Section: Discussionmentioning

confidence: 99%

On sightings of (vagrant?) monk seals, Monachus monachus, in the Mediterranean Basin and their importance for the conservation of the species

Bundone

Panou

Molinaroli

2019

Aquatic Conservation

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In ancient times, the distribution range of the Mediterranean monk seal (Monachus monachus) extended all over the coasts of the Mediterranean, the Black Sea and parts of the north‐eastern Atlantic coast. Nowadays, the species is classified as Endangered and the current total world population is stated to consist of ~700 animals, though numbers mostly express best estimates. Distribution patterns in documents of international authorities from the last 15 years indicate the species' extinction in a number of Mediterranean countries, whereas in some of them only a few individuals are thought to survive and in others the status is unknown. This study analyses recent monk seal sightings over the period from 2000 to 2014 in the Mediterranean Basin. The locations of the sightings cover most of the study area and indicate a spreading of individual seals or a more stable presence in regions where the species was considered extinct. The investigation pointed out that efforts for the protection of monk seals, the most endangered marine mammal in Europe, should encompass all areas where monk seal sightings have been recorded, including the protection and conservation of potential suitable habitats in countries where the species apparently no longer exists. Appropriate conservation measures, such as the establishment of marine protected areas and sustainable management of fisheries, will aid natural recolonization and enhance gene flow between distant regions throughout the Mediterranean Basin, allowing the reconnection of distant populations or individual animals.

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Mid-distance re-sighting of a common bottlenose dolphin in the northern Adriatic Sea: insight into regional movement patterns

Cited by 13 publications

References 41 publications

Behavioural and temporal partitioning of dolphin social groups in the northern Adriatic Sea

Behavioural and temporal partitioning of dolphin social groups in the northern Adriatic Sea

Linking organochlorine contaminants with demographic parameters in free-ranging common bottlenose dolphins from the northern Adriatic Sea

On sightings of (vagrant?) monk seals, Monachus monachus, in the Mediterranean Basin and their importance for the conservation of the species

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