Spatial distribution modelling of striped dolphin (Stenella coeruleoalba) at different geographical scales within the EU Adriatic and Ionian Sea Region, central‐eastern Mediterranean Sea

Abstract

The striped dolphin (Stenella coeruleoalba) is one of the most abundant cetaceans of the Mediterranean Sea. Nevertheless, it is ranked as ‘Vulnerable’ by IUCN Red List experts. To implement conservation strategies within the Mediterranean Sea, it is crucial to understand how striped dolphins are distributed at different geographical scales. The present study investigates its distribution within the EU Adriatic and Ionian Sea Region. To model striped dolphin distribution, topographic (distance from shore, depth and slope) and oceanographic variables (sea surface temperature and phytoplankton concentration) were employed, and species distribution models (SDMs) were developed using Maxent software. Generalized additive models (GAMs) were used to improve the information supplied by the SDMs, allowing the description of response curves to striped dolphin occurrences. Statistical analysis shows that striped dolphins are not evenly distributed within the investigated area. The higher encounter rates observed in the Gulf of Taranto and the Gulf of Corinth confirm that both sub‐regions are crucial for its conservation. Furthermore, SDMs also indicate suitable areas in the offshore waters of the Adriatic Sea, along the continental slope of the north‐eastern Ionian Sea and over its continental shelf. Within the EU Adriatic and Ionian Sea Region, striped dolphins prefer areas at a greater distance from shore, with steeper slopes, deeper waters, and higher sea surface temperature. The topographic variables are the most explicative factors for both modelling approaches. The analysis of striped dolphin SDMs allows the identification of important areas for conservation and highlights zones where appropriate mitigation strategies could reduce the impact of human activities on this Vulnerable species. Further analysis of SDMs for different periods of the year, as well as a genetic study, could highlight seasonal movements across and within sub‐regions.

Assessment of cetacean–fishery interactions in the marine food web of the Gulf of Taranto (Northern Ionian Sea, Central Mediterranean Sea)

“…Although the Gulf of Taranto is characterized by a marked anthropogenic presence and intense fishing exploitation (Carlucci et al 2016), the occurrence of cetacean species, such as the striped dolphin (Stenella coeruleoalba), the common bottlenose dolphin (Tursiops truncatus), the Risso's dolphin (Grampus griseus), the sperm whale (Physeter macrocephalus) and the fin whale (Balaenoptera physalus) makes this area eligible for the establishment of a Specially Protected Area of Mediterranean Importance (SPAMI), according to the SPA/BD Protocol (Carlucci et al 2018b, c;Maglietta et al 2018;Azzolin et al 2020). In particular, the striped and common bottlenose dolphins are the most frequent and abundant species distributed throughout the Gulf of Taranto (Carlucci et al 2016(Carlucci et al , 2018b.…”

The Social Role of Vocal Complexity in Striped Dolphins

“…A narrow continental shelf with a steep slope and several channels characterizes the western sector, while the eastern sector shows descending terraces toward the "Taranto Valley, " a NW-SE submarine canyon with no clear bathymetric connection to a major river system (Capezzuto et al, 2010;Russo et al, 2017;Carlucci et al, 2018a). The striped dolphin regularly occurs in the northernmost portion of the Taranto Valley (Azzolin et al, 2020), most likely attracted by the high productivity of the sub-marine canyon system and its upwelling currents (Carlucci et al, 2018c).…”

Trends in summer presence of fin whales in the Western Mediterranean Sea Region: new insights from a long-term monitoring program

“…The use of ferries as platforms for conducting dedicated research has been increasing in recent years. It has been demonstrated that data collection following specific protocols can result in the successful use of the data for species distribution studies ( Kiszka et al, 2007 ; Arcangeli, Marini & Crosti, 2012 ; Aïssi et al, 2015 ; Correia et al, 2015 ; Morgado et al, 2017 ; Azzolin et al, 2020 ).…”