PelaSIG, a QGIS plugin for marine megafauna census: application to the aerial ACCOBAMS Survey Initiative dataset

Nivière, Manon; Blanchard, Ariane; Jraifi, Oussama; Van Canneyt, Olivier; Dorémus, Ghislain; Spitz, Jérôme; Mansoux, Bruno; Panigada, Simone; Laran, Sophie

doi:10.3389/fmars.2023.1270335

Cited by 2 publications

(3 citation statements)

References 16 publications

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“…Before performing density and abundance estimation analysis, data were used to provide explorative descriptive statistics and calculation of encounter rates (sightings per unit of effort), using a grid cell of 50x50 km, through a dedicated plugin PelaSIG. The results of this exploratory analyses and the details on the plugin are presented in Nivière et al (2024).…”

Section: Discussionmentioning

confidence: 99%

“…Habitat loss and fragmentation, alongside the indirect effects of overfishing, unintentional captures during fishing operations, and take, have strongly contributed to the decline of dolphin numbers across the entire region (e.g., Bearzi et al, 2003;Bearzi et al, 2004;Bearzi et al, 2008;Cañadas and Vaźquez, 2017;Mussi et al, 2019). Overall, 32 primary sightings of common dolphins, mostly in the western portion of the basin and in the Strait of Sicily (see Nivière et al, 2024), were recorded during the ASI aerial surveys, with a total estimate of 66,359 individuals (95% CI=31,054 -141,801).…”

Section: Striped Dolphin Common Dolphin and Striped/common Dolphin Guildmentioning

confidence: 99%

“…In addition, information on the presence, distribution, and levels of human activities (e.g., floating macro-marine litter, marine traffic, etc.) was collected (Lambert et al, 2020;Nivière et al, 2024).…”

Section: Introductionmentioning

confidence: 99%

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The ACCOBAMS survey initiative: the first synoptic assessment of cetacean abundance in the Mediterranean Sea through aerial surveys

Panigada,

Pierantonio,

Araújo

et al. 2024

Front. Mar. Sci.

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The “ACCOBAMS Survey Initiative” (ASI) is a pilot programme aimed at establishing an integrated and coordinated monitoring system for cetaceans across the Agreement on the Conservation of Cetaceans of the Black Sea, Mediterranean Sea and contiguous Atlantic (hereafter “ACCOBAMS”) area. Conducted in coordination with Mediterranean coastal countries, it supports the implementation of European and regional policies, in particular the EU Marine Strategy Framework Directive and the Ecosystem Approach process. In summer 2018, a synoptic survey was conducted across the Mediterranean Sea and contiguous Atlantic area, combining visual monitoring from aircrafts with visual and passive acoustic monitoring from vessels. Species density and abundance were estimated through design-based approach in a line-transect sampling framework. Based on data arising from the aerial survey only, uncorrected design-based abundance was obtained for striped (N=426,744, CV=0.13), common (N=65,359, CV=0.4), bottlenose (N=63,333, CV=0.17), and Risso´s dolphins (N=26,006, CV=0.3), Cuvier’s beaked whales (N=2,929, CV=0.4) and long-finned pilot whales (N=5,540 CV=0.4). A merged category of either striped or common dolphins resulted in 212,483 individuals (CV=0.26). Fin whales abundance of 1,749 animals (CV=0.3) was corrected for both availability and perception biases and resulted in 3,282 (CV=0.31). The ASI survey offers an overall picture of the distribution and abundance of cetaceans throughout the Mediterranean basin, providing robust estimates to be considered as a baseline for future regional systematic monitoring programmes. The ASI survey is the first step towards establishing a long-term monitoring program across the entire ACCOBAMS area, and, as such, it sets the basis for further future basin-wide monitoring efforts using systematic, shared, coordinated and comparable methods. The information gathered will further enhance knowledge on cetacean status, facilitating the development of informed conservation and mitigation measures, as well as supporting the implementation of international obligations. Furthermore, the outcomes of this survey will support both place- and threat-based conservation efforts in the ACCOBAMS area, through the identification of Important Marine Mammal Areas and Cetacean Critical Habitats. Here the results of the ASI survey are presented and discussed alongside proposed management and conservation actions aimed at ensuring the persistence of cetacean populations in the region.

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Section: Discussionmentioning

confidence: 99%

Section: Striped Dolphin Common Dolphin and Striped/common Dolphin Guildmentioning

confidence: 99%

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The ACCOBAMS survey initiative: the first synoptic assessment of cetacean abundance in the Mediterranean Sea through aerial surveys

Panigada,

Pierantonio,

Araújo

et al. 2024

Front. Mar. Sci.

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From the sky and on the beaches: complementary tools to evaluate common dolphin bycatch in the Bay of Biscay

Peltier,

Laran,

Dabin

et al. 2024

Endang. Species. Res.

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Since 1989, multiple stranding events of common dolphins have been regularly recorded along the French Atlantic coast. Examination of the carcasses revealed that most animals presented evidence of bycatch. Using stranding data to infer bycatch levels reveals the highest levels of bycatch to have been recorded since 2016 (4000 to 9000 bycaught individuals). This approach is directly influenced by drift conditions, which can greatly contribute to or hinder our ability to estimate bycatch at sea. In the winter of 2021/2022, the French stranding network recorded an unusually high number of strandings until mid-February and few records in March. Investigation of drift conditions revealed low probability of stranding in March due to constant east-west winds. Reverse drift modelling of carcasses stranded in January and February resulted in an estimate of 3670 (95% CI [2750; 5170]) bycaught common dolphins. Dedicated aerial surveys were conducted in the same area during this period, designed to assess abundance and distribution of marine megafauna in French waters. A high number of carcasses of small Delphininae were observed in March 2021, and the number of carcasses floating at sea could be estimated using conventional distance sampling methodology. In March 2021, mortality at sea was thus estimated at 3250 (95% CI [1288;10198]) common dolphins. The complementary use of both methodologies resulted in an estimate of 6920 (95%CI [4038;15368]) bycaught individuals during winter 2021/2022. This case study highlights that a decrease in strandings does not imply a decrease in mortality at sea. Trends in strandings need to be considered in the light of scientific evidence to avoid delays in decision making.

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PelaSIG, a QGIS plugin for marine megafauna census: application to the aerial ACCOBAMS Survey Initiative dataset

Cited by 2 publications

References 16 publications

The ACCOBAMS survey initiative: the first synoptic assessment of cetacean abundance in the Mediterranean Sea through aerial surveys

The ACCOBAMS survey initiative: the first synoptic assessment of cetacean abundance in the Mediterranean Sea through aerial surveys

From the sky and on the beaches: complementary tools to evaluate common dolphin bycatch in the Bay of Biscay

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