Monitoring Winter and Summer Abundance of Cetaceans in the Pelagos Sanctuary (Northwestern Mediterranean Sea) Through Aerial Surveys

Abstract

Systematic long-term monitoring of abundance is essential to inform conservation measures and evaluate their effectiveness. To instigate such work in the Pelagos Sanctuary in the Mediterranean, two aerial surveys were conducted in winter and summer 2009. A total of 467 (131 in winter, 336 in summer) sightings of 7 species was made. Sample sizes were sufficient to estimate abundance of fin whales in summer (148; 95% CI = 87–254) and striped dolphins in winter (19,462; 95% CI = 12 939–29 273) and in summer (38 488; 95% CI = 27 447–53 968). Numbers of animals within the Sanctuary are significantly higher in summer, when human activities and thus potential population level impacts are highest. Comparisons with data from past shipboard surveys suggest an appreciable decrease in fin whales within the Sanctuary area and an appreciable increase in striped dolphins. Aerial surveys proved to be more efficient than ship surveys, allowing more robust estimates, with smaller CIs and CVs. These results provide essential baseline data for this marine protected area and continued regular surveys will allow the effectiveness of the MPA in terms of cetacean conservation to be evaluated and inform future management measures. The collected data may also be crucial in assessing whether ship strikes, one of the main causes of death for fin whales in the Mediterranean, are affecting the Mediterranean population.

Crowdsourcing Modern and Historical Data Identifies Sperm Whale (Physeter macrocephalus) Habitat Offshore of South-Western Australia

“…Traditional line-transect surveys estimating abundance would search across depths (Buckland et al, 2001;Mellinger and Barlow, 2003;Barlow and Taylor, 2005; Panigada et al, 2011;Pirotta et al, 2011). However, because the principal goal of the RV Odyssey work was to get biopsy samples, the RV Odyssey surveyed specifically along the −2000 to −3000 m isobaths.…”

Potential feeding habitat of fin whales in the western Mediterranean Sea: an environmental niche model

“…Furthermore, mobile animals may not use the entire suitable habitat at any one time (Boyce et al 2002); thus, it may be difficult to demonstrate non-use, especially in the case of small populations (ca. 3500 individuals in the western Mediterranean Sea; Forcada et al 1996, Panigada et al 2011. Lastly, in addition to the ecological knowledge taken into account, the spatial dimension of the model for optimizing the parameterization (distance to potential habitat as enhanced by Valavanis et al 2008) on a daily time scale and the ability to select optimal habitat size are key predictive elements which are not present in most regression models.…”

Isotopic niches of fin whales from the Mediterranean Sea and the Celtic Sea (North Atlantic)

“…1a) was estimated at 715 individuals (CV ¼ 31.2%) (Gannier, 2006). Surveys carried out in summer 2009 in the Pelagos Sanctuary estimated abundance of fin whales at 148 (95% CI ¼ 87e254), pointing towards an appreciable decrease in summer abundance and density since the early 1990s (Panigada et al, 2011). Studies on Mediterranean fin whales feeding habits inferred from surface feeding visual observations from stomach content and faeces analyses suggested that the euphausiid Meganyctiphanes norvegica is the main food item in the western Mediterranean Sea (Canese et al, 2006;Notarbartolo-di-Sciara et al, 2003;Orsi Relini and Giordano, 1992).…”