1 – THE CUVIER’S BEAKED WHALE AND IMPULSIVE NOISE
The Mediterranean population of Cuvier’s beaked whales comprises about 5,800 individuals (Cañadas et al. 2018) and is listed as Vulnerable by the IUCN Red List (Cañadas and Notarbartolo di Sciara 2018). The importance of the Pelagos Sanctuary for the Mediterranean population of Cuvier’s beaked whale (Ziphius cavirostris) is highlighted in various sources. In 2016, the IUCN reiterated the importance of the Sanctuary for this species by identifying the Important Marine Mammal Area (IMMA) of the Western Ligurian Sea and Genoa Canyon, which identifies Cuvier’s beaked whale critical habitats in this area. Podestà et al. 2016 (Figure 1) also summarised knowledge on the distribution and residence of the species showing that two out of the five important areas for this species Mediterranean population are located within the Sanctuary. These two areas are used by at least 400 individuals (Massimiliano Rosso, CIMA Foundation photo-identification database).
Beaked whales are known to be sensitive to a wide range of man-made noise (Aguilar de Soto et al. 2006). In particular, they have a negative reaction to a class of impulsive noises, especially those produced by military anti-submarine sonars. These types of noises are believed to provoke abrupt behavioural responses that affect their normal diving behaviour resulting in lethal “decompression sickness” leading to mass strandings. In some cases, exposure to these high energy sounds can cause direct injuries to fundamental tissues (for a review, see Bernaldo de Quiros et al. 2019). The link between military sonars and mass strandings of beaked whales was first suggested in 1996 in Greece, where an atypical event of this kind occurred near a military exercise area (Frantzis 1998). This event was brought to global attention, stimulating major scientific efforts especially by the NATO Underwater Research Center (NURC). They found that cetacean responses to military sonar varied by species and areas, but confirmed that in the Mediterranean case the deadly correlation between military exercises and mass strandings was significant for Cuvier’s beaked whales (Filadelfo et al. 2009). In this regard, NURC also drew up its own “Marine Mammal Risk Mitigation Rules and Procedures” (2009).
In 2013, the Scientific Committee of the Agreement on the Conservation of Cetaceans of the Black Sea, Mediterranean Sea and Contiguous Atlantic Area (ACCOBAMS) underlined that “during naval exercises using sonar or underwater explosions, there should be absolute avoidance within an approximate 90 km buffer zone around all areas that have been designated as ‘Areas of Special Concern for Beaked Whales’ in the Mediterranean Sea” (Rec. 8.6 of the ACCOBAMS Scientific Committee). At present, the best available map that represents the “Areas of Special Concern” for this species is the one in Figure 2 (source: Cañadas et al. 2018). This map reiterates the importance of the Pelagos Sanctuary and surrounding regions (dark areas).
Figure 2. Distribution of Mediterranean Cuvier’s beaked whales (Source: Cañadas et al. 2018)
2 – LEGAL CONTEXT OF THE AGREEMENT AND MEASURES ADOPTED AT A NATIONAL LEVEL
The legal context in which Pelagos Parties operate on the effects of military impulsive noise on Cuvier’s beaked whales is clarified by the text of the Pelagos Agreement (Table 1). This also provides guidance on how the Parties should ensure full consistency between the legitimate ‘sovereign immunity’ and the Agreement’s overall objective, i.e. “to guarantee a favourable conservation status of marine mammals by protecting them and their habitat, from direct or indirect negative impacts of human activities” (see art. 15 and 4, respectively).