Spatio-temporal surveys of the brown meagre Sciaena umbra using passive acoustics for management and conservation

Abstract

20Conservation of exploited fish populations is a priority for environmental managers. Spatio-21 temporal knowledge on reproductive sites is mandatory for species and habitat conservation but 22 is often difficult to assess, particularly over vast geographic areas. Regular and long-term 23 standardized surveys are necessary to identify reproductive sites, assess population trends and 24 their distribution. Here we emphasize the utility of Passive Acoustic Monitoring (PAM) for the 25 survey and management of a depleted vulnerable Mediterranean fish species, the brown meagre, 26 Sciaena umbra. Acoustic surveys of reproductive calls were conducted combining 1) spatial 27 data from standardized surveys within three MPAs and from 49 unprotected sites throughout 28 the Northwestern Mediterranean basin, as well as 2) temporal data from a two-year-long survey 29 at a presumed spawning location. The MPA surveys, which rapidly scanned ~30-50 km of the 30 rocky coastlines per MPA, unveiled maps of distribution and reproductive activity of the brown 31 meagre, including potential spawning sites. They were also effective in emphasizing effects 32 linked to management actions: Full-protection zones had a higher number of vocalizations (70% 33 of the listening sites) compared to less protected zones (30% of the sites) or sites outside MPAs 34 (45% of the sites). This was also reflected in the number of singers that was generally low (< 3 35 individuals) in less protected zones and outside MPAs, implying lower fish densities. Highest 36 calling aggregations were observed in potential spawning areas that represented only 0.04% of 37 all listening sites, and were almost all in older, fully protected MPAs, which thus play a key 38 role for fish stock recovery. The two-year survey revealed a 5-month reproductive season (from 39 May to October) with a strong positive correlation between calling activity and temperature.40Overall this study confirms the role of PAM as an efficient, replicable and standardized non-41 invasive method for population management that can identify functional sites and key 42 protection zones, provide valuable information on reproduction, spatial and temporal 43 occurrence, but also on population trends and climate-driven changes. 44 3 45 46

Sound discrimination of two sympatric, threatened fish species allows for their in situ mapping

“…Given that these species are vocally active during reproduction, PAM represents a non-invasive technique to achieve these goals over yearly temporal and vast basin spatial scales (ie. the north-western Mediterranean; Di Iorio et al, 2020). This is the first case in which two sciaenid species have been documented to share their reproductive habitat in the Mediterranean Sea, as is the case for many other sciaenids inhabiting the Atlantic coast (Holt & Holt, 2000;Soares & Vazzoler, 2001;Monczak et al, 2017;Monczak et al, 2019).…”

“…Similarly, along the Atlantic coast, sympatric sciaenids have been discriminated and located at sea thanks to their vocalizations; however, their degree of inter-specific difference appears greater than that characterizing shi drum and brown meagre sounds (Sprague et al, 2000;Luczkovich et al, 2008;Monczak et al, 2017;Monczak et al, 2019). The proposed characterization of shi drum sounds allows for its acoustic monitoring at sea, as is already the case for the brown meagre (Picciulin et al, 2016;Parmentier et al, 2018;Di Iorio et al, 2020).…”

“…In aquaculture facilities, shi drum calls are emitted at significantly higher rates during spawning nights, when temporal features can provide information on the onset of reproduction (Bolgan et al, 2020a). In contrast, the presence of the brown meagre has been widely monitored by PAM in several coastal areas of the Mediterranean Sea (Bonacito et al, 2002;Picciulin et al, 2013;Colla et al, 2018;Parmentier et al, 2018;Desiderà et al, 2019;Di Iorio et al, 2020), where choruses provide a reliable natural indicator of this species' breeding sites (Picciulin et al, 2020).…”

Fish acoustic community structure in Neptune seagrass meadows across the Mediterranean basin

“…Previous studies have shown that at least three vocal fish taxa are typically present in this habitat, namely Ophidion rochei (Müller, 1845), Sciaena umbra (Linnaeus, 1758) and Scorpaena spp. (Linnaeus, 1758) (Ceraulo et al, 2018; Di Iorio et al, 2018; Bolgan et al, 2019; Di Iorio et al, 2020). Ophidion rochei , an endemic Mediterranean fish inhabiting sandy areas and patchy seagrass meadows, presents extensive anatomical modifications related to sound production abilities (Dulčić et al, 2002; Keskin, 2007; Parmentier et al, 2010; Kéver et al, 2012).…”

“…Ophidion rochei , an endemic Mediterranean fish inhabiting sandy areas and patchy seagrass meadows, presents extensive anatomical modifications related to sound production abilities (Dulčić et al, 2002; Keskin, 2007; Parmentier et al, 2010; Kéver et al, 2012). Sciaena umbra , a small‐sized, demersal sciaenid inhabiting rocky bottoms and Posidonia beds, was the first fish species to be monitored by its communicative sounds in the Mediterranean Sea (Bonacito et al, 2002; Alós & Cabanellas‐Reboredo, 2012; Picciulin et al, 2012; Picciulin et al, 2013; Parmentier et al, 2018; Di Iorio et al, 2020; Picciulin et al, 2020). Scorpaena spp.…”