Maritime traffic trends around the southern tip of Africa – Did marine noise pollution contribute to the local penguins' collapse?

Pichegru, Lorien; Vibert, Laëtitia; Thiebault, Andréa; Charrier, Isabelle; Stander, Nicky; Ludynia, Katta; Lewis, Melissa A.; Carpenter-Kling, Tegan; McInnes, Alistair

doi:10.1016/j.scitotenv.2022.157878

Cited by 14 publications

(4 citation statements)

References 62 publications

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“…Noise occurrence in oceans has dramatically increased since the industrial age, with increasing shipping activity resulting in an estimated 32-fold increase in low frequency noise over the last 50 years [ 21 ]. Anthropogenic noise can impact all forms of marine life, from fishes and invertebrates [ 22 ] to marine predators, such as cetaceans [ 23 ] and seals [ 24 ], and diving and flying seabirds [ 25 , 26 ]. Reported impacts range from fatal strandings, hearing damage (temporary or permanent), avoidance of noisy areas, change and interference in behaviors (e.g., foraging, breeding, socializing) to vocal/hearing masking [ 23 , 27 ].…”

Section: Introductionmentioning

confidence: 99%

First Description of the Underwater Sounds in the Mediterranean Monk Seal Monachus monachus in Greece: Towards Establishing a Vocal Repertoire

Charrier

Huetz

Prevost

et al. 2023

Animals

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The Mediterranean monk seal Monachus monachus is one of the most endangered pinnipeds in the world, and is classified as “Endangered” by the International Union for the Conservation of Nature. Any additional knowledge about the species is invaluable to its effective conservation. In the present study, we deployed an autonomous underwater recorder in an important reproductive area of the Mediterranean monk seal in Greece to describe its underwater vocal repertoire. Over the 330 h of continuous recordings, 9231 vocalizations were labelled as potentially produced by Mediterranean monk seals, and 1694 good quality calls were analyzed. We defined 18 call types divided into three main call categories: harmonic, noisy, and pulsative calls. We also described the soundscape in which this endangered species lives and found that human activities around the two main pupping caves had a strong impact on the sonic environment of these seals: the noise level produced by boat traffic was high, and occurred on an hourly (25 to 50 min/hour) and daily basis (10.8 to 16.9 h/day). Such high levels of noise might not only impair the communication of the species, but also impact its survival, as chronic noise can induce physiological stress.

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Section: Introductionmentioning

confidence: 99%

First Description of the Underwater Sounds in the Mediterranean Monk Seal Monachus monachus in Greece: Towards Establishing a Vocal Repertoire

Charrier

Huetz

Prevost

et al. 2023

Animals

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“…In contrast, about 1 in 6 of all vessel transits, or 16%, were identified as being ‘noisy’. Although our classification of vessels in this category was a subjective one, this preliminary result is worth consideration given that noise is a specific component of vessel disturbance in aquatic systems [ 45 ], and marine birds may respond to noise as a disturbance [ 35 , 36 , 46 ]. While effects of vessel noise alone has so far not been well studied in the context of waterbird responses [ 3 ], it has been explicitly described as a supposed component of overall vessel disturbance effects (e.g., [ 7 , 47 , 48 ]).…”

Section: Discussionmentioning

confidence: 99%

“…We used known length ranges of vessel brands, and on-deck objects such as dinghies, paddles, and people to help calibrate our estimates of vessel length, ‘Knots’ and ‘feet’ were used as the measurement units for estimated speed and length given our visual familiarity with these standard nautical measurements. As waterbirds may be sensitive to ambient sound [ 35 , 36 ], we also classified vessels as ‘noisy’ or not, based on subjective impressions of vessel engine noise. ‘Noisy’ vessels were not simply those running motors, but, for example, were those operated at a volume that would impede normal conversation for people travelling on board.…”

Section: Methodsmentioning

confidence: 99%

Visual surveys provide baseline data on small vessel traffic and waterbirds in a coastal protected area

2023

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The coastal waters of southern British Columbia, Canada, encompass habitat of international conservation significance to coastal and marine birds, including sizeable areas designated in the early 1900s as Migratory Bird Sanctuaries (MBS) to protect overwintering waterfowl from hunting near urban centres. Two of these, Shoal Harbour (SHMBS) and Victoria Harbour (VHMBS), have seen significant marine infrastructure development in recent decades and experience considerable vessel traffic. Vessel-related stressors are known to affect waterbirds, but traffic characteristics in coastal urban areas are poorly understood for the smaller vessels not tracked by Automatic Identification Systems (AIS). We conducted a pilot study using shore-based observers to develop small-vessel baselines for the winter months, when regional waterbird numbers are highest. During our surveys we recorded considerable inter-site variability in vessel traffic characteristics, with one site (SHMBS) a source of nearly twice as many vessel transits as the other (VHMBS). Most recorded vessels were small watercraft (mean length 26 ± 17′, mode 18′), and vessels at the high-traffic site were both shorter and faster on average. One in six vessels were classified as ‘noisy’, of interest given that noise is an important component of vessel disturbance of waterbirds and other marine animals. Few vessels (7% of all recorded) were of the type required to carry AIS transponders, which highlights the monitoring gap created by using AIS-based approaches alone in nearshore waters, and allows for correction of AIS-derived vessel counts. Waterbird community composition also varied by locality, with one site dominated by gulls (Laridae), cormorants (Phalacrocoracidae), and seaducks (Tribe Mergini), and the other by gulls, cormorants, and alcids (Alcidae). Our results demonstrate that fine-scale local variability must be taken into account when managing for vessel traffic disturbance of waterbirds, particularly at sites of high human population density and increasing coastal development.

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“…Recently, three penguin species have been internationally voted as highest priority for conservation efforts [ 24 ]; one of which, the African penguin ( Spheniscus demersus ), is characterised by a largely depleted population [ 23 ], with many island colonies subject to drastic declines and collapses, and only two mainland colonies across South Africa [ 25 , 26 ]. Both individual survival and colony breeding success are strongly impacted by habitat loss owing to resource competition with industrial fisheries, the expansion of anthropogenic activities, and marine noise pollution [ 26 , 27 , 28 , 29 ]. Moreover, the negative consequences of oil spills alone may be sufficient to lead to the extinction of the African penguin [ 27 , 30 , 31 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of Environmental Variables on African Penguin Vocal Activity: Implications for Acoustic Censusing

Hacker,

Terranova,

Petersen

et al. 2023

Biology

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Global biodiversity is in rapid decline, and many seabird species have disproportionally poorer conservation statuses than terrestrial birds. A good understanding of population dynamics is necessary for successful conservation efforts, making noninvasive, cost-effective monitoring tools essential. Here, we set out to investigate whether passive acoustic monitoring (PAM) could be used to estimate the number of animals within a set area of an African penguin (Spheniscus demersus) colony in South Africa. We were able to automate the detection of ecstatic display songs (EDSs) in our recordings, thus facilitating the handling of large datasets. This allowed us to show that calling rate increased with wind speed and humidity but decreased with temperature, and to highlight apparent abundance variations between nesting habitat types. We then showed that the number of EDSs in our recordings positively correlated with the number of callers counted during visual observations, indicating that the density could be estimated based on calling rate. Our observations suggest that increasing temperatures may adversely impact penguin calling behaviour, with potential negative consequences for population dynamics, suggesting the importance of effective conservation measures. Crucially, this study shows that PAM could be successfully used to monitor this endangered species’ populations with minimal disturbance.

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Maritime traffic trends around the southern tip of Africa – Did marine noise pollution contribute to the local penguins' collapse?

Cited by 14 publications

References 62 publications

First Description of the Underwater Sounds in the Mediterranean Monk Seal Monachus monachus in Greece: Towards Establishing a Vocal Repertoire

First Description of the Underwater Sounds in the Mediterranean Monk Seal Monachus monachus in Greece: Towards Establishing a Vocal Repertoire

Visual surveys provide baseline data on small vessel traffic and waterbirds in a coastal protected area

Effect of Environmental Variables on African Penguin Vocal Activity: Implications for Acoustic Censusing

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