Blast injury on harbour porpoises (Phocoena phocoena) from the Baltic Sea after explosions of deposits of World War II ammunition

Siebert, Ursula; Stürznickel, Julian; Schaffeld, Tobias; Oheim, Ralf; Rolvien, Tim; Prenger‐Berninghoff, Ellen; Wohlsein, P.; Lakemeyer, Jan; Rohner, Simon; Schick, Luca Aroha; Groß, Stephanie; Nachtsheim, Dominik; Ewers, Christa; Becher, Paul; Amling, Michael

doi:10.1016/j.envint.2021.107014

Cited by 22 publications

(26 citation statements)

References 65 publications

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“…Infectious diseases can develop quickly, not being reflected in the blubber thickness or nutritional status of an individual ( Siebert et al, 2001 ; Siebert et al, 2007 ; Bodewes et al, 2015 ; Siebert et al, 2020 ). In addition, the origin of an animal (e.g., by-caught, euthanized or stranded) does not necessarily reflect the health status of the individual, as by-caught animals display large variety of infectious diseases and stranded individuals can be traumatized by anthropogenic activities ( Siebert et al, 2022 ). Therefore, standardized necropsies on the individuals from which blubber thickness values are derived are extremely important ( IJsseldijk et al, 2019 ).…”

Section: Discussionmentioning

confidence: 99%

Variation of blubber thickness for three marine mammal species in the southern Baltic Sea

et al. 2022

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Evaluating populational trends of health condition has become an important topic for marine mammal populations under the Marine Strategy Framework Directive (MSFD). In the Baltic Sea, under the recommendation of Helsinki Commission (HELCOM), efforts have been undertaken to use blubber thickness as an indicator of energy reserves in marine mammals. Current values lack geographical representation from the entire Baltic Sea area and a large dataset is only available for grey seals (Halichoerus grypus) from Sweden and Finland. Knowledge on variation of blubber thickness related to geography throughout the Baltic Sea is important for its usage as an indicator. Such evaluation can provide important information about the energy reserves, and hence, food availability. It is expected that methodological standardization under HELCOM should include relevant datasets with good geographical coverage that can also account for natural variability in the resident marine mammal populations. In this study, seasonal and temporal trends of blubber thickness were evaluated for three marine mammal species—harbor seal (Phoca vitulina), grey seal (Halichoerus grypus) and harbor porpoise (Phocoena phocoena)—resident in the southern Baltic Sea collected and investigated under stranding networks. Additionally, the effects of age, season and sex were analyzed. Seasonal variation of blubber thickness was evident for all species, with harbor seals presenting more pronounced effects in adults and grey seals and harbor porpoises presenting more pronounced effects in juveniles. For harbor seals and porpoises, fluctuations were present over the years included in the analysis. In the seal species, blubber thickness values were generally higher in males. In harbor seals and porpoises, blubber thickness values differed between the age classes: while adult harbor seals displayed thicker blubber layers than juveniles, the opposite was observed for harbor porpoises. Furthermore, while an important initial screening tool, blubber thickness assessment cannot be considered a valid methodology for overall health assessment in marine mammals and should be complemented with data on specific health parameters developed for each species.

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Section: Discussionmentioning

confidence: 99%

Variation of blubber thickness for three marine mammal species in the southern Baltic Sea

et al. 2022

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“…Establishing if a porpoise suffered from over-exposure to underwater noise, by examining the sensory cells of the organ of Corti, can usually only be done within 24-30 h after death (Morell et al, 2017b). Injuries in the auditory system following detonations of unexploded ordnance (UXO) can, however, be studied in porpoises in more advanced states of decomposition (Siebert et al, 2022). Despite frequent UXO detonations in the southern North Sea (von Benda-Beckmann et al, 2015), (micro) CT-scans of the auditory system are not routinely conducted in the Netherlands.…”

Section: Management Implicationsmentioning

confidence: 99%

“…Porpoises are impacted by fishery activities through accidental bycatch, with underwater entanglement hampering them from air breathing, and competition for food (Kirkwood et al, 1997;Leeney et al, 2008;Dolman et al, 2016). Also, chemical pollution from persistent organic pollutants (Pierce et al, 2008;Weijs et al, 2009;Jepson et al, 2016;van den Heuvel-Greve et al, 2021), and underwater noise pollution from shipping (Wisniewska et al, 2018), seismic surveys, and unexploded ordnance detonations (von Benda-Beckmann et al, 2015;Aarts et al, 2016;Siebert et al, 2022) are known threats. More recent concerns and emerging threats include habitat loss due to the rapid growth of offshore activities related to the construction of wind farms (Madsen et al, 2006;Gilles et al, 2009;Teilmann and Carstensen, 2012) and the broadscale effects of climate change, including habitat degradation and changes in food quality and quantity (Simmonds and Isaac, 2007;Burge et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Pathological findings in stranded harbor porpoises (Phocoena phocoena) with special focus on anthropogenic causes

et al. 2022

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Humans impact natural systems at an unprecedented rate. The North Sea is one of the regions in the world with the highest levels of anthropogenic activity. Here, the harbor porpoise (Phocoena phocoena) is an abundant species and is often regarded as an ecosystem sentinel. A post-mortem surveillance program was established in the Netherlands aimed at increasing knowledge of the effects of human activities on harbor porpoises. In this study, we describe the pathological findings related to anthropogenic and natural causes of death categories in 612 harbor porpoises that stranded between 2008 and 2019, and assess their relations to age, sex, season, and location. The largest anthropogenic category was bycatch (17%), with mainly juveniles affected and peak periods in March and September–October. Other, infrequently diagnosed anthropogenic causes of death were trauma (4%), largely most likely due to ship collisions, and marine debris ingestion and entanglement (0.3%). The risk of dying from anthropogenic causes was highest for juveniles. Lesions compatible with noise-induced hearing loss were investigated in carcasses which were fresh enough to do so (n = 50), with lesions apparent in two porpoises. Non-direct human-induced threats included infectious diseases, which were by far the largest cause of death category (32%), and affected mainly adults. Also, gray seal (Halichoerus grypus) attacks were a frequently assigned cause of death category (24%). There were more acute predation cases in the earlier study years, while porpoises with lesions that suggested escape from gray seal attacks were diagnosed more recently, which could suggest that porpoises adapted to this threat. Our study contributes to understanding porpoise health in response to persisting, new, emerging, and cumulative threats. Building up such knowledge is crucial for conservation management of this protected species.

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“…during the construction and operation of offshore wind farms (Dähne et al, 2013;Brandt et al, 2018;Graham et al, 2019), shipping (e.g. reviewed in Erbe et al, 2019) or the clearance of unexploded ordnance (von Benda-Beckmann et al, 2015;Siebert et al, 2022). Intense sound is also emitted during seismic explorations of the seafloor (e.g.…”

Section: Introductionmentioning

confidence: 99%

A Result of Accidental Noise Pollution: Acoustic Flowmeters Emit 28 kHz Pulses That May Affect Harbor Porpoise Hearing

et al. 2022

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Large rivers like the Elbe or the Weser are periodically entered by harbor porpoises of the North Sea. They may even move 97 km upstream to the port of Hamburg, where their presence is highest in spring. This migration is believed to be related to important anadromous prey species travelling upstream for spawning. An acoustic flowmeter in the port of Hamburg emits signals in the hearing range of harbor porpoises. The pulses have a duration of 0.2 ms, a peak frequency of 28 kHz, a source level of 210 dB re 1 µPa and an inter-pulse interval of 4.2 s. The signals are continuously emitted from both sides of the river at a location where the river is 400 m wide. We evaluated the potential of these signals to induce temporary threshold shift (TTS) in harbor porpoise hearing. Hearing tests with a harbor porpoise in human care were conducted to determine TTS onset. We modelled the acoustic field based on underwater noise measurements. The acoustic flowmeters emit pulses in a highly directional beam with a source level high enough for inducing TTS in harbor porpoises by a single exposure up to a distance of approximately 72 m. The received cumulative sound exposure levels for harbor porpoises travelling along the flowmeters are mainly dependent on the timing and distance to the sound source. Accordingly, a close approach to the flowmeter at the time of transmission should be prevented. This could be the case, if vessels force harbor porpoises to displace closer to the flowmeters. We therefore suggest to decrease acoustic flowmeter source levels. This case study emphasizes the need for a mandatory authorization process prior to the use of underwater sound for any purpose with potential effects on aquatic life. Such an authorization process should carefully consider potential effects for target and non-target species.

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Blast injury on harbour porpoises (Phocoena phocoena) from the Baltic Sea after explosions of deposits of World War II ammunition

Cited by 22 publications

References 65 publications

Variation of blubber thickness for three marine mammal species in the southern Baltic Sea

Variation of blubber thickness for three marine mammal species in the southern Baltic Sea

Pathological findings in stranded harbor porpoises (Phocoena phocoena) with special focus on anthropogenic causes

A Result of Accidental Noise Pollution: Acoustic Flowmeters Emit 28 kHz Pulses That May Affect Harbor Porpoise Hearing

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