Reduction in Body Mass and Blubber Thickness of Harbor Porpoises (Phocoena phocoena) Due to Near-Fasting for 24 Hours in Four Seasons

Kastelein, Ronald A.; Helder-Hoek, Lean; Jennings, Nancy; Kester, Ruby van; Huisman, Rowanne

doi:10.1578/am.45.1.2019.37

Cited by 23 publications

(23 citation statements)

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“…The ability to potentially quantify foraging behaviour (and potentially other types of behaviour) opens a range of new opportunities to obtain answers to some pending questions. As an example, if feeding buzzes can be translated into foraging activity of harbour porpoises at sea, this information could be compared with data on physiology and feeding behaviour of captive porpoises (SEAMARCO) to better assess the impact (on an individual an population level) of interrupted foraging (Kastelein et al 2019).…”

Section: Resultsmentioning

confidence: 99%

“…The general assumption right now is that a reduction in feeding could have a negative impact on porpoise survival. Some limited data on feeding budgets is available from animals held in captivity (Kastelein et al, 1997(Kastelein et al, , 2019, as well as from recent tagging results (Wisniewska et al, 2016). However, on what scale feeding activities might be disrupted due to human activity is still unclear.…”

Section: Introductionmentioning

confidence: 99%

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Quantifying harbour porpoise foraging behaviour in CPOD data: identification, automatic detection and potential application

Bergès¹,

D.²,

Geelhoed³

et al. 2019

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Harbour porpoise foraging behaviour 2.3 Gemini Offshore Wind Farm 2.4 CPOD data collection 3 Method 3.1 Click train based methods 3.2 Click based methods 4 Results and discussion 4.1 Identification of foraging behaviour 4.1.1 Click train based methodology 4.1.2 Click based methodology 4.2 Methods for automated detection of foraging/feeding events 4.2.1 Methodology comparison 4.2.2 Buzz clicks detection algorithm 4.3 Application to Gemini data 4.3.1 Changes over time and between stations 4.3.2 Relation to pile driving activities 4.4 Limitations 5 Conclusions and recommendations 5.1 Conclusions 5.2 Recommendations 6 Acknowledgments 7 Quality Assurance References Annex I: additional results Justification Wageningen Marine Research report C039/19| 4 of 41 Summary Harbour porpoises (Phocoena phocoena) are regularly monitored to assess how they are impacted by the construction and operation of offshore wind farms. A suitable method to do this is passive acoustic monitoring (PAM), and in particular using specific stationary hydrophones called CPODs. These devices provide information on click activity, which can then be analysed to investigate habitat use over time, differences between areas and the impact of human activities. Due to their small size and high metabolism porpoises are thought to need a more or less constant supply of prey to survive. Prey occurrence is thus considered one of the main drivers in porpoise distribution. And successful feeding is vital to the fitness and survival of individual porpoises. Information on foraging behaviour, however, is difficult to obtain in the field, in particular as animals feed under water. Recently the tagging of animals has provided new insights into porpoise behaviour, but it has been done for a limited number of individuals and for short times only. CPOD data have been used in Dutch waters to monitor harbour porpoise habitat use and behaviour before, during and after the construction of wind farms. The analyses have focussed on using a number of parameters that can be derived from the data, such as porpoise positive minutes, hours or days, encounter and waiting times. From other studies, primarily in captivity, we know that during foraging porpoises produce a characteristic pattern of clicks, starting with an approach phase and ending with a so-called "terminal buzz". Aim of our study was to investigate if we could quantify foraging behaviour from CPOD data, and we were able to use an existing data set of harbour porpoise click activity from the Gemini wind park (June 2015 to February 2016). The study consisted of three phases. First, the different existing methods were applied to a sample set of data to determine the most suitable approach to identify foraging behaviour. The results indicate that re-classification of clicks following the method developed by Pirotta (2014 a,b) to identify terminal buzzes provides the best results. Second, an algorithm was written to allow the automated analyses of CPOD data following this method. Finally, this analytical tool was applie...

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Quantifying harbour porpoise foraging behaviour in CPOD data: identification, automatic detection and potential application

Bergès¹,

D.²,

Geelhoed³

et al. 2019

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“…Harbour porpoises have a limited capacity to store energy and may rapidly suffer from fasting (Kastelein & van Battum, 1990;Koopman et al, 1996Koopman et al, , 2002Lockyer 2007;MacLeod et al, 2007;Wisniewska et al, 2016;Kastelein et al, 2019). A recent diet assessment of dead stranded harbour porpoises collected along French and Belgian coasts between 2010 and 2013…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, this reduced food availability and the lower energy content of prey in the northern North Sea may have resulted in the southward shift of harbour porpoises in the North Sea. Harbour porpoises have a limited capacity to store energy and may rapidly suffer from fasting (Kastelein & van Battum, 1990; Koopman et al ., 1996, 2002; Lockyer, 2007; MacLeod et al ., 2007; Wisniewska et al ., 2016; Kastelein et al ., 2019). A recent diet assessment of dead stranded harbour porpoises collected along French and Belgian coasts between 2010 and 2013 indicates that in addition to the most abundant and widely distributed fish species present in the area, they were also preying significantly upon sardines, Sardina pilchardus (Mahfouz et al ., 2017).…”

Section: Discussionmentioning

confidence: 99%

Modelling fine-scale distribution and relative abundance of harbour porpoises in the Southern Bight of the North Sea using platform-of-opportunity data

Bouveroux¹,

Waggitt²,

Belhadjer³

et al. 2020

J. Mar. Biol. Ass.

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Over the last 25 years, the harbour porpoise (Phocoena phocoena) has made a significant return to the Southern Bight of the North Sea and the English Channel due to a shift in distribution from northerly regions. Although the ecological drivers of this return are unclear, this species faces multiple threats in the region, including by-catch and habitat degradation. Ferry-based surveys were conducted year-round between November 2011 and June 2014 to assess the influence of environmental parameters upon the spatiotemporal distribution and relative abundance of harbour porpoises in the Southern Bight of the North Sea. A total of 1450 sightings of harbour porpoises were recorded during the 100 round-trip surveys carried out between Dunkirk (France) and Dover (England). Inter-annual and monthly variations in group size were observed, with largest groups recorded in 2014 (mean = 2.02) and in January (mean = 2.32). The relative abundance showed significant seasonal variation, with peaks recorded during winter months. An inter-annual increasing relative abundance was recorded during the study period. There was a seasonally dependent association with environmental variables, particularly depth, seabed roughness and current speed. Finally, predictions suggest large increases of the relative abundance in offshore habitats during winter months and over the study period.

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“…Reductions in body mass as a result of fasting have been documented in migrating and breeding baleen whales 14 – 16 as well as captive harbor porpoises 17 . However, this metric is logistically difficult to obtain for free ranging odontocetes, yet represents a fundamental component of energetic-based approaches to estimating effects of disturbance, such as the Population Consequences of Disturbance (PCoD) model framework 18 .…”

Section: Introductionmentioning

confidence: 99%

Rapid weight loss in free ranging pygmy killer whales (Feresa attenuata) and the implications for anthropogenic disturbance of odontocetes

Currie¹,

Aswegen

Stack³

et al. 2021

Sci Rep

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Understanding the impacts of foraging disruptions to odontocete body condition is fundamental to quantifying biological effects of human disturbance and environmental changes on cetacean populations. Here, reductions in body volume of free-ranging pygmy killer whales (Feresa attenuata) were calculated using repeated measurements of the same individuals obtained through Unoccupied Aerial System (UAS)-photogrammetry during a prolonged disruption in foraging activity arising from a 21-day stranding event. Stranded individuals were used to verify UAS-derived volume and length estimates through 3D-imaging, water displacement, and post-mortem measurements. We show that (a) UAS estimates of length were within 1.5% of actual body length and UAS volume estimates were within 10–13% of actual volume, (b) foraging disruption resulted in a daily decrease of 2% of total body mass/day, and (c) pygmy killer whales can lose up to 27% of their total body weight within 17 days. These findings highlight the use of UAS as a promising new method to remotely monitor changes in body condition and animal health, which can be used to determine the potential effects of anthropogenic disturbance and environmental change on free-ranging odontocetes.

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Reduction in Body Mass and Blubber Thickness of Harbor Porpoises (Phocoena phocoena) Due to Near-Fasting for 24 Hours in Four Seasons

Cited by 23 publications

References 0 publications

Quantifying harbour porpoise foraging behaviour in CPOD data: identification, automatic detection and potential application

Quantifying harbour porpoise foraging behaviour in CPOD data: identification, automatic detection and potential application

Modelling fine-scale distribution and relative abundance of harbour porpoises in the Southern Bight of the North Sea using platform-of-opportunity data

Rapid weight loss in free ranging pygmy killer whales (Feresa attenuata) and the implications for anthropogenic disturbance of odontocetes

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