scholarly journals Vertebral pattern variation in the North Sea harbor porpoise ( Phocoena phocoena ) by computed tomography

2020 ◽  
Author(s):  
Dorien S. Willems ◽  
Lonneke L. IJsseldijk ◽  
D. Hendrik N. Broek ◽  
Stefanie Veraa
Keyword(s):  
Computed Tomography ◽  
North Sea ◽  
Phocoena Phocoena ◽  
Harbor Porpoise ◽  
The North ◽  
The North Sea

scholarly journals Harbor Porpoise (Phocoena phocoena) Reaction to a 3D Seismic Airgun Survey in the North Sea

2020 ◽  
Vol 6 ◽  
Author(s):  
Joanna Sarnocińska ◽  
Jonas Teilmann ◽  
Jeppe Dalgaard Balle ◽  
Floris M. van Beest ◽  
Matthieu Delefosse ◽  
...  
Keyword(s):  
North Sea ◽  
3D Seismic ◽  
Phocoena Phocoena ◽  
Harbor Porpoise ◽  
The North ◽  
The North Sea

Harbour porpoises (Phocoena phocoena) in north-western France: aerial survey, opportunistic sightings and strandings monitoring

2009 ◽  
Vol 89 (5) ◽  
pp. 1045-1050 ◽  
Author(s):  
J.-L. Jung ◽  
E. Stéphan ◽  
M. Louis ◽  
E. Alfonsi ◽  
C. Liret ◽  
...  
Keyword(s):  
North Sea ◽  
Aerial Survey ◽  
Harbour Porpoise ◽  
Shallow Waters ◽  
Encounter Rate ◽  
English Channel ◽  
Phocoena Phocoena ◽  
The North ◽  
The North Sea ◽  
North Western

The harbour porpoise (Phocoena phocoena) is one of the common small cetaceans of European waters. This discreet and undemonstrative species is strongly represented throughout the cold waters of the northern hemisphere, and is the most abundant cetacean in the North Sea. In the last few years, some observations and studies indicate a shift of harbour porpoise distribution in European waters, from northern regions of the North Sea to the southern North Sea, English Channel and Celtic Sea. This shift may include a comeback around the coasts of France. Harbour porpoises inhabit shelf-waters and are often observed in shallow waters, conditions offered for instance by the coasts of Brittany in north-western France. We used opportunistic sightings, aerial survey and a ten-year strandings database to study the presence of harbour porpoises along the coasts of Brittany. Opportunistic sightings made by non-specialists did not confirm a strong presence of harbour porpoises along the Brittany coasts, most probably because of the undemonstrative behaviour of this cetacean. However, aerial survey and stranding analysis indicate that harbour porpoises have become natural inhabitants of the Brittany coasts once more: 68.6% of cetacean school sightings made during a 1578 km aerial survey of the Brittany coasts concerned harbour porpoises, with an encounter rate of 1.5 individuals per 100 km that peaked to 5.8 per 100 km to the top of the shallow waters of the south-western Western English Channel. The number of harbour porpoise strandings increased each year from 1997 to 2007, making a total of 135 along the coasts of Brittany. Other cetaceans did not show such an increase during the same period. Strandings of harbour porpoises were also characterized by an apparent increase as a proportion in relation to all the cetacean strandings during the months of September to January, by a marked impact of by-catch during winter, and by an almost total absence of stranded calves. The comeback of the harbour porpoise along Brittany coasts is clearly confirmed by our data, and a stable population seems to be established again along the coasts of Brittany. This tends to confirm the shift of the distribution of the species in certain European waters. Long term monitoring, diet and genetic studies are now planned for a better understanding of this shift, and for the effective implementation of a conservation plan.

Identification of the first harbour porpoise (Phocoena phocoena) calving ground in the North Sea

1999 ◽  
Vol 41 (3) ◽  
pp. 225-232 ◽  
Author(s):  
R.P Sonntag ◽  
H Benke ◽  
A.R Hiby ◽  
R Lick ◽  
D Adelung
Keyword(s):  
North Sea ◽  
Harbour Porpoise ◽  
Phocoena Phocoena ◽  
The North ◽  
The North Sea

scholarly journals Diel echolocation activity of harbour porpoises (Phocoena phocoena) around North Sea offshore gas installations

2009 ◽  
Vol 66 (4) ◽  
pp. 734-745 ◽  
Author(s):  
Victoria L. G. Todd ◽  
William D. Pearse ◽  
Nick C. Tregenza ◽  
Paul A. Lepper ◽  
Ian B. Todd
Keyword(s):  
North Sea ◽  
Gas Production ◽  
Diel Activity ◽  
Phocoena Phocoena ◽  
Drilling Rig ◽  
The North ◽  
Production Platform ◽  
The North Sea ◽  
Exploration Drilling ◽  
Passive Acoustic

Abstract Todd, V. L. G., Pearse, W. D., Tregenza, N. C., Lepper, P. A., and Todd, I. B. 2009. Diel echolocation activity of harbour porpoises (Phocoena phocoena) around North Sea offshore gas installations. – ICES Journal of Marine Science, 66: 734–745. Echolocation clicks of harbour porpoises (Phocoena phocoena) were detected with T-PODs, autonomous, passive, acoustic-monitoring devices, deployed from an offshore-exploration-drilling-rig and gas-production-platform complex in the Dogger Bank region of the North Sea from 2005 to 2006. Echolocation-click trains were categorized into four phases of the diel cycle: morning, day, evening, and night. Porpoises were present near (<200 m) the platform, and there was a pronounced diel pattern in echolocation activity; the number of porpoise encounters (visits) was greater by night than by day. The number of click trains with a minimum inter-click interval of <10 ms also increased at night. This was confirmed by a comparison of the ratios of feeding buzzes to search-phase clicks (feeding buzz ratios) and an analysis of the changes in pulse-repetition frequencies within each train. A reasonable interpretation of this pattern was that porpoises were feeding below or around the platform at night. The evidence for changes in activity during the morning and evening was less clear, so these may be transitional phases. The pattern of porpoise-echolocation behaviour around this platform is related most probably to the diel activity of their prey. If porpoises cluster regularly around such installations within 500-m shipping exclusion zones, they may be omitted from population surveys. We conclude that offshore installations may play an important role as nocturnal porpoise-feeding stations in an overfished environment, but that further replicated and controlled studies are required. These findings should be taken into consideration during offshore-installation-decommissioning decisions in the North Sea.

scholarly journals Challenges in the Assessment of Bycatch: Postmortem Findings in Harbor Porpoises (Phocoena phocoena) Retrieved From Gillnets

2020 ◽  
pp. 030098582097245
Author(s):  
Lonneke L. IJsseldijk ◽  
Meike Scheidat ◽  
Marije L. Siemensma ◽  
Bram Couperus ◽  
Mardik F. Leopold ◽  
...  
Keyword(s):  
Health Status ◽  
North Sea ◽  
Electronic Monitoring ◽  
Nutritional Condition ◽  
Diagnostic Tools ◽  
Phocoena Phocoena ◽  
The North ◽  
Sea Bottom ◽  
The North Sea ◽  
Harbor Porpoises

Bycatch is considered one of the most significant threats affecting cetaceans worldwide. In the North Sea, bottom-set gillnets are a specific risk for harbor porpoises ( Phocoena phocoena). Methods to estimate bycatch rates include on-board observers, remote electronic monitoring, and fishermen voluntarily reporting; none of these are systematically conducted. Additionally, necropsies of stranded animals can provide insights into bycatch occurrence and health status of individuals. There are, however, uncertainties when it comes to the assessment of bycatch in stranded animals, mainly due to the lack of diagnostic tools specific for underwater entrapment. We conducted a literature review to establish criteria that aid in the assessment of bycatch in small cetaceans, and we tested which of these criteria applied to harbor porpoises retrieved from gillnets in the Netherlands ( n = 12). Twenty-five criteria were gathered from literature. Of these, “superficial incisions,” “encircling imprints,” and “recent ingestion of prey” were observed in the vast majority of our confirmed bycatch cases. Criteria like “pulmonary edema,” “pulmonary emphysema,” and “organ congestion” were also frequently observed, although considered unspecific as an indicator of bycatch. Notably, previously mentioned criteria as “favorable health status,” “absence of disease,” or “good nutritional condition” did not apply to the majority of our bycaught porpoises. This may reflect an overall reduced fitness of harbor porpoises inhabiting the southern North Sea or a higher chance of a debilitated porpoise being bycaught, and could result in an underestimation of bycatch rates when assessing stranded animals.

Cutaneous papillomavirus infection in a harbour porpoise (Phocoena phocoena) from the North Sea

1999 ◽  
Vol 144 (21) ◽  
pp. 592-593 ◽  
Author(s):  
M.-F. Van Bressem ◽  
R. A. Kastelein ◽  
P. Flamant ◽  
G. Orth
Keyword(s):  
North Sea ◽  
Harbour Porpoise ◽  
Phocoena Phocoena ◽  
The North ◽  
Papillomavirus Infection ◽  
The North Sea

scholarly journals Spatiotemporal accumulation of fatal pharyngeal entrapment of flatfish in harbour porpoises (Phocoena phocoena) in the German North Sea

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10160
Author(s):  
Stephanie Gross ◽  
Marco Roller ◽  
Holger Haslob ◽  
Miguel Grilo ◽  
Jan Lakemeyer ◽  
...  
Keyword(s):  
Baltic Sea ◽  
North Sea ◽  
Single Case ◽  
Fatal Outcome ◽  
Post Mortem ◽  
Phocoena Phocoena ◽  
Aquatic Life ◽  
The North ◽  
The North Sea ◽  
Common Sole

The evolution of a permanent separation of the upper respiratory and digestive tract is one of the adaptions cetaceans evolved for their aquatic life. Generally, it prevents odontocetes from choking on either saltwater or foreign bodies during ingestion under water. Nevertheless, several sporadic single case reports from different parts of the world show that this separation can be reversed especially by overly large items of prey. This incident can have a fatal outcome for the odontocetes. The German federal state of Schleswig-Holstein has a year-round, permanent and systematic stranding network that retrieves stranded marine mammals from its shorelines and constantly enables post-mortem examinations. In 2016, with nine affected animals, a high incidence of fatal pharyngeal entrapment of flatfish in harbour porpoises (Phocoena phocoena) occurred during spring and early summer on the German North Sea island of Sylt. All flatfish were identified as common sole (Solea solea). A retrospective post-mortem data analysis over a 30-year period from the North and Baltic Sea revealed similar yearly and seasonally case accumulations on the same island in the 1990s as well as several single case events over the whole timespan. All cases except one were caused by flatfish. When flatfish speciation was performed, only common sole was identified. From 1990 to 2019, of all examined harbour porpoises, 0.3% (2/713) from the Baltic Sea and 5.5% (45/820) from the North Sea died due to fish entrapped in the pharynx. On the North Sea coast, the occurrence of fatal obstruction shows high yearly variations from 0 to 33.3%. Years that stand out are especially 1990 to 1992, 1995, as well as 2016. The majority of all cases generally occurred between April and July, indicating also a seasonality of cases. This study evaluates the occurrence of fatal pharyngeal entrapment of fish in two geographically separated harbour porpoise populations. Additionally, common sole is clearly identified as a potentially risky item of prey for these small odontocetes.

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