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

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.

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

Journal of Sea Research ◽

10.1016/s1385-1101(98)00050-1 ◽

1999 ◽

Vol 41 (3) ◽

pp. 225-232 ◽

Cited By ~ 15

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

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Harbour porpoise (Phocoena phocoena) presence, abundance and distribution over the Dogger Bank, North Sea, in winter

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315416000783 ◽

2016 ◽

Vol 97 (7) ◽

pp. 1455-1465 ◽

Cited By ~ 2

Author(s):

A.-C. Cucknell ◽

O. Boisseau ◽

R. Leaper ◽

R. McLanaghan ◽

A. Moscrop

Keyword(s):

North Sea ◽

Probability Of Detection ◽

Harbour Porpoise ◽

Encounter Rate ◽

Phocoena Phocoena ◽

Survey Area ◽

The West ◽

Dogger Bank ◽

The North ◽

The North Sea

An area in the central North Sea was surveyed in November 2011 in order to estimate the abundance and density of harbour porpoises (Phocoena phocoena). A total of 2833 km of pre-determined trackline were acoustically surveyed, of which 28% included visual effort. The poor sighting conditions during the survey limited visual effort and demonstrated the advantage of using acoustic techniques for studying harbour porpoise in winter months. Absolute abundance and density estimates were calculated from acoustic encounter rates using estimates of probability of detection and mean group size. The density of harbour porpoises in the west of the survey area was almost double that in the east, with UK waters to the south-west of the Dogger Bank having the highest density of the area surveyed. The overall acoustic encounter rate was higher than most other surveys in the North Sea. The mean density across the survey area of 0.63 (95% CI 0.27–1.52) individuals km−2and distribution of porpoises was similar to that documented in the summer suggesting that high abundance of harbour porpoises in the west of the North Sea is not confined to summer months. This information is particularly relevant given plans for the construction of a large offshore wind farm on the UK section of the Dogger Bank; the resulting impacts, including acoustic disturbance from pile driving, will potentially affect substantial numbers of harbour porpoises.

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Mercury contamination of the harbour porpoise Phocoena phocoena and other cetaceans from the North Sea and the kattegat

Water Air & Soil Pollution ◽

10.1007/bf00342277 ◽

1991 ◽

Vol 56 (1) ◽

pp. 283-293 ◽

Cited By ~ 37

Author(s):

C. R. Joiris ◽

L. Holsbeek ◽

JM. Bouquegneau ◽

M. Bossicart

Keyword(s):

North Sea ◽

Harbour Porpoise ◽

Mercury Contamination ◽

Phocoena Phocoena ◽

The North ◽

The North Sea

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Population structure of harbour porpoises in the Baltic region: evidence of separation based on geometric morphometric comparisons

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315412000513 ◽

2012 ◽

Vol 92 (8) ◽

pp. 1669-1676 ◽

Cited By ~ 23

Author(s):

Anders Galatius ◽

Carl Christian Kinze ◽

Jonas Teilmann

Keyword(s):

Population Structure ◽

Baltic Sea ◽

North Sea ◽

Harbour Porpoise ◽

Baltic Region ◽

Geometric Morphometric ◽

The North ◽

The North Sea ◽

The Baltic ◽

Separate Population

The harbour porpoise is seriously depleted and threatened with extinction in the Baltic Sea. It is usually assumed that Baltic porpoises form a separate population unit, although the evidence for this has been disputed lately. Here, a 3-D geometric morphometric approach was employed to test a number of hypotheses regarding population structure of the harbour porpoise in the Baltic region. 277 porpoise skulls from Denmark, Sweden, Finland, Germany and Poland were measured with a suite of 3-D landmarks. Statistical analyses revealed highly significant shape differences between porpoises from the North Sea, Belt Sea and the inner Baltic Sea. A comparison of the directionalities of the shape vectors between these units found differences that cannot be attributed to a general, continual shape trend going from the North Sea to the inner Baltic Sea. These vectors indicate a morphological adaptation to the specific sub-areas. Such adaptation may be the result of the topographic peculiarities of the area with variable topography and shallow waters, e.g. in the Belt Sea porpoises, there may be a greater reliance on benthic and demersal prey. The present results show that isolation by distance alone is an unlikely explanation for the differences found within the Baltic region and thus support previously reported molecular indications of a separate population within the inner Baltic Sea.

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

ICES Journal of Marine Science ◽

10.1093/icesjms/fsp035 ◽

2009 ◽

Vol 66 (4) ◽

pp. 734-745 ◽

Cited By ~ 62

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.

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

Veterinary Pathology ◽

10.1177/0300985820972454 ◽

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.

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