TY - JOUR

T1 - Harbour porpoises (Phocoena phocoena) in north-western France

T2 - Aerial survey, opportunistic sightings and strandings monitoring

AU - Jung, J. L.

AU - Stéphan, E.

AU - Louis, M.

AU - Alfonsi, E.

AU - Liret, C.

AU - Carpentier, F. G.

AU - Hassani, S.

PY - 2009/8/1

Y1 - 2009/8/1

N2 - 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 1578km aerial survey of the Brittany coasts concerned harbour porpoises, with an encounter rate of 1.5 individuals per 100km that peaked to 5.8 per 100km 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.

AB - 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 1578km aerial survey of the Brittany coasts concerned harbour porpoises, with an encounter rate of 1.5 individuals per 100km that peaked to 5.8 per 100km 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.

KW - Aerial survey

KW - Brittany coasts

KW - Harbour porpoise

KW - North-western France

KW - Opportunistic sightings

KW - Phocoena phocoena

KW - Stranding monitoring

UR - http://www.scopus.com/inward/record.url?scp=69749128694&partnerID=8YFLogxK

U2 - 10.1017/S0025315409000307

DO - 10.1017/S0025315409000307

M3 - Journal article

AN - SCOPUS:69749128694

VL - 89

SP - 1045

EP - 1050

JO - Journal of the Marine Biological Association of the United Kingdom

JF - Journal of the Marine Biological Association of the United Kingdom

SN - 0025-3154

IS - 5

ER -