Marine mammals of France: metropolitan and overseas

Marine mammals of mainland France

Three seaboards, three communities. The English Channel and the North Sea are the only French waters where seals breed. The Bay of Biscay is the richest of the three, because it opens onto the abyssal plain and receives offshore species. The Mediterranean holds few species but sees almost all of them regularly.

Marine mammals of the French overseas territories

France has the second largest maritime domain in the world and its overseas waters hold species absent from mainland France: the dugong in Mayotte and New Caledonia, the manatee in French Guiana, the elephant seals and the fur seals of the French Southern Territories.

Saint Pierre and Miquelon, north-west Atlantic

French Antilles and French Guiana

Indian Ocean: Réunion and Mayotte

Pacific: New Caledonia, Wallis and Futuna, French Polynesia and Clipperton

Southern Ocean: Crozet, Kerguelen, Amsterdam, Saint-Paul and Adélie Land

Method: how this list is drawn up

Each area is a rectangle queried on the API of GBIF, agrégé par espèce. Une seule source pour toutes les zones, donc des chiffres comparables entre la Manche et la Polynésie. Seules les sightings observations are counted, excluding telemetry: the Bay of Biscay would otherwise show 118,892 grey seals, twice the English Channel total, of which 106,754 coming from a single tag-tracking study of a few individuals from the Molène archipelago. One Argos tag is worth twenty years of citizen sightings. The status follows from a single rule, applied to sightings later than 2000: régulier au-delà de 100 observations, occasionnel de 10 à 99, rare en dessous, historique when the species has been recorded but not since 2000. No judgement by hand: the calculation is redone.

A species known from an area from a single specimen in a collection, with no sighting at all, is excluded. This rule removes the fossil archaeocetes of Pakistan and the Miocene sirenians that French museums publish on GBIF, the eared seals of zoological parks, and the grey whale of the English Channel, whose only Atlantic traces are subfossil. The same grey whale does remain listed in the Mediterranean, where it has indeed been seen since 2000.

Names misapplied at source. Une espèce est aussi écartée d'une zone quand 99 % de ses signalements mondiaux, eaux françaises exclues, sont dans l'autre hémisphère et que la zone se tient à plus de 15 degrés de l'équateur. Un relevé français de Saint-Pierre-et-Miquelon range ainsi 202 petits rorquals sous Balaenoptera bonaerensis, the Antarctic minke whale, at 47 degrees north: without this safeguard the species came out as “regular” in the north-west Atlantic. Excluded on this basis: Balaenoptera bonaerensis Saint-Pierre-et-Miquelon (202 signalements, contre 208 au nord et 1,409 au sud dans le monde) ; Balaenoptera bonaerensis Manche et mer du Nord (2 signalements, contre 208 au nord et 1,409 au sud dans le monde) ; Eubalaena australis Saint-Pierre-et-Miquelon (1 signalements, contre 6 au nord et 17,034 au sud dans le monde).

Survey effort weighs on these figures. The number of sightings also measures survey effort. The English Channel and the North Sea are closely monitored, Wallis and Futuna almost not at all: a species appears “rare” there when it may well be common. A status is read always within a single area, never from one area to another.