The monitoring program of cetacean populations in South Biscay, OSI-CETIS was able to implement several consecutive « Biscay » trips from mid-April to mid-May, with a « family » trip during school vacations, a training course in cetacean identification and a trip with a middle school class from Chantilly. These months of April and May have the particularity of corresponding to the calving and mating of one species, the short-finned pilot whale Dolphin
Whale Dolphins, whales, plankton... discover the wealth of our oceans by attending one of our nature courses on dolphins and whales. (Globicephala melas). Several rare observations were made and show the importance of this increased and continuous observation effort.

The contribution in knowledge of these observations shows the importance of participative sciences and the repetitiveness of the stays.

The south of the Bay of Biscay is an area rich in cetaceans. During 600 years, whalers and all of Europe knew of this resource, exploited to manufacture, among other things, oil for lighting. Since the abandonment of this hunt, most people have become unaware of the biodiversity present in this area, linked to submarine canyons, in particular the Capbreton canyon, which extends from the coast and into the west for several hundred kilometers.

If the main whale Dolphin
Whale Dolphins, whales, plankton... discover the wealth of our oceans by attending one of our nature courses on dolphins and whales. hunted in the Middle Ages is in a critical state of conservation, many other species are still present. Some of them are very little known, due to lack of studies and monitoring.

The monitoring program of cetacean populations in South Biscay, OSI-CETIS was able to implement several consecutive « Biscay » trips from mid-April to mid-May, with a « family » trip during school vacations, a training course in cetacean identification and a trip with a middle school class from Chantilly. These months of April and May have the particularity of corresponding to the calving and mating of one of the species, the short-finned pilot whale Dolphin
Whale Dolphins, whales, plankton... discover the wealth of our oceans by attending one of our nature courses on dolphins and whales. (Globicephala melas). Several rare observations were made and show the importance of this increased and continuous observation effort.

Newborns have been encountered, recognizable by the fetal folds on their bodies. These encounters are good news and are also a proof that births of this specie in this geographic area, take place in April-May, while some authors still mention births in August. The health status of this species, in the Atlantic, is undetermined, because of a lack of sufficient data.

One of these newborn pilot whales was seen in mid-May, among a group of another species. Although cases of adoption between different species are known in terrestrial and marine mammals Marine Mammals Observe marine mammals in the Iroise Sea in Brittany. Watch them develop in their natural habitat. You can do this on ourplakton discovery sailing expeditions. , they are very rare ; an analysis of the photos taken during the stays remains to be done in order to try to find traces of the « adoptive » female Bottlenose dolphin (Tursiops troncatus). Adoptions can be temporary if the mother or the group of origin is found but they can become permanent if the mother is never encountered.

It is interesting to note that several expert observers were on board that day. One saw the newborn but has no pictures. Another did not see or take a picture. A third did not see it but discovered its presence on a photograph. This shows the importance of photography as a scientific tool for monitoring marine megafauna, the importance of training and the importance of being as numerous as possible.

Another surprising encounter that animated the training session this time : a blue and white dolphin (Stenella coeruleoalba) almost entirely depigmented. This individual had been seen in August 2021. Indeed, the analysis of the dorsal fin allowed to conclude that it is the same individual which was observed in 2021 and in 2022.

The 2022 observation allowed the identification of the species with certainty, contrary to that of 2021. No case of leucism (absence of coloration but normal pigmentation of the eyes unlike albinos) has been found in the literature for this species ; a few cases are listed in other species, mainly in the northern hemisphere. This anomaly can be explained by different hypotheses documented in some species such as pollution in birds, a decrease in habitat quality in geese and food in voles. However, in cetaceans, the lack of knowledge on the origins of this phenomenon does not allow us to make any hypothesis.

Finally, in the last outing and we had a last notable observation : a young dolphin of the species Stenella coeruleoalba, seen swimming by himself. Here again, the photo taken, after the fact, allowed us to put forward a hypothesis to this unusual behavior of isolation, in appearance. We can see on it that the body of the animal presents numerous pathological necroses. In nature, a sick animal often moves away from its group. It would have been necessary to carry out an acoustic listening to try and detect the presence of the group maybe swimming several nautical miles from this isolated individual.

These rare observations underline the importance of participatory science Science La science est désormais l’affaire de tous. Découvrez la science d’une manière ludique et active. Nous vous proposons d’en découvrir plus sur nos expéditions à la voile, découverte du plancton. at sea for the census of marine mammals Marine Mammals Observe marine mammals in the Iroise Sea in Brittany. Watch them develop in their natural habitat. You can do this on ourplakton discovery sailing expeditions. in order to have as many reports as possible and thus better evaluate particular phenomena such as leucism, to better specify the lifestyles of the species and in particular the key calving periods and the relative abundance of pathology.

We are often asked "what can we do to better protect this wildlife ? One answer is to participate in the monitoring organized through the stays and develop observation and photography skills. Come and help our expertss while having fun and discovering the area during the summer and fall. Each season is special. July is the month of the beaked whales in the Basque Country, another species for which the lack of knowledge does not allow to take action on its conservation. The distribution of cetaceans around Brittany has been changing in recent years, which needs to be documented in order to understand its origin. Autumn is a very little explored season !

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