Boat campaigns

During boat campaigns, many techniques and methods are available to study cetaceans in their natural environment, and most of them are complementary. Here are some examples:

– Visual observation: two observers, placed on each side of the vessel, scan the surface of the sea for cetacean sightings (blow, fin, jump, etc.). For each detection, a number of data are collected, including: the species, the number of individuals, the behavior... The track coordinates and the weather conditions are also recorded. This method allows to study and monitor the diversity of species occuring in the studied area, their distribution, and their habitat use. If the boat track covers the study area in a regular manner, and if the quantity of data is sufficient, it is then possible to determine the density and abundance of the main identified group of species. This technique also allows to collect data on other pelagic megafauna species (tuna, sharks...) but also on the human activities occuring in the studied area in order to assess their impact on cetaceans.

– Acoustic recordings: in addition to visual observation, it is possible to detect cetaceans with the sounds they produce using a hydrophone, either towed at the back of the boat, or periodically immersed when the vessel is stationary. This technique is complementary to visual observations: it facilitates the detection of species that are difficult to observe at the surface, such as deep divers, but it is not yet as accurate as observations, especially in terms of species identification and counting. For more information on acoustics, see the dedicated page.


– Photo-identification: this technique consists in photographing certain parts of the body of the observed animals to identify them individually (e.g.: dorsal fin for dolphins or caudal fin for humpback whales). In the long term, generally after several years of data collection, photoidentification allows to determine and follow some population demographic parameters, such as abundance, reproduction, growth, mortality, and even to work on individual social relationships within groups. This technique is mainly used to study and monitor small coastal populations of marine mammals.

– Tagging: this technique consists on fixing an electronic device on an individual that will collect data on the animal’s location, its behavior and certain characteristics of its environment. Some tags remain attached a few hours only. They allow to obtain very detailed information on communication, 3 dimensions underwater movements, etc. Other tags remain attached for up to several months and transmit their data by satellite. They allow to follow the movements of individuals over long distances, but also to obtain information on diving duration, water temperature and salinity, etc. This is a very useful technique to study the migratory movements of whales.


– Biological sampling: sample collection can be indirect (collection of skins or excrements floating on the surface) or direct (piece of skin and blubber). Direct sampling (biopsy) is done with an arrow equipped with a small hollow cylinder fired with a crossbow or an air gun. Depending on the nature of the samples, we can learn more about the genetics, the diet, the level of contamination to different pollutants or the stress level of the animals.


The SPAW RAC has contributed to several campaigns at sea in recent years, for example:
– Megara campaigns organized around the islands of St. Martin and St. Barthélemy, which aim to increase knowledge about humpback whales in the Caribbean. See for example the 2014 mission.
– The CARI’MAM campaigns, which aim to strengthen knowledge on cetacean populations in the Caribbean and to set up their monitoring.