The sea mammal lies between two locks between Paris and the port of Le Havre where the Seine flows.
French authorities issued a warning and asked “the entire population not to attempt to approach or interact with the animals”.
“Even a very careful approach is difficult because the animal makes a lot of changes in direction,” said Gerard Mager, deputy head of the Cotentin’s Cetacean Research Group (GEEC).
The beluga today “had the same behavior as yesterday [quinta-feira]Very elusive, makes a very short impression on the surface, followed by a long breath”, added the manager.
The Seine, which is “highly polluted” and “very noisy” due to heavy shipping, is “not very welcoming” to noise-sensitive cetaceans, according to the Sea Shepherd Society.
Earlier in the day, the state of health of the beluga, which reaches four meters in length as an adult, was deemed “worrisome” by the department of Ure in northwestern France, which saw the animal.
In May, an orca got into trouble in the sea. Attempts to save it failed and the animal starved to death. The postmortem confirmed the “poor physical condition” of the orca, an “immature” female measuring four meters and weighing 1,100kg, with a bullet lodged in the base of the mammal’s skull.
The sad result “is because we want to avoid the beluga. For us, it is necessary to do a quick DNA test to identify its origin and relocate it,” Sea Shepherd head Lamya Essemlali told AFP.
According to the Belakis Observatory, which specializes in marine mammals, this is the second beluga to be found in France, after a fisherman accidentally caught one in his net in 1948 on the Loire coast (centre).