The team emphasized that the study was not a full population estimate, which they will present in January after further research.
In the last full population estimate, carried out in 2017, CIRVA found there were only 30 vaquitas left.
Known as “the panda of the sea” for the distinctive black circles around its eyes, the vaquita has been decimated by gillnets used to fish for another species, the also endangered totoaba fish.
The totoaba’s swim bladder is considered a delicacy in China and can fetch up to $20,000 on the black market.
Hollywood star Leonardo DiCaprio and Mexican billionaire Carlos Slim have thrown their backing behind the campaign to save the vaquita.
Last year the Mexican government launched a bold plan to round up remaining vaquitas with the help of trained dolphins and relocate them to a protected enclosure.
However, it had to be aborted when one of the first captured vaquitas died.