ASCOBANS is an acronym for “Agreement on the Conservation of Small Cetaceans of the Baltic and North Seas”. ASCOBANS was concluded in 1991 as the Agreement on the Conservation of Small Cetaceans of the Baltic and North Seas (ASCOBANS) under the auspices of the Convention on Migratory Species (CMS or Bonn Convention) and entered into…


CIRVA is an acronym for Comité Internacional para la Recuperación de la Vaquita (International Committee for the Recovery of the Vaquita). CIRVA is an international team of scientists established by the government of Mexico. CIRVA was tasked with the development of a recovery plan for the vaquita based on the best scientific evidence available.

How does ocean pollution affect porpoises?

Many contaminants are lipophilic, meaning that they dissolve in fats (lipids). Porpoises have blubber, a thick layer of fat underneath the skin that keeps them warm. And that is where contaminants accumulate over time and get stored. Porpoises have a very high metabolic rate, meaning that they need to eat constantly. They can be described…

How many Vaquitas are left in the world in 2020?

The latest report by the International Committee for the Recovery of the Vaquita (CIRVA) estimates that only between 6 and 22 individuals remained alive in 2018. It is possible, though, that there no more than 10 vaquitas left. (For comparison, in 1997, the population was estimated to be about 600 individuals strong.) During recent surveys,…

If there are only so few left, can we still save the vaquita?

We can’t know for sure. But there have been several examples of marine mammal species that have come back from the brink of extinction. The vaquita population can recover if the immediate threat is removed from its habitat. And the only real danger for the vaquita are gill-nets.


The totoaba (Totoaba macdonaldi) is a very large species of fish that is endemic to the Gulf of California in Mexico. Once abundant, the totoaba has become rare and is listed on IUCN Red List as “critically endangered”. Fishing for totoaba was banned in Mexico in 1975, but due to its high value on the…

What efforts have been made to save the vaquita?

Since the vaquita was first described by science and shortly after declared “vulnerable” by the IUCN, numerous actions have been taken by the Mexican government to save the species. However, none of these actions have prevented the decline of the population.
A ban on gill-nets should have halted the decline, but gill-net fishing continues, with seasonal permits for a local species of fish, the corvina, and illegally for the totoaba.

Why are Dall’s porpoise hunted in Japan?

In Japan, thousands of Dall’s porpoise are killed in directed hunts every year. The animals are killed for consumption. As there are no recent abundance estimates for Dall’s porpoise in Japanese waters, it is unknown whether the take is sustainable, i.e. whether it is having any negative effects on population trends. In addition to directed…

Why are Mexico’s efforts to save the vaquita not effective?

Mexico has tried various things to help the vaquita population recover: it declared a refuge, later stepped up its efforts and banned gill-nets throughout the vaquita’s range, sending its navy and collaborating with NGOs for enforcement. But illegal fishing continues to this day. Totoaba are frequently found discarded in large numbers (only their swim bladders…

Why is the vaquita endangered?

The single most serious thread to the vaquita, and the cause for its rapid decline, is the use of gill-nets in the vaquita habitat.

A gill-net is a wall of netting that hangs in the water column. The mesh is designed so that fish can get their heads through, but not the rest of their bodies. As they struggle to free themselves, they get entangled with their gills. Gill-nets are very effective and used around the world, but often lead to large amounts of by-catch and pose a threat to other marine animals, such as sea turtles, seals and sea lions and cetaceans like the vaquita. If a vaquita gets entangled, it only has minutes to free itself. Most animals drown, and those that escape often do so with severe injuries.