As the world’s population expands and the demand for natural resources intensifies, human impact on the environment is growing at an alarming rate. We are currently experiencing the worst onslaught of species extinction since the time of the dinosaurs, and humans are to blame. The vaquita is one such species that has faced an unprecedented decline due to human activity. Vaquitas are the smallest cetacean in the world, measuring around 1.5m in length, and are found only in the Gulf of California. According to an acoustic survey last year, only about 30 individuals remain. These shocking numbers have prompted a team of scientists to develop a controversial plan to save this species by capturing some remaining animals for a captive breeding program.
The major reason for the decline of the vaquita population is thought to be their vulnerability to capture in gillnets which are deployed by fishermen in the gulf to capture the endangered totoaba fish. Bans on this type of fishing has proved to be ineffective. Although Mexico declared an emergency gillnet ban in 2015, these nets are still used illegally to capture totoaba to be sold on the black market. The swim bladders are used in traditional Chinese medicine to treat a wide range of ailments from liver disease to arthritis. A single swim bladder can fetch up to $100,000, making it a desirable target for fishermen that depend on the ocean for their livelihood. The totoaba fishery is now run by criminal activity and has gone underground, making it extremely difficult to regulate.
In order to futher understand the impacts of the gillnet fishery, scientists undertook an acoustic survey to estimate the number of vaquitas that remain. Vaquitas use echolocation to find their prey, which can be heard by underwater devices as a series of clicks. Researchers deployed acoustic monitoring devices to record vaquita echolocation in order to estimate their population size. The results were grim; the number of recorded clicks per day dropped by 44% from 2015 to 2016, indicating at 49% decline in the population in just one year! The research suggests that without human intervention, vaquitas will likely be extinct within a few years.
In order to save this species from extinction, a team of scientists have developed a controversial plan to capture an unspecified number of vaquitas in October for a breeding program. Vaquitas are a shy species that tend to avoid boats and are rarely seen, making their capture challenging, so researchers have developed a unique method to find vaquitas in the dark waters of the gulf. The vaquita recovery team plans to use bottlenose dolphins from the US Navy Marine Mammal Program. Bottlenose dolphins already inhabit the Gulf, and therefore vaquitas are used to their presence and will not frighten the porpoises. Naval trainers will teach the dolphins to seek out “air-filled lungs” using their sonar. When a vaquita is detected, the dolphin will alert its trainer by touching a target on the side of the vessel, and then swim in the direction of the vaquita. Trial runs involving harbour porpoises in San Francisco Bay have already been successful.
Researchers are not sure how the vaquitas will react to being captured, and there is concern about how they will respond. Capture attempts with harbour porpoises have been challenging in the past, as they often stopped breathing. Scientists are expecting a similar response with vaquitas, and are using their experience with harbour porpoises to prepare for such events. When porpoises dive, water pressure on their breast bone prompts their brains to hold their breath so that they do not drown. When removed from the water and placed on a hard surface, the pressure on the harbour porpoise’s breast bone triggers this automated response, and the animal suffocates. Previous research has shown that putting porpoises on soft material lessens the pressure and the animal begins to breathe normally again. The capture of wild animals has always been a heated topic, and some backlash from the public is likely to occur. The team feels that without immediate human intervention, there is no other way to stop their extinction. Although often fraught with controversy, captive breeding plans have been successful for the recovery and re-introduction of other endangered species, such as the red wolf, the California condor, and the African penguin have been successful. Researchers hope that this program will save the vaquita from vanishing from our oceans, and prevent one more nail in the coffin of our planet’s marine biodiversity.