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The Endangered Vaquita and the Harbour Porpoise
What is a Porpoise?
Porpoises are marine mammals in the order Cetacea. The vaquita is both the smallest porpoise and the smallest cetacean in the world. It lives in the northern part of the Gulf of California and is critically endangered. The harbour porpoise is a little bigger than the vaquita and has a much larger population and distribution. It's seen in estuaries and rivers as well as in the ocean. In general, the harbour porpoise population is doing well. One subspecies is endangered and one subpopulation is critically endangered, however.
The order Cetacea includes whales and dolphins as well as porpoises. Like their relatives, porpoises are intelligent animals that are well adapted for life in the ocean. They resemble dolphins in appearance, but their bodies are generally shorter and stockier than those of dolphins. In addition, the fin on their back has a triangular appearance in contrast to the curved or hooked fins of dolphins.
Differences Between Dolphins and Porpoises
Conical, with pointed tips
Spade-shaped, with flat tips
Front edge of the fin is curved, like a wave
Front edge of the fin is angled but is relatively straight; fin is shaped like a triangle
Often (but not always), the upper and lower jaws project beyond the head, forming a beak or rostrum
Produce sounds that are audible to humans
In general, don't produce sounds that are audible to humans
Live in large pods
Live in small pods of 2 to 5 animals
Often confident and curious around humans
Usually shy and reclusive
Relatively long lived (around forty to sixty years)
Relatively short lived (around 12 to 15 years for most porpoises, or around 16 to 17 years for the Dall's porpoise, which is the largest porpoise in the world)
We know more about dolphins than porpoises. There are only six species of porpoises while the number of dolphin species is somewhere in the thirties. In addition, porpoises tend to be reclusive animals.
A vaquita (Phocoena sinus) is a small, dark grey porpoise that reaches a maximum length of just under five feet and weighs up to 120 pounds. Most animals are smaller. The porpoise has a conspicuous black ring around each eye. It also has a black line around its lips, which gives the appearance of a smile. There is a dark line extending from the cheek to the pectoral fin or flipper on the side of the porpoise. The vaquita's body can be seen in the first video below. Unfortunately, the animals in the video are dead. There aren't many photos of living vaquitas.
The vaquita is sometimes known as the desert porpoise or the vaquita marina. It lives in a small area in the northern section of the Gulf of California, also called the Sea of Cortez. The Gulf is a narrow strip of ocean between Baja California and the Mexican mainland. The water in the Gulf is warm and the surrounding land is a desert.
Vaquitas live in turbid water and avoid human contact, so it's often hard for scientists to study them. They prefer shallow water close to the shoreline. Researchers have observed that vaquitas travel on their own or in pairs, which often consist of a mother and her calf. Occasionally they are seen in larger groups of eight to ten animals.
The fin on the top of a cetacean's body is known as the dorsal fin. The fin on each side is known as a pectoral fin or a flipper. The two fins that form the tail are known as flukes. Although the word "fin" is used in reference to cetaceans, they are mammals like us and not fish.
Diet and Reproduction
Analysis of stomach contents from dead vaquitas indicates that they feed on fish, squid and crustaceans. Like other cetaceans, vaquitas use echolocation to detect their surroundings. In this process the animal emits sound waves. The sound waves strike objects and are reflected back to the porpoise. The reflected waves provide information about the environment.
A female vaquita is thought to produce one calf every other year. Gestation is probably ten to eleven months. The female may not reproduce until she is about six years old. The vaquita is thought to have a maximum lifespan of 21 years, but in general it probably lives for a shorter time.
Vaquita Habitat: The Northern Part of The Gulf of California
A Critically Endangered Porpoise
The vaquita was discovered by scientists in 1958, based on the appearance of some skulls. An intact animal wasn't found until 1985. In 2016 - just thirty-one years after the animal was first seen by scientists - there are believed to be fewer than a hundred vaquitas still in existence.
Researchers estimate that at least forty and perhaps as many as eighty vaquitas are killed each year by becoming trapped in fishing nets, especially gillnets. Despite having an echolocation system, the vaquitas are unable to detect the nets. Although porpoises have special adaptations to help them stay underwater for a long time, they must surface to breathe and will drown if they are forcibly held underwater.
Vaquitas are believed to have a low reproductive rate, which means that when a large number of animals die the population can't be replenished quickly. The vaquita will most likely become extinct very soon unless dramatic changes are made to help the animal.
More than half of the (vaquita) population has been lost in the last three years.— World Wildlife Fund
The Baiji and the Vaquita (Dead Vaquitas Shown)
The Sad Fate of the Baiji: A Warning about the Future
The vaquita is considered to be the most endangered cetacean. The animal that until recently was the most endangered cetacean in the world - the Yangtze river dolphin or baiji - is believed to be either extinct or functionally extinct. The latter term means that there are not enough animals left for successful reproduction.
In 2006 an international research team spend six weeks performing a detailed survey of the historical range of the baiji, using a variety of equipment. They found no evidence that the animal still exists. The extinction is believed to be due to being caught as bycatch, degradation of the environment and collisions with ships.
The World Wildlife Fund says that unless changes are made now, the vaquita will likely be extinct by 2018.
Vaquita Conservation Efforts - Help Local Fisherman
Conservation organizations are very concerned about the fate of the vaquita. A refuge has been established in the area where the vaquita lives. However, a major problem is that the people in the area rely on fishing for their income. In order to save the vaquita the local people need to be helped, too.
The Mexican government is offering a compensation program to fishermen in the vaquita refuge. There are three options in this program.
- Alternative Livelihood or Buyout: The fishermen surrender their boats, fishing gear and fishing permits and receive compensation in return.
- Alternative Fishing Gear Development or Switch Out: The fishermen switch to alternate gear that doesn't trap vaquitas.
- Conservation Activities or Rent Out: The fishermen agree to eliminate all fishing in the vaquita refuge and receive compensation for this agreement.
In order for this program to be successful, the fishermen must earn as much money from the alternate livelihood or fishing method as they did from their previous livelihood. If they don't, the program is doomed to failure. In addition, the vaquita refuge has to be monitored effectively to ensure that all rules and regulations are being followed and that vaquitas are safe.
Fortunately, the compensation program has been offered for some time and has been helpful. In fact, in 2011 there was optimism that the vaquita could be saved. Unfortunately, today the vaquitas face another threat besides local fishermen.
More Conservation Efforts - Prevent an Illegal Fishery
The totoaba is a large fish that lives in the vaquita's habitat. Its maximum length is a little over six feet. International trade in this critically endangered fish is prohibited and they are becoming harder to find. Nevertheless, an illegal gillnet fishery occurs in the Gulf of California, which traps vaquitas as bycatch. "Bycatch" is an animal that is caught unintentionally while people are fishing for another creature.
Totoabas are highly valued in China for their swim bladders and earn fisherman a lot of money. A single swim bladder can sell for thousands of dollars, which makes it a very tempting catch. The swim bladder is considered to be both a delicacy and a health food. The illegal fishery for totoabas is the primary cause of the current decline in the vaquita population. Both the fish and the dolphin are in serious trouble.
The good news is that the Mexican navy is currently taken a more active role in fighting illegal fishing and the Sea Shepherd Conservation Society is removing nets that they find. The bad news is that the poachers are trying to find ways to outwit the protectors.
Barbara Taylor is a conservation biologist with NOAA (National Oceanic and Atmospheric Administration). She was involved in the hunt for the baiji in 2006. She notes that the baiji had an additional problem to fight compared to the vaquita. The baiji's former habitat is very polluted. The vaquita's is comparatively pristine. This may give the porpoise an advantage in its fight to survive. Taylor offers the following warning, however.
If we can’t save vaquitas here, where there’s only one threat, what can we save?— Barbara Taylor, NOAA
An Interview with a Head Vaquita Conservationist
The Vaquita's Future
It is extremely sad to think that a unique animal like the vaquita could become extinct in the near future. Even sadder, the animal may become extinct before we've discovered much about it. Humans caused the demise of the baiji. We may also cause the demise of the vaquita.
The vaquita has a public relations problem. It stays away from humans and lives a very private life. It doesn't swim close to boats or inspect people as some dolphins do, and it doesn't perform aerial displays. It's seen most clearly when its dead body is hauled up in fishing nets. It may be hard for some people to appreciate vaquitas without seeing living animals. In addition, the vaquita's range is so restricted and its discovery so recent that many people have never heard of the animal.
Vaquitas are beautiful creatures. There is so much to learn about them. Like their relatives, they are probably intelligent animals with fascinating lives and abilities. It may be possible to save the vaquita, but the likelihood is decreasing rapidly. Action must be taken now. Vaquitas and their plight need to be publicized and organizations that have the best chance of helping them need to be supported and encouraged.
Wild Harbour Porpoises
The Harbour Porpoise
The story of the harbour porpoise (Phocoena phocoena) is a happier one than that of the vaquita, although there is some concern about the animal's future. The porpoise lives in shallow water close to the shore. It's often found in harbours and bays, but it will sometimes venture into estuaries and up rivers. It lives in both the North Pacific and the North Atlantic Ocean.
The porpoise has a stocky appearance. It has a dark grey or blue-grey back and a paler under surface. It reaches a maximum length of six feet but is usually shorter than five feet. The animal weighs 130 pounds or less.
Although a harbour porpoise can dive to more than 650 feet, it prefers to travel close to the water surface. It surfaces frequently to breathe, producing a distinctive puffing sound that resembles a sneeze. It's sometimes referred to as a "puffing pig".
There are still unknown factors about the life of the porpoise in the wild. The animal is most often noticed in a brief appearance at the water surface. Harbour porpoises travel alone or in small groups of two to five individuals. They feed mainly on fish but eat some invertebrates too. Like many other cetaceans, they use echolocation to detect objects and food.
Saving a Harbour Porpoise Calf
Predation and Reproduction
Predators of harbour porpoises include killer whales and large sharks. The porpoises have also been killed by bottlenose dolphins in both North America and Europe. These attacks don't seem to be motivated by a desire for food. The attackers are mainly young male dolphins. They ram the unfortunate porpoises and drown them. The reason for the attacks isn't known for certain, but the leading theory is that they have something to do with the dolphins' frustrations during the breeding season.
Harbour porpoises mate in the summer. The gestation period is about eleven months and only one calf is born. The calf suckles for around eight months and is ready to reproduce at around four years of age. The animals generally live for around twelve years. Nearly all die before they reach twenty years of age.
Captive Harbour Porpoises
The harbour porpoise is better known than the vaquita and has a much wider distribution. It lives in areas close to humans. In addition, the porpoises are kept in some public aquariums, where visitors can see them up close. They are shy animals that generally stay away from boats and rarely leap out of the water, but in captivity they get used to their caregivers.
The International Union for Conservation of Nature, or IUCN, classifies the harbour porpoise species as a whole in its "Least Concern" category. Nevertheless, in some parts of its distribution the animal is experiencing problems. The Black Sea subspecies is endangered and the Baltic Sea subpopulation is critically endangered.
Some people might assume that when a species as a whole is abundant, it doesn't matter if a particular subpecies containing a small number of animals vanishes. The disappearance may be important biologically, however. Although the subspecies of a species are similar enough to breed with one another, they have genetic differences. If a subspecies becomes extinct, we lose potentially valuable genes from the species and from the Earth and we reduce biodiversity. In addition, the loss of one group of animals may sometimes be a warning sign about the fate of the species as a whole.
A Rescued Harbour Porpoise
Threats to the Population
Like the vaquita, the harbour porpoise gets caught in gillnets and other types of fishing nets as bycatch. It's unknown whether the porpoises fail to detect the nets with echolocation or whether they get trapped in the nets while they're not echolocating. Bycatch is the main problem faced by the Black Sea and Baltic Sea animals. The porpoises are also affected by the chemical pollution that collects in many of their coastal habitats. They may be influenced by noise pollution as well.
Although the harbour porpoise population as a whole seems to be doing well, we mustn't become complacent about its status. Warning signs about the future are present in the Black and Baltic Sea populations and we need to pay attention to them. It would be very sad for the harbour porpoise to become endangered. Some conservation organizations are concerned about the porpoise and are recommending procedures to protect the animal from threats. It remains to be seen whether all of these recommendations come into effect.
It's shocking and very troubling that humans have caused the extinction of an advanced animal like the baiji and that we may well cause the same result for the vaquita. I hope that the vaquita is saved and that the other species of porpoises remain safe for a long time to come.
References and Further Information
- Vaquita information from the World Wildlife Fund
- Demand for a swimbladder is endangering the vaquita from National Geographic
- Fish poachers and an endangered porpoise from The Guardian newspaper
- The Harbour Porpoise from WDC (Whale and Dolphin Conservation)
© 2012 Linda Crampton