The vaquita was defined as a species by two zoologists, Kenneth S. Norris and William N. McFarland, in 1958 after studying the morphology of skull specimens found on the beach.[5] It was not until nearly thirty years later, in 1985, that fresh specimens allowed scientists to describe their external appearance fully.[6]
The genus Phocoena comprises four species of porpoise, most of which inhabit coastal waters (the spectacled porpoise is more oceanic). The vaquita is most closely related to Burmeister's porpoise (Phocoena spinipinnis) and less so to the spectacled porpoise (Phocoena dioptrica), two species limited to the Southern Hemisphere. Their ancestors are thought to have moved north across the equator more than 2.5 million years ago during a period of cooling in the Pleistocene.[7][8][failed verification]Genome sequencing from an individual captured in 2017 indicates that the ancestral vaquitas had already gone through a major population bottleneck in the past, which may explain why the few remaining individuals are still healthy despite the very low population size.[9]
The smallest living species of cetacean, the vaquita can be easily distinguished from any other species in its range. It has a small body with an unusually tall triangular dorsal fin, a rounded head, and no distinguished beak. The coloration is mostly grey with a darker back and a white ventral field. Prominent black patches surround its lips and eyes.[11]Sexual dimorphism is apparent in body size, with mature females being longer than males and having larger heads and wider flippers.[8][failed verification][12] Females reach a maximum size of about 150cm (4.9ft), while males reach about 140cm (4.6ft).[13] Dorsal fin height is greater in males than in females.[8][failed verification][12] They are also known to weigh around 27kg (60lb) to 68kg (150lb). This makes them one of the smallest species in the porpoise family.[14]
Distribution and habitat
Vaquita habitat is restricted to a small portion of the upper Gulf of California (also called the Sea of Cortez), making this the smallest range of any cetacean species. They live in shallow, turbid waters of less than 150m (490ft) depth.[2]
Vaquitas are generally seen alone or in pairs, often with a calf, but have been observed in small groups of up to 10 individuals.[2]
Little is known about the life history of this species. Life expectancy is estimated at about 20 years and age of sexual maturity is somewhere between 3 and 6 years of age.[15] While an initial analysis of stranded vaquitas estimated a two-year calving interval,[16] recent sightings data suggest that vaquitas can reproduce annually.[17] It is thought that vaquitas have a polygynous mating system in which males compete for females. This competition is evidenced by the presence of sexual dimorphism (females are larger than males), small group sizes, and large testes (accounting for nearly 3% of body mass).[16]
Population status
Because the vaquita was only fully described in the late 1980s, historical abundance is unknown.[18] Since 1983, all confirmed specimens, records, and sightings of P. sinus were evaluated. There were 45 records of P. sinus that were collected by skeletal remains, photographs, and sightings in 1983.[19] The first comprehensive vaquita survey throughout their range took place in 1997 and estimated a population of 567 individuals.[20] By 2007 abundance was estimated to have dropped to 150.[21] Population abundance as of 2018 was estimated at less than 19 individuals.[22] Given the continued rate of bycatch and low reproductive output from a small population, it is estimated that there are fewer than 10 vaquitas alive as of February 2022.[23][failed verification][24][25] In 2023, it is still estimated that there are as few as 10 in the wild.[26]
Reproduction
Vaquitas reach sexual maturity from three to six years old. Vaquitas have synchronous reproduction, suggesting that calving span is greater than a year. Their pregnancies last from 10 to 11 months, and vaquita calves are nursed by their mothers for 6-8 months until becoming independent.[27] Vaquitas give birth about every other year to a single calf, usually between the months of February and April.[14][28] Because of their low reproduction rates, long gestation periods and larger species size, vaquitas are considered a K-selected species.[29][additional citation(s) needed]K-selected species are more vulnerable to extinction as they cannot repopulate at the rate of r-selected species.[30][failed verification] Vaquitas are on the brink of extinction because their numbers are few and they cannot replenish their population fast enough to exceed the number of vaquitas dying off.[citation needed]
Threats
Fisheries bycatch
A vaquita swims in the foreground with fishing boats in the distance
Anthropogenic effects of a rise in commercial fishing such as accidental bycatch, illegal fishing, and entanglement have been linked to the cause of their decline.[31][pageneeded] Shrimp fishing and gillnets create entanglement issues for the vaquita.[32] Aspects of illegal fishing include open access fisheries and absent fisheries management has correlated towards poaching of the main prey source of the vaquita.[33]
The drastic decline in vaquita abundance is the result of fisheries bycatch in commercial and illegal gillnets, including fisheries targeting the now-endangeredTotoaba, shrimp, and other available fish species.[4][34] Despite government regulations, including a partial gillnet ban in 2015 and establishment of a permanent gillnet exclusion zone in 2017, illegal totoaba fishing remains prevalent in vaquita habitat, and as a result the population has continued to decline.[22] Fewer than 19 vaquitas remained in the wild in 2018. Large-mesh gillnets used in illegal fishing for totoaba caused an increase in the rate of loss of vaquitas after 2011.[35]
In 2021, the Mexican government eliminated a "no tolerance" zone in the Upper Gulf of California and opened it up to fishing.[36][dubious–discuss]
In 2022 the navy began to place concrete blocks with rebar hooks into what is considered the primary area for vaquita, which was designated as a zero tolerance area (ZTA) for fishing in 2020. These are known to destroy gillnets (which can cost tens of thousands of dollars) in shallower waters. Their deployment had an immediate effect on the number of fishing boats in the area. Citing reports of echolocation outside of the ZTA, the navy expanded the area in which these blocks were placed starting in November 2023 with plans to continue placing new blocks until the end of June 2024. There are some concerns that the hooks will create ghost nets, and the navy and Sea Shepherd have removed nets trapped on hooks after being caught.[37]
Other threats
Given their proximity to the coast, vaquitas are exposed to habitat alteration and pollution from runoff. Pesticides present in the water as a result of runoff from agriculture are a threat as they can be ingested by the vaquitas, causing harm and even death. [38] Exposure to toxic compounds has also had a deleterious effect on vaquitas.[39] Bycatch, which is the incidental catch of non-target species in fishing gear, is not only the largest threat to the survival of the vaquita, but to all marine mammals around the world.[40][41][failed verification] A series of simulations in a 2022 study indicate that the species has a chance to survive and recover if all bycatch is halted, despite the presence of other threats.[42] However, the biggest threat still towards vaquita are fisheries. Northern fishing fleets have had an indirect positive impact mainly on marine mammals, because fishing on predators like sharks reduces its predatory negative impact on those groups. Although the predation of sharks towards vaquita do result in a decline in population and is seen as an alternate threat, northern fishing fleets also negatively impact this small marine mammal because the negative influence of incidental catch is greater than the positive influence of predation reduction by shark fisheries.[43]
Populations that experience a sudden decline in numbers are often more vulnerable to other threats in the future due to a bottleneck of genetic diversity within the reduced population. The reduced gene pool lowers the rate of adaptation and increases the rate of inbreeding. This phenomenon is attributed to the anthropogenic Allee effect, specifically on the end where small population size leads to low species fitness because of a lack of genetic diversity and the potential for inbreeding. Because of their small population size, vaquitas are experiencing a negative Allee effect, attributing to even smaller population growth rates, driving them further into extinction. [44] However, a 2022 study on the genetic diversity of the vaquita suggests that the marine mammal’s historically small population ensures it is unlikely to greatly suffer from inbreeding depression.[42]
Attempts to start a population in captivity have proved to be more threatening to the population than helpful. A November 2017 effort ended up traumatizing and killing one female vaquita, as well as invoking unnecessary stress onto a juvenile.[45] Still, creating a captive population could be used as a last resort to save the species and to further education on vaquitas.[46][failed verification]
Conservation
Conservation status
The vaquita is listed as critically endangered on the IUCN Red List, which is only one level above being completely extinct in the wild. It is considered the most endangered marine mammal in the world. The vaquita has been listed as critically endangered by the IUCN Red List of Threatened Species since 1996.[2] The vaquita is at risk of extinction due to its small population size.[31][pageneeded] It was approximated at one point that there were 150 individuals.[21]
The vaquita is also protected under the Endangered Species Act of 1973, the Mexican Official Standard NOM-059 (Norma Oficial Mexicana), and Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).[3]
For a small population such as the vaquita to recover after a severe decline in population size is very difficult. This conservation status is strongly influenced in part of the species reproductive biology. The large amount of unknown surrounding the key reproductive parameters of the vaquita makes understanding its potential for recovery even harder.[2]
Conservation efforts
The vaquita is found only in the upper Gulf of California, Mexico area.[48] The vaquita is at risk of extinction due to its small population size.[31][pageneeded] It was approximated at one point that there were 150 individuals left with a 10% annual decline within their population.[21] Anthropogenic effects of a rise in commercial fishing such as accidental by-catch, illegal fishing, and entanglement have been linked to the cause of their decline.[31][pageneeded] Shrimp fishing and gillnets create entanglement issues for the vaquita.[32] Aspects of illegal fishing include open access fisheries and absent fisheries management have correlated towards poaching of the main prey source of the vaquita.[33] The swim bladders of the Totoaba macdonaldi are being sold on the black market by cartels for profit.[32]
The Mexican government, international committees, scientists, and conservation groups have recommended and implemented plans to help reduce the rate of bycatch, enforce gillnet bans, and promote population recovery.[citation needed]
Protection efforts throughout Mexico have taken place in order to preserve the population. In 2017, the Government of Mexico established it as a felony to remove an endangered species.[33] Alongside this, the Government of Mexico also made a public agreement to prohibit gillnet use.[33] Efforts are proactive in incentive applications to fisheries in a system of trade-offs that benefit fishermen and the vaquita.[49][failed verification]
Mexico launched a program in 2008 called PACE-VAQUITA in an effort to enforce the gillnet ban in the Biosphere Reserve, allow fishermen to swap their gillnets for vaquita-safe fishing gear, and provide economic support to fishermen for surrendering fishing permits and pursuing alternative livelihoods.[50] Despite the progress made with legal fishermen, hundreds of poachers continued to fish in the exclusion zone. Poaching continues as the swim bladders of totoaba can sell for anywhere from $20,000 to upwards of $80,000, and they are often referred to as the "cocaine of the sea."[51] A black market for totoaba swim bladders has developed fairly recently in China (including Hong Kong). In 2017, poachers received up to US$20,000 for a kilogram of totoaba swim bladders, with some making as much as $116,000 in one day.[52]
The swim bladders of the Totoaba macdonaldi are being sold on the black market by cartel for profit.[32] With continued illegal totoaba fishing, which is largely motivated by sales to the Chinese market where it is used in traditional medicine, and uncontrolled bycatch of vaquitas, the International Committee for the Recovery of the Vaquita (CIRVA) recommended that some vaquitas be removed from the high-density fishing area and be relocated to protected sea pens. This effort, called VaquitaCPR,[53] captured two vaquitas in 2017; one was later released and the other died shortly after capture after both suffered from shock.[54]
Local and international conservation groups, including Museo de Ballena and Sea Shepherd Conservation Society, are working with the Mexican Navy to detect fishing in the Refuge Area and remove illegal gillnets.[50] In March 2020, the U.S. National Marine Fisheries Service (NMFS) announced a ban on imported Mexican shrimp and other seafood caught in vaquita habitat in the northern Gulf of California.[55]
In response to the dire circumstances facing the vaquita as by-catch of the illegal totoaba trade, in 2017 Earth League International (ELI) commenced an investigation and intelligence gathering operation called Operation Fake Gold, during which the entire illicit totoaba maw (swim bladder) international supply chain, from Mexico to China, has been mapped and researched. Thanks to the confidential data that ELI shared with the Mexican authorities, in November 2020, a series of important arrests were made in Mexico.[56]
To date, efforts have been unsuccessful in solving the complex socioeconomic and environmental issues that affect vaquita conservation and the greater Gulf of California ecosystem. Necessary action includes habitat protection, resource management, education, fisheries enforcement, alternative livelihoods for fishermen, and raising awareness of the vaquita and associated issues.[2]
Jaramillo-Legorreta, et al. stated in 2007 that captive breeding programs were not a viable option for saving the species from extinction.[57]
The Secretariat of Environment and Natural Resources (SEMARNAT) announced on February 27, 2021, that it may reduce the protected area for the vaquita in the Sea of Cortés as there are only ten of the porpoises left and it may never recuperate its historical range.[58]
Beginning in July 2022, the Mexican government placed 193 concrete blocks in the Gulf of California no-tolerance zone, intended to allow the detection of nets by acoustic sonar and prevent further entrapment of vaquitas.[59]
Creating protected areas is always an option for conservationists, but because the vaquita's range is so small, there would be no use in trying to establish habitat corridors. One option for conservationists could be trying to create buffer zones near the coast in which pesticides harmful to vaquitas are restricted or even unavailable in order to enhance the protection value of the vaquita's range.[citation needed]
In May 2023, a wildlife survey expedition discovered that the population had stabilized since it had last been recorded in 2021.[60]
Consumers
Roughly 80% of shrimp caught in the northern end of the Gulf of California, which has a high aquatic mammal bycatch rate, is consumed in the United States. As such, U.S. consumers of this shrimp are likely contributing to the vaquita extinction crisis. The Marine Mammal Protection Act of 1972, which forbids foreign fishers from exporting seafood with high levels of marine mammal bycatch, may allow for better efforts to preserve endangered vaquitas.[61]
Porpoises are small dolphin-like cetaceans classified under the family Phocoenidae. Although similar in appearance to dolphins, they are more closely related to narwhals and belugas than to the true dolphins. There are eight extant species of porpoise, all among the smallest of the toothed whales. Porpoises are distinguished from dolphins by their flattened, spade-shaped teeth distinct from the conical teeth of dolphins, and lack of a pronounced beak, although some dolphins also lack a pronounced beak. Porpoises, and other cetaceans, belong to the clade Cetartiodactyla with even-toed ungulates.
The spectacled porpoise is a small to midsize porpoise indigenous to the Southern Ocean. It is one of the most poorly studied cetaceans, partly due to its remote range in the southern ocean. What little is known about this porpoise species has been gathered mainly from stranded individuals, and a few observations of living animals made at sea.
Bycatch, in the fishing industry, is a fish or other marine species that is caught unintentionally while fishing for specific species or sizes of wildlife. Bycatch is either the wrong species, the wrong sex, or is undersized or juveniles of the target species. The term "bycatch" is also sometimes used for untargeted catch in other forms of animal harvesting or collecting. Non-marine species that are caught but regarded as generally "undesirable" are referred to as rough fish or coarse fish.
The Irrawaddy dolphin is a euryhaline species of oceanic dolphin found in scattered subpopulations near sea coasts and in estuaries and rivers in parts of the Bay of Bengal and Southeast Asia. It closely resembles the Australian snubfin dolphin, which was not described as a separate species until 2005. It has a slate blue to a slate gray color. Although found in much of the riverine and marine zones of South and Southeast Asia, the only concentrated lagoon populations are found in Chilika Lake in Odisha, India and Songkhla Lake in southern Thailand.
The harbour porpoise is one of eight extant species of porpoise. It is one of the smallest species of cetacean. As its name implies, it stays close to coastal areas or river estuaries, and as such, is the most familiar porpoise to whale watchers. This porpoise often ventures up rivers, and has been seen hundreds of kilometres from the sea. The harbour porpoise may be polytypic, with geographically distinct populations representing distinct races: P. p. phocoena in the North Atlantic and West Africa, P. p. relicta in the Black Sea and Sea of Azov, an unnamed population in the northwestern Pacific and P. p. vomerina in the northeastern Pacific.
Burmeister's porpoise is a species of porpoise endemic to the coast of South America. It was first described by Hermann Burmeister, for whom the species is named, in 1865.
Dall's porpoise is a species of porpoise endemic to the North Pacific. It is the largest of porpoises and the only member of the genus Phocoenoides. The species is named after American naturalist W. H. Dall.
Hector's dolphin is one of four dolphin species belonging to the genus Cephalorhynchus. Hector's dolphin is the only cetacean endemic to New Zealand, and comprises two subspecies: C. h. hectori, the more numerous subspecies, also referred to as South Island Hector's dolphin; and the critically endangered Māui dolphin, found off the West Coast of the North Island.
The melon-headed whale, also known less commonly as the electra dolphin, little killer whale, or many-toothed blackfish, is a toothed whale of the oceanic dolphin family (Delphinidae). The common name is derived from the head shape. Melon-headed whales are widely distributed throughout deep tropical and subtropical waters worldwide, but they are rarely encountered at sea. They are found near shore mostly around oceanic islands, such as Hawaii, French Polynesia, and the Philippines.
The northern right whale dolphin is a small, slender species of cetacean found in the cold and temperate waters of the North Pacific Ocean. Lacking a dorsal fin, and appearing superficially porpoise-like, it is one of the two species of right whale dolphin.
The pantropical spotted dolphin is a species of dolphin found in all the world's temperate and tropical oceans. The species was beginning to come under threat due to the killing of millions of individuals in tuna purse seines. In the 1980s, the rise of "dolphin-friendly" tuna capture methods saved millions of the species in the eastern Pacific Ocean and it is now one of the most abundant dolphin species in the world.
Cetacean bycatch is the accidental capture of non-target cetacean species such as dolphins, porpoises, and whales by fisheries. Bycatch can be caused by entanglement in fishing nets and lines, or direct capture by hooks or in trawl nets.
The Colorado River Delta is the region where the Colorado River flows into the Gulf of California in eastern Mexicali Municipality in the north of the state of Baja California in northwesternmost Mexico. The delta is part of a larger geologic region called the Salton Trough. Historically, the interaction of the river's flow and the ocean's tide created a dynamic environment, supporting freshwater, brackish, and saltwater species. Within the delta region, the river split into multiple braided channels and formed a complex estuary and terrestrial ecosystems. The use of water upstream and the accompanying reduction of freshwater flow has resulted in the loss of most of the wetlands of the area, as well as drastic changes to the aquatic ecosystems - an ecosystem collapse.
The totoaba or totuava is a species of marine fish, a very large member of the drum family Sciaenidae that is endemic to the Gulf of California in Mexico. It is the only species in the genus Totoaba. Formerly abundant and subject to an intensive fishery, the totoaba has become rare, and is listed by the Convention on International Trade in Endangered Species of Wild Fauna and Flora under Appendix I. It is also listed by the International Union for Conservation of Nature as vulnerable, by NatureServe as critically imperiled and under the U.S. Endangered Species Act as endangered.
Evolutionarily Distinct and Globally Endangered (EDGE) species are animal species which have a high 'EDGE score', a metric combining endangered conservation status with the genetic distinctiveness of the particular taxon. Distinctive species have few closely related species, and EDGE species are often the only surviving member of their genus or even higher taxonomic rank. The extinction of such species would therefore represent a disproportionate loss of unique evolutionary history and biodiversity.
The baiji is a possibly extinct species of freshwater dolphin native to the Yangtze river system in China. It is thought to be the first dolphin species driven to extinction due to the impact of humans. This dolphin is listed as “critically endangered: possibly extinct” by the IUCN, has not been seen in 40 years, and several surveys of the Yangtze have failed to find it. In China, the species is also called the Chinese river dolphin, Han river dolphin, Yangtze dolphin and whitefin dolphin. Nicknamed the "Goddess of the Yangtze", it was regarded as the goddess of protection by local fishermen and boatmen. It is not to be confused with the Chinese white dolphin or the finless porpoise. This is the only species in the genus Lipotes.
The Swiss Cetacean Society or Swiss Society for the Study and Protection of Cetaceans is a Swiss nonprofit organization dedicated to the conservation of marine mammals and other endangered marine species in their natural habitat. Founded in 1997, its headquarters are in Lausanne in Switzerland.
Sea of Shadows is a 2019 documentary about environmental activists, the Mexican Navy, marine scientists and undercover investigators trying to prevent the extinction of the vaquita, a species of porpoise and the smallest whale in the world, by pulling gillnets, doing research, and fighting back Mexican cartels and Chinese mafia who are destroying ocean habitats in their brutal pursuit to harvest the swim bladder of the totoaba fish, known as the "cocaine of the sea". The 1 hour and 44 minutes long film is directed by Richard Ladkani.
Dr. Amanda Bradford is a marine mammal biologist who is currently researching cetacean population dynamics for the National Marine Fisheries Service of the National Oceanic and Atmospheric Administration. Bradford is currently a Research Ecologist with the Pacific Islands Fisheries Science Center's Cetacean Research Program. Her research primarily focuses on assessing populations of cetaceans, including evaluating population size, health, and impacts of human-caused threats, such as fisheries interactions. Bradford is a cofounder and organizer of the Women in Marine Mammal Science (WIMMS) Initiative.
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NOAA (30 January 2023). "Vaquita". NOAA Fisheries Species Directory. Retrieved 19 April 2023.
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Setiawati, Ety; Rahayu, Hanum Mukti; Setiadi, Anandita Eka (2017). "Pengembangan Media Pembelajaran Modul Pada Materi Animalia Kelas X Sman 1 Pontianak". Jurnal Bioeducation (in Indonesian). 4 (1). doi:10.29406/522 (inactive 2 June 2024). ISSN2527-6522.{{cite journal}}: CS1 maint: DOI inactive as of June 2024 (link)
Torre, Jorge; Vidal, Omar; Brownell, Robert L. (October 2014). "Sexual dimorphism and developmental patterns in the external morphology of the vaquita, Phocoena sinus". Marine Mammal Science. 30 (4): 1285–1296. Bibcode:2014MMamS..30.1285T. doi:10.1111/mms.12106.
VaquitaCPR (2019). "Rescue Efforts". VaquitaCPR.org. Retrieved 14 July 2021.
Fitch, John E.; Brownell, Robert L. Jr. (13 April 2011). "Fish Otoliths in Cetacean Stomachs and Their Importance in Interpreting Feeding Habits". Journal of the Fisheries Board of Canada. 25 (12): 2561–2574. doi:10.1139/f68-227.
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