Totoaba

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Totoaba
Tanques de totoaba en la Universidad Autónoma de Baja California.jpg
Tank with totoaba at the Autonomous University of Baja California, Mexico
CITES Appendix I (CITES)[2]
Scientific classification edit
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Perciformes
Family: Sciaenidae
Genus: Totoaba
Species:
T. macdonaldi
Binomial name
Totoaba macdonaldi
(Gilbert, 1890)
Synonyms

Cynoscion macdonaldi Gilbert, 1890

The totoaba or totuava (Totoaba macdonaldi) 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.[3] 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 on CITES Appendix I,[2] as critically endangered on the IUCN Red List,[1] and as 'endangered' under the Endangered Species Act.[3]

Life cycle[edit]

The totoaba can grow up to 2 m (6.6 ft) in length and 100 kg (220 lb) in weight,[2] making it the largest species in the drum family,[3] together with the similar-sized Chinese bahaba (Bahaba taipingensis).[4] The totoabas’ diet consists of finned fish and crustaceans. Individuals may live up to 15 years, but sexual maturity is usually not reached until the fish are 6–7 years old. As totoabas spawn only once a year, population growth is slow, with a minimum population doubling time of 4.5 to 15 years.[2] The totoaba spawn in the Colorado River Delta, which also serves as a nursery for the young fish.[1]

The totoaba population is found in two distinct groups. Larval and juvenile stages occupy the Colorado delta, while the adult breeding population lives for most of the year in deeper water towards the middle of the Gulf of California. The adult population migrates to the Colorado delta in April and May to spawn. One-year-old totoabas are metabolically most efficient in brackish water of about 20 parts per thousand (ppt) salinity, a level that occurred naturally in the delta before the diversion of water from the river that occurred in the middle of the 20th century.[5]

Spearfishing[edit]

Back before the fishing ban on the totuaba in 1975, a spearfishing world record for the species was set by spearfisherman Hal Lewis. The fish was caught on November 20, 1962, and tipped the scales at 33.8 kg (74.5 lb). The record still stands today due to the closing of the fishery.[6]

Threats[edit]

The diversion of water from the Colorado River within the United States leaves little or no fresh water to reach the delta, greatly altering the environment in the delta, and the salinity of the upper Sea of Cortez. The flow of fresh water to the mouth of the Colorado since the completion of the Hoover and Glen Canyon dams has been only about 4% of the average flow during the period from 1910 to 1920. This is considered to be a major cause of the depletion of the totoaba population.[5][7][8][9] With the loss of the freshwater flow from the river, salinity in the delta is usually 35 ppt or higher.[5]

Poaching[edit]

Another threat to the totoaba is from human poaching: the swim bladder is a valuable commodity, as it is considered a delicacy in Chinese cuisine; the meat is also sought-after for making soups. It can fetch high prices – 200 bladders may be sold for $3.6 million at 2013 prices – as it is erroneously believed by many Chinese to be a treatment for fertility, circulatory, and skin problems.[10][11] The swim bladders are often smuggled to Hong Kong where illegal but import screenings are lax and from there sometimes forwarded to the Chinese mainland where import screenings are stricter.[12] This trade once focused on the Chinese bahaba, but as its population became depleted, the trade shifted to the related totoaba.[13][14] The illegal totoaba fishery also threatens the vaquita, a critically endangered porpoise endemic to the northern Gulf of California that appears to be doomed to extinction unless the setting of gillnets in its habitat can be halted.[15]

Conservation[edit]

It has been illegal to catch toatoba since 1975 when it was placed on the Mexican Endangered Species List.[1] In 1976 it was added to CITES Appendix I and in 1979 it was placed on the US Endangered Species List.[1]

On 16 April 2015, Enrique Peña Nieto, the President of Mexico, announced a program of rescue and conservation of the vaquita and the totoaba, including closures and financial support to fishermen in the area.[16] This closure is necessary as they were still caught as a bycatch in the legal fishery for other species.[1] Some commentators believe the measures fall short of what is needed to save the vaquita.[17]

The Chinese trade in totoaba swim bladders has been a primary reason for its decline. Despite being illegal, this trade often happened quite openly and traders reported being warned before checks by Chinese authorities, allowing them to hide the swim bladders.[18] More recently, both Mexican and Chinese authorities have tightened checks and performed raids, resulting in large confiscations and several arrests.[19][20][21]

The toatoba is suitable for fish farming due to the relative ease of breeding it in captivity and its high growth rate.[13][22] Although this mainly is done to supply the food market,[22] tens of thousands of totoaba hatched in captivity have been released into the wild in an attempt of saving the species.[23]

Commercial trade[edit]

Commercial fishing for totoaba began in the 1920s. The catch reached 2,000 metric tons in 1943, but had fallen to only 50 tons in 1975, when Mexico protected the totoaba and banned the fishery. Anecdotal evidence suggests that totoabas were very abundant prior to the start of the commercial fishery, but no hard evidence now indicates natural population size. Recent studies indicate that the totoaba population has stabilized at a low level, perhaps a bit larger than when the commercial fishery was banned in 1975. Totoabas are still caught as bycatch in fishing for other finned fish and for shrimp, and in illegal fishing for totoaba directly. Some totoabas are illegally exported to the United States, often misidentified as white seabass.[5][7][8]

The government of Baja California has authorized commercial raising of totoaba in fish farms.[24][25] Although now done at a relatively large scale by private fish farms,[23] much of the initial research in the captive keeping, breeding and raising of totoaba was done at the Autonomous University of Baja California.[22]

References[edit]

  1. ^ a b c d e f Findley, L. (2010). "Totoaba macdonaldi". The IUCN Red List of Threatened Species. IUCN. 2010: e.T22003A9346099. doi:10.2305/IUCN.UK.2010-3.RLTS.T22003A9346099.en. Retrieved 6 January 2018.
  2. ^ a b c d Froese, Rainer and Pauly, Daniel, eds. (2019). "Totoaba macdonaldi" in FishBase. May 2019 version.
  3. ^ a b c "Totoaba (Totoaba macdonaldi)". NOAA Office of Protected Resources web site. NOAA. 2012-12-05. Archived from the original on 2016-01-29. Retrieved 2014-08-19.CS1 maint: BOT: original-url status unknown (link)
  4. ^ Froese, Rainer and Pauly, Daniel, eds. (2019). "Bahaba taipingensis" in FishBase. May 2019 version.
  5. ^ a b c d Review of CITES Appendixes Based on Resolution Conf. 9.24 (Rev.) Totoaba macdonaldi (Mexican seabass) Archived 2007-09-27 at the Wayback Machine - Retrieved July 11, 2007
  6. ^ International Underwater Spearfishing Association: World Record, Totuava, Totoaba macdonaldi. Retrieved 18 May 2019.
  7. ^ a b Sonoran Desert Coastal Conservation - Totoaba - Retrieved July 11, 2007
  8. ^ a b Monterey Bay Aquarium Seafood Watch - Totoaba Archived 2007-08-11 at the Wayback Machine - Retrieved July 11, 2007
  9. ^ Earstones Tell Fishes' Tale in Colorado River Estuary - Retrieved June 10, 2008
  10. ^ Morell, V. (2017-02-01). "World's most endangered marine mammal down to 30 individuals". Science. doi:10.1126/science.aal0692.
  11. ^ Stickney, R. (25 April 2013) "Multi-Million Dollar Fish Bladder Factory Uncovered in Calexico". NBC San Diego.
  12. ^ Guilford, G. (25 August 2015). How China’s fish bladder investment craze is wiping out species on the other side of the planet. Quartz. Retrieved 18 May 2019.
  13. ^ a b Juarez, Lorenzo M.; Pablo A. Konietzko; and Michael H. Schwarz (15 December 2016). Totoaba Aquaculture and Conservation: Hope for an Endangered Fish from Mexico’s Sea of Cortez. WAS. Retrieved 18 May 2019.
  14. ^ Hance, J. (11 January 2016). China's craze for 'aquatic cocaine' is pushing two species into oblivion. The Guardian. Retrieved 18 May 2019.
  15. ^ Joyce, C. (2016-02-09). "Chinese Taste For Fish Bladder Threatens Rare Porpoise In Mexico". National Public Radio. Retrieved 2017-02-06.
  16. ^ "U.S. supports Mexico's efforts to save the vaquita". El Universal. 16 April 2015.
  17. ^ Smith, Zak (16 March 2015). "This Week in Whales Focus: The Call to Ban Mexican Seafood Products Gets Louder After Mexico Announces its Plan for Vaquita Extinction". nrdc.org.
  18. ^ Carrington, D. (16 May 2017). Chinese appetite for totoaba fish bladder kills off rare porpoise. The Guardian. Retrieved 18 May 2019.
  19. ^ Cannon, J.C. (1 May 2018). More than 800 totoaba swim bladders confiscated by Mexican authorities in smuggling busts. Mongobay. Retrieved 18 May 2019.
  20. ^ Dasgupta, S. (29 December 2018). China seizes totoaba swim bladders worth $26 million, arrests 16. Mongobay. Retrieved 18 May 2019.
  21. ^ BBC (7 March 2019). China accuses 11 of smuggling totoaba swim fish bladder. Retrieved 18 May 2019.
  22. ^ a b c Dodd, Q. (27 November 2017). Saving the totoaba for fun and profit. HatcheryInternational. Retrieved 18 May 2019.
  23. ^ a b Kiy, R. (5 July 2018). Fourth Release of Totoaba in Baja California Sur: A Unique Alliance Between Government and the Private Sector to Protect a Species at Risk of Extinction. Business Wire. Retrieved 18 May 2019.
  24. ^ Penuelas Alarid, Bernardo (31 October 2010). "Comercializarán totoaba criada en cautiverio". El Mexicano (in Spanish). Retrieved 4 September 2011.
  25. ^ Santos Malagón, Sac-Nicté (6 September 2010). "Buscan hacer de la totoaba un producto distintivo". La Voz de la Frontera (in Spanish). Retrieved 4 September 2011.

External links[edit]