Totoaba

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Totoaba
Systematics
Spinefish (Acanthopterygii)
Perch relatives (Percomorphaceae)
incertae sedis
Family : Umberfish (Sciaenidae)
Genre : Totoaba
Type : Totoaba
Scientific name of the  genus
Totoaba
Villamar, 1980
Scientific name of the  species
Totoaba macdonaldi
( Gilbert , 1890)

The name Totoaba ( Totoaba macdonaldi ) or Totuava is the name of a umber fish and comes from an Indian language (from residents of the Sonoran Desert ). It (allegedly) actually means “insatiable bird” because it was believed that hibernating Canadian brent geese ( Branta bernicla nigricans ) transformed into these fish in the waters of the Gulf of California .

Due to its ecology, the impairment of its habitat by humans and the ongoing illegal hunting, the species is facing extinction .

features

The totoaba is the largest umberfish in the western hemisphere: it can reach over two meters in length and weigh over 100 kg (females - the drumming males remain significantly smaller. If, however, the reports of previous catches weighing 330 pounds could be proven - for example by means of sub-recent ear stones - the totoaba could even have exceeded the size of the eagle fish ). They can reach the age of 15.

In body shape, Totoaba resembles a sea ​​bass ( Dicentrarchus ), but the caudal fin is large, fan-shaped (actually pentagonal, but the rear corner is at an almost straight angle). The color is the light shadow fish silver with a more or less brown tinge; the fins are dark. Young fish have a spotted back.

Rays : dorsal 1 X-XII, dorsal 2 I / ~ 25, anal II (weak) / 7–9, pectoral 15–17. Lateral line scales: about 60 (i.e. the fish has 29 vertebrae - the maximum in Sciaenids).

The almost upper mouth is not very large. The dentition on the edge of the jaw is quite weak, at least there are larger fang (but not dog) teeth on the outside (front) on the premaxillary and inside on the dental. (The pikeperch , for example, has dog teeth : they are used to pierce the prey, which usually dies immediately from stress.) The pharyngeal teeth are squeezed enough that Totoaba can also eat benthic and nectic (free-swimming) crustaceans , but is preferred of this hunting in schools predator sardines ( Sardinops ), anchovies ( Anchoa : esp. ischana ) and king mackerel ( Scomberomorus concolor ) of the free water and (benthic) and flatfish , smaller Umbern ua- to ethology of drumming is (like most croakers ) no investigation.

Occurrence

This drummer lives only in the northern part of the Gulf of California (also called Lake Cortés ). The Cortés Sea, which is comparable in size to the Adriatic Sea , is inhabited by a number of endemics - including even a small dolphin species ( Tursiops sinus ). The distribution area extends to about Tortuga Island (27 ° 50'N). Farther south one finds at most scattered specimens; Totoaba never leaves the Gulf . The estuary of the Colorado River to the north serves as a spawning and development area for young fish. The Totoaba schools used to move from late autumn to spring time and again to spawn in the large, cracked estuary of this river. For the young fish, about 2% salinity is optimal. For decades, however, spawning migration has only taken place once - in February (if at all). Smaller rivers that flow into the northern Gulf can also form small brackish zones during the rainy season, which are suitable for spawning. The fish becomes sexually mature at the age of 6 (males) or 7 (females), with a length of approx. 60–75 cm.

evolution

Gilbert described the species as belonging to Cynoscion because of outward, convergence- based features of free-water hunters. Today one thinks more of being able to make references to Bahaba (e.g. in otolith building); but since Bahaba is a genus of Southeast Asia and one generally has no clear ideas about the cladistics within the Sciaenidae , this also seems implausible if one thinks of transpacific affinities (a "transatlantic" from the times of the Tethys , the drifting of North America and a The then still existing strait to the East Pacific is of course conceivable).

In many fish families it can be observed that adaptive radiation also produces a predator, which then often feeds on the related fish species (cf. for example Belonesox among the Poeciliidae ). It is assumed that Totoaba itself evolved into a top predator in the Gulf of California - perhaps from “corvina” -like ancestors (cf. Meerrabe or White Umber ); Similar assumptions can be made for the eagle fish in the Mediterranean. There are fossil otoliths from the Lower Miocene from marine sand layers from Bakersfield (Ca.) , which are assigned to a Totoaba fitchi . Extant is totoaba monotypic .

Human interventions

The Totoaba has always been hunted by the Indians of Lower California and the Sonora and mostly speared from boats. The “cheek” muscles (ie the adductor mandibulae ) were considered particularly tasty - as with many other fish, in other cultures too. A hundred years ago, according to hearsay, there were huge swarms - the true population size at that time is the subject of discussion. After the arrival of the whites in the area, it took some time before they too became aware of the fish. However, Chinese working in the area were the first to start fishing totoabas for commercial purposes, for the sake of the swim bladder. Certain soup preparations in their homeland require the gelatinous protein ichthyocolla ( isinglass , a collagen ), which is obtained particularly from sturgeon , but is also known from many other types of fish. Similar collagens are found in the salangan nests, which are used for swallow's nest soup . So from around 1915 onwards, increasing amounts of totoabas were killed, but only the swim bladder ("buche") was removed . The swim bladders of the females proved to be easier to obtain, those of the males with their appendages torn too easily. The fish themselves rot on the bank or in the water, travelers reported the unbearable stench in the area. The swim bladders could easily be dried and shipped to China at a profit.

There, the fish's swim bladder is “worth more than its weight in gold to this day . In China, the bubbles are considered a remedy, status symbol and investment. For cartels on both sides of the Pacific, the illegal swim bladder trade means higher profits - and much lower risks than drug trafficking ”. In Chinese cuisine, the totoaba is considered an aphrodisiac and rejuvenating agent; Here, too, the collagen in the swim bladder is required for certain soup preparations. In smuggling, fishermen are paid between 500 and 3,000 US dollars per kilogram; in China and Hong Kong then up to 80,000 US dollars, more than the corresponding amount of cocaine .

It was only later, after World War II , that the value of the totoaba as a food fish was recognized - this only became possible when enough ice was available for refrigerated transport by truck to larger cities in the USA (from around 1924). When catching the fish ( longlines , nets), Indians (e.g. the Seri ) were also involved, who received less profit than whites, but were now also allowed to work with dynamite . A decrease in catches began to be noticed after the amount of water that the Colorado River sent into the Cortés Sea had decreased drastically (by more than 95%) due to the large irrigation systems, drinking water withdrawals, among other things, in the upper reaches in the 1930s . whereby the salinity in the estuary increased, which again had an adverse effect on the emergence of the juvenile fish. Even soiling z. B. with artificial fertilizers , later with pesticides , began to have an effect.

In 1943 over 2,000 tonnes could still be caught, in 1975 only 58. Only then was the fish finally placed under complete protection. Since then, fishing has been banned; but since the environmental changes cannot be reversed, the Totoaba is now practically exterminated : For example, until recently hundreds of thousands of young fish were killed every year as “ shrimp ” bycatch . This is where the mistake comes in that the hundred thousand eggs or more that can be seen when filleting the fish meat in the ovaries of mature females could, if “necessary”, quickly replace the overexploitation of the population.

In the rest of the population, poaching is still mainly carried out by US-Americans (" Mafia ") and the fish is exported, declared as " White Sea Bass " (ie Atractoscion ). If the population were “intact”, such a large fish could of course be the “dream destination” of many sport fishermen, who in this way could significantly contribute to the standard of living in the agriculturally barely usable area of ​​the Gulf of California. For a long time, however, short-term profit was more important to fisheries than medium-term, forward-looking resource planning (" sustainability "). The situation is exacerbated by a secular decline in precipitation in the region. Therefore, the Totoaba breeding measures that have now been introduced (even with our own desalination plants ) have not yet brought any significant improvement in the situation.

literature

  • 1995, LN Chao: Sciaenidae. Corvinas, barbiches, bombaches, corvinatas, corvinetas, corvinillas, lambes, pescadillas, roncachos, verrugatos. In: W. Fischer, F. Krupp, W. Schneider, C. Sommer, KE Carpenter and V. Niem (eds.): Guia FAO para identificacion de especies para los fines de la pesca Pacifico Centro-oriental. 3 volumes, pp. 1427-1518

Web links

Individual evidence

  1. ↑ Carmen Peña, Ivonne Marschall: "I am not an aphrodisiac" . In: Neues Deutschland , March 2, 2018
  2. ^ A b c Badische Zeitung: The greed sacrificed - Panorama - Badische Zeitung. Accessed December 30, 2019 .
  3. ^ A. Villamar: Totoaba, un nuevo género de la familia Sciaenidae del Golfo de California, México (Pisces: Teleostei). Anales de la escuela nacional de ciencias biológicas, México, 23, pp. 129-133, 1980
  4. ^ CA Rodriguez et al .: Macrofaunal and isotopic estimates of the former extent of the Colorado River estuary, upper Gulf of California, México. J. arid environments, 49, pp. 183-193, 2001
  5. ^ Richard W. Huddleston and Gary T. Takeuchi: First fossil record of Totoaba Villamar 1980 (Teleostei, Sciaenidae) based upon early Miocene otoliths from California with comments on the ontogeny of the saccular otolith. Bull. South. Calif. Acad. Sci., 106, pp. 1-15, 2007
  6. ^ A b Conrad J. Bahre, Luis Bourillon and Jorge Torre: The Seri and commercial totoaba fishing (1930–1965). Journal of the Southwest, 42, 2000
  7. ^ The cocaine of the seas - On the hunt for the "beeches" , SPIEGEL Online 2019/2
  8. ↑ Diego Lercardi and Ernesto A. Chavez: Possible causes related to historic stock depletion of the totoaba, Totoaba macdonaldi (Perciformes: Sciaenidae), endemic to the Gulf of California. Fisheries research, 86 (2-3), pp. 136-142, 2007
  9. ^ Robert Kunzig: Drying of the west. Natl. Geogr. Mag., 90-113, Feb. 2008