Chapalichthys encaustus

Chapalichthys encaustus
Chapalichthys encaustus
Chapalichthys encaustus
Chapalichthys encaustus
Chapalichthys encaustus
Chapalichthys encaustus
Chapalichthys encaustus
Chapalichthys encaustus
Chapalichthys encaustus
Chapalichthys encaustus
Chapalichthys encaustus
Chapalichthys encaustus
Chapalichthys encaustus
Chapalichthys encaustus
Chapalichthys encaustus
Chapalichthys encaustus
Chapalichthys encaustus
Chapalichthys encaustus
Chapalichthys encaustus
Chapalichthys encaustus
Chapalichthys encaustus
Chapalichthys encaustus
Chapalichthys encaustus
Chapalichthys encaustus
English Name: 
Barred Splitfin
Mexican Name: 
Pintito de Ocotlán
Original Description: 

  JORDAN, D. S. & J. O. SNYDER (1900): Notes on a collection of fishes from the rivers of Mexico, with description of twenty new species. Bulletin of the United States Fish Commission. 1899: pp 115-147

Holotype: 

  Collection-number: Leland Stanford Jr. University and Museum, Cat. No. LSUM-6163.

  The Holotype is an adult female, the standard length was not measured by the author. The type was collected by J. O. Snyder on December the 26th, 1898.

  Drawing of the Holotype of Chapalichthys encaustus:

Holotype of Chapalichthys encaustus

Terra typica: 

  The Holotype was caught in the Lago de Chapala near Ocotlán, federal state of Jalisco.

Etymology: 

  The epithet goes back to the ancient Greek with "énkaustos" (ἔγκαυστος) with the meaning burned in, from "en" (ἐν), which means "in", and "kaustós" (καυστός), burnt, from "kaíō" (καίω),  I burn. Jordan and Snyder chose the name probably due to the lateral stripes of adult fish, which look like brand marks.

Synonyms: 

Characodon encaustus   Jordan & Snyder, 1900

Distribution and ESU's: 

  The Barred Splitfin is endemic to the Mexican federal states of Jalisco and Michoacán. It is historically known from the lower Río Lerma drainage including the Río Lerma itself from about La Piedad and some affluents like the Río Duero and the canales dren Colesio, Zanja Madre and Moreño. It also occured in the Laguna de Chapala and adjacent sections of the Río Grande de Santiago to about the waterfalls at Juanacatlán E of Guadalajara, in the Laguna Cajititlán and a main affluent of the Laguna Chapala in the SW, the Canal Sahuayo including some dams in its headwaters (Presas Jaripo and Nueva). It disappeared from the ríos lerma and Grande de Santiago due to water pollution but still persists at most of the other places though sometimes in reduced numbers (Laguna de Chapala). Strongholds are the Lagos Los Negritos near Sahuayo and the dams around Jacona de Plancarte (Presas Verduzco and Orandino). The species can be found additionally in the Presa La Vega, upper Río Ameca drainage, but this is regarded as an introduced stock. The time and reason for the introduction are not completely solved. Though Chapalichthys were collected together with the types of Ameca splendens by Miller et al., in 1955 (Miller and Fitzsimons, 1971), it stayed almost unnoticed until the early years in this millenium when a single individual has been reported by P. Gesundheit in 2005 (Lyons, 2011). On a survey by Köck et al. in 2016, three adult fish were caught on the N end of the Presa La Vega. According to the affiliation to two river drainages, two subpopulations, the Laguna de Chapala (type subpopulation) and the Lower Río Lerma subpopulation, can be distinguished. The underlined names are the ones officially used by the Instituto Nacional de Estadística y Geografía; nevertheless, other ones might be more often in use or better known and therefore prefered.

 

    ESU ist short for Evolutionarily Significant Unit. Each unit expresses an isolated population with different genetic characteristics within one species.  ESU's can be defined by Molecular genetics, Morphology and/or Zoogeography and help in indicating different phylogenetic lineages within a species. The abbreviation for an ESU is composed of the first 3 letters of the genus, followed by the first 2 letters of the species name and an ongoing number in each species.

   In Chapalichthys encaustus, no different ESU's are distinguished, so all fish belong to Chaen1.

 

  The Laguna Chapala (green), Upper Río Grande de Santiago (blue) and Lower Río Lerma (yellow) subbasins on a Mexico map:

Laguna Chapala, Upper Río Grande de Santiago ans Lower Río Lerma subbasins

  The Barred Splitifn is known from the Lower Río Lerma subbasin including the Lower Río Lerma infrabasin (LLE), the Río Duero (DUE) infrabasin and the Jamay-Pajacuarán infrabasin (JPA). Within the Laguna Chapala subbasin, it is known from the Laguna Chapala infrabasin (CHA) and the Río Sahuayo infrabasin (SAH), within the Río Grande de Santiago subbasin from the Laguna Cajititlán infrabasin (CAJ), the Zapotlán del Rey infrabasin (ZAP) and (maybe) from the Zapotlanejo infrabasin (ZJO). The bold red line encompasses the species' distribution, the thin red lines separate the infrabasins. For a more detailed distribution, see the map for the Maximum Extent of Occurence (EOO):

Chapalichthys encaustus infrabasins

  Maximum Extent of Occurence of Chapalichthys encaustus:

Maximum EOO of Chapalichthys encaustus

Status : 

  International Union for Conservation of Nature (IUCN): Vulnerable

  Conservation status and population trends of Mexican Goodeids (Lyons, 2011): vulnerable/declining: "This species was formerly abundant throughout nearshore areas of Lake Chapala and was also encountered in adjacent areas of the Lerma and Santiago rivers and their tributaries (Lyons et al., 1998). Since the late 1990s, C. encaustus has disappeared from the mainstem Santiago and Lerma rivers due to pollution and has become much less common in Lake Chapala owing to the invasions of the non-native livebearers Poecilia sphenops and Gambusia yucatana, Poeciliidae (Becerra-Muñoz et al., 2003). Chapalichthys encaustus still persists in the lower portion of the Duero River drainage, a Lerma River tributary, including the La Luz and Orandino lakes, and also in Cajititlán and Los Negritos lakes, both near Lake Chapala. In 2005, a single individual was collected from La Vega Reservoir in the upper Ameca River basin, probably introduced during a stocking of blue tilapia, but there is no indication that C. encaustus has become established there (Pablo Gesundheit-Montero, Universidad Nacional Autónoma de Mexico, Mexico City, personal communication)."

  NOM-059-SEMARNAT-2010: no categoría de riesgo (no category of risk)

Habitat: 

  This fish lives in quiet waters of lakes, ponds and river channels, where currents are usually slow to none, but may be moderate. Vegetation there is usually sparse to none. When there is vegetation, it is composed of green algae, water hyacinths and Scirpus. The substrates are made of silt, mud, clay, sand and rocks. The waterbodies are rarely deeper than 1.3m, commonly the depth is less than 1m. The water can be from turbid to muddy (Miller, 2005). Brian Kabbes (Dec. 1998) caught this species in a channel in Michoacán. The water was muddy with the sight below 10cm, the water temperature around 16°C in the morning. In the Lago de Chapala, near the town of Chapala, he documented young fish, but few adults, probably because of the polluted waters near the town. On several surveys of the GWG to the Río Duero drainage (2014, 2016, 2017), the species was seen at Jacona de Plancarte in spring fed ponds, sometimes in big numbers, and was common in the Los Negritos pond in 2016.

Estancia de Igartua Estancia de Igartua

 Manantial La Luz Manantial La Luz

 Manantial La Luz Manantial La Luz

 Lago de Chapala Lago de Chapala

 Los Negritos pondLos Negritos pond

Biology: 

  Young fish with 9.0mm SL taken from Lago de Chapala on 26. March and a 16mm fish taken on 23. May suggest that the reproduction occurs during spring. Meek (1904) stated that young were born in the latter part of May, because he found 21 near-term embryos, each 10mm long, in a female of 68mm SL.

Diet: 

  The bifid teeth, the long convoluted gut and 20-28 slender gill rakers suggest, that the Barred Splitfin is herbivorous. Nevertheless, some people documented this species jumping out of the water and catching flying insects in the Chapala lake.

Size: 
The maximum known standard length is 93mm (Miller et al., 2005).
Colouration: 

  Jordan & Snyder described the colouration in their description: "Color in alcohol light yellowish-olive; 9 short and narrow dark vertical bands on median part of body; the first above base of pectoral; the ninth at base of caudal; scales on dorsal region of body edged with black dots; upper part of head dark; upper half of orbit black; opercles silvery; dorsal fin with a little dusky; other fins without dark color.” In life, the ground colour is somehow silvery shining. Adults have a yellow terminal band on the caudal fin, sometimes the pectoral fins appear yellow and females often have a yellow coloured venter.

Sexual Dimorphism: 

  At first appearance, males and females of the Barred Splitfin are not very easy to distinguish. The safest characteristic is the Splitfin in males, means the for Goodeinae typical mating organ formed by a notch after the first seven shortened rays of the Anal fin. Additionally, male Chapalichthys encaustus have a much bigger Dorsal fin than females. A difference in colouration is almost not visible, except for the sometimes more intense yellow coloured terminal band in the Caudal fins of males and a yellow belly in females, but these characters are not always visible and are changing with the individual. Females appear more slender than males. 

Chapalichthys encaustus male

Chapalichthys encaustus female

Remarks: 

  In older days, the fish were caught in the Chapala lake in masses, dried in the sun and eaten as dry fish refined with some sauces. Nowadays, it is much rarer and does no more play a role for human consumption. Hieronimus (1995, pl.4) recorded the species from the Río San Juan del Río, federal state of in Querétaro, which is a totally different drainage. This must be seen either as a misidentification or another interbasin transfer by human action. Earlier collections at this locality revealed two Cyprinid species and Goodea atripinnis. In France, an albinotic strain was selected and distributed in the Hobby for a while, but seemed to have disappeared again. Together with a recent (2018) selection of albinotic Chapalichthys pardalis in the Czech Republic, this was probably the only documented albinotic Goodeid.

Husbandry: 

  Looking on the biotopes of Chapalichthys encaustus, they suggest the species may prefer a habitat with moderate to none current, structured with rocks, roots and small areas with dense submerse vegetation. Intraspecific aggession is almost not observed, only sometimes between males of same size. Fry is rarely eaten, so it is possible to get fast a big and flock breeding colony. 

  The recommended tank size is at least 250 liters, bigger tanks with a generous base and little height (25cm are enough) are better for sure. A bit with roots and/or rocks structured tanks with few patches of dense submerse vegetation in the corners and bigger free areas to swim seem to do best with this species. The current should be none to moderate, especially as the oxygene level should be quite high (at least 8mg/l). 

  In the wild, adults of this species feed mainly from algae and aufwuchs, so much light to help algae grow and feeding with vegetables and additionally fiber-rich middle sized food from animalistic sources will be best for this fish. In aquarium, it feeds very well from flake food, granulate and tablets, additionally freeze dried food like Brine Shrimps is eaten greedy. The species is anything else but shy.   

  Concerning water quality, this species is in need of bigger water changes (60-80% every week) like most of the Goodeids, especially spring and river inhabiting species. Therefore an automatic water changing system can be helpful. Otherwise, in combination with constant temperatures higher than 24°C, fish may get sick, lose resistance against diseases and age too fast. So for keeping the strain healthy and strong, give the fish a rest during winter time with temperatures lower than 20°C for 2 or 3 months so they stop producing fry. In spring, when the temperature slowly increases, they will start spawning at 20 or 21°C and won't stop until it gets colder again or when it gets too warm (25°C).

  This species does very well when is kept in the open from spring to fall, starting when the water temperature by day exceeds 15°C and cold periods are no longer expected. Bring them out in the early afternoon, the time of the day with the highest water temperature. During the warm summer, reproduction will stop and may occur again in fall. Bring the fish in before the water temperature deceeds 15°C by day and keep them cool for the first days, then slowly raise the temperature but try to stay below 20°C over the winter time.

Locations