Hybrid Catfish Discussion thread.

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wednesday13 said:
Ill waterchange tommorow and get some real pics its hard enough to see em on the black liner...i may pull them out for a closer look, i have 2 that may b a good debate.

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Sounds awesome!!! Then you can get some measurement pics and vids too!!! ;) I love seeing big kitties get measured!!! I know the feeling with the black liner. My new pond with it. I love it but had to put some light colored tile in there for better fish viewing as I didn't want sand.
 
necrocanis said:
Just found evidence that there is this hybrid also. :)

Pseudoplatystoma corruscans × Pseudoplatystoma reticulatum
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Here is the abstract from the paper I am citing for this hybrid. I am currently trying to track down confirmed pics of this hybrid as well......more later


Genetic divergence between Pseudoplatystoma corruscans and Pseudoplatystoma reticulatum (Siluriformes: Pimelodidae) in the Paraná River Basin
Braz. J. Biol. vol.69 no.2 supl.0 São Carlos June 2009



Abstract:

Pseudoplatystoma corruscans (Spix and Agassiz, 1829) and Pseudoplatystoma reticulatum (Eingenmann and Eigenmann, 1889) are large migratory catfishes of high biological importance and great commercial value in South America. Because fertile crossbreeds can be artificially produced in hatcheries, a high genetic proximity between these two Pimelodidae species is conceivable. Possible escape of crossbred specimens from pisciculture stations is a serious environmental concern. Despite their importance, knowledge of P. corruscans and P. reticulatum biology, ecology, population diversity and genetics is limited. In the present work, the genetic divergence between P. corruscans and P. reticulatum populations from the Paraná River Basin was analyzed on the basis of polymorphisms in ISSR fragments and in the hypervariable sequence of the mitochondrial DNA (mtDNA) control region. Estimates of intraspecific haplotype (h > 0.5) and nucleotide diversities (&#960; < 0.01) indicate that P. corruscans and P. reticulatum have survived a historical population decline, followed by a demographic expansion. The interspecific polymorphisms within the mtDNA control region and ISSR fragments were suitable as diagnostic molecular markers and could be used to discriminate the two species. A unique Pseudoplatystoma specimen, captured in the Upper Paraná River Floodplain, was identified by these DNA diagnostic markers as a hybrid P. reticulatum x P. corruscans, which possibly escaped from pisciculture. The integrity of the natural population of P. corruscans in the Upper Paraná River is at risk of genetic introgression or homogenization due to the presence of hybrids and the transposition of P. reticulatum upstream through the Canal da Piracema at Itaipu Dam. Data presented herein improve the understanding of the genetic relatedness between P. corruscans and P. reticulatum and represent potential tools for future programs of conservation and surveillance of genetic introgression events and the genetic integrity of these populations.

The full, and kind of boring document can be read at this link.
http://www.scielo.br/scielo.php?pid=S1519-69842009000300022&script=sci_arttext

For future note if I ever mention something without citing a reference can someone make me put my money where my mouth is and post up something to back what I am saying? :) I want to make sure that if it is a confirmed hybrid that I am able to provide the evidence as confirmation. With this one I will try to go a step farther and find some pics as it is cultured as well. That is supported within this doc also. I'm goin hunten!!!!
 
The above doc also states that P. reticulatum is the mother species, and P. corruscans is the father species.
 
Ok so while digging around for some other stuff I found the old doc I was looking for about RTC x TSN and RTC x Leiarius that shows which species were used, and confirms what I said previously about which species were used. Now remember that this was first generation hybrid produced back in 1996 so these two hybrids can be trace back at least that far. I am working on getting the full doc so that I can see if it mentions anything about other hybrids that were produced during this test run of sorts. Here is the abstract:

Reproduccion inducida del Bagre Cajaro y avances sobre su hibridacion con dos especies de pimelodidos (Piscis, siluriformes)
Date of publication Ene-Abr 1996

The redtailed catfish Phractocephalus hemiliopterus (Block & Schneider, 1801) is one of the more impotant species from freshwater fisheries of Venezuela. The objetives of this research were 1.- Spawning in cautivity of P. hemiliopterus 2.- Hybridization of P. hemiliopterus with two species of close phylogenity. It was performed two essays, the first one was carried out to reproducction of P. hemiliopterus as sepecies and for crossing with Pseudoplatystoma fasciatum, the second one for hybridization with Leiarius marmoratus. The spawnings were reached through hypophysation techniques by using carp pituitary extract. The results point out that the spawning ocurred at 196,8 hour-grade. Also the embryonic development lasted 20 hours and 50 minutes at 25,6 +- 0,2 ºC. The red coloration of caudal fin of adults began over 75 days of life in the fingerlings. Regarding the intergeneric crossings, we did not note severe incompatibles on embrionic development. In orther hand, it was observed high canibalistic behavior in larvae and fingerlings which it severely decreased the number of larvae hatched at the begining in P. hemiliopterus and hybrids. In that sense, the hybridizations gained, it does not appear to improve the rate of surviving with regard to the control P. hemiliopterus.

One thing I have noted while doing some research today is a little off the subject of hybrids, but still interesting. It seems that comparatively the embryonic development stages of these large pimelodid catfish are for the most part less than 24 hours. This amazes me. From my research tsn takes about 15-18 hours, rtc takes about 20-22 hours and here the hybrid takes about 20-21 hrs. :)

Abstract found here:

http://agris.fao.org/agris-search/search/display.do?f=1999/VE/VE99001.xml;VE1999000026
 
What a great day for discovery in the realm of catfish hybrids lol. I think my research techniques are quit honed at this point. :) Ok so now for the other new hybrid of the day lol. This one is Phractocephalus hemioliopterus x Pseudoplatystoma reticulatum........ This is just a test to see if it is a viable hybrid for the food industry. You will note the paper is in Portuguese. I translated and read it. Apparently it had viable growth rate for production in the aquaculture, and high survival rate. This paper is not dated for some reason, and just seems a quick summary. It does however have pics of the parents used and of the hybrid. No surprise that the hybrid looks very similar to P. hemioliopterus x P. fasciatum. Maybe a slight difference in patterning and head shape, but for the most part indistinguishable from the other. Here is the link so you may view the pics.

http://prope.unesp.br/xxi_cic/27_32723332829.pdf
 
Leiarius marmoratus x Pseudoplatystoma fasciatum
Calophysus macropterus x Leiarius marmoratus,
C. macropterus x Pimelodus blochii,
C. macropterus x Pseudoplatystoma fasciatum,
P. fasciatum x P. blochii.

These hybrids are all supported in this document which has given me another doc to examine farther as well lol. This also supports the species used with a surprise of also having vulture catfish in the mix as well!!!!! I have yet to see the evidence of this species in a hybrid thus far in pics that is. Obviously it was done here though. Here is the doc. I am referencing.

Revista AquaTIC, nº 21 - 2004
Mónica Botero
2
, Adriana Fresneda
1
, Andrés F. Montoya
1
, Martha Olivera-Angel
1

Link:
http://www.revistaaquatic.com/aquatic/pdf/21_07.pdf
 
This is also very interesting. Apparently there has be a strive in this hybrid lately as well. :) P. gigas x P. hypopthalmus!!!!!! I will also try to get some pics of this hybrid.

Here is the abstract. Curious is that it points out that in a 2.5 year controlled study of growth, P. gigas averaged 8 kg bw, P. hypopthalmus averaged 2 kg bw, and the hybrid averaged 3.5 kg bw. i think this lends to another thread on here of the discussion of growth rates of P. hypopthalmus also.

Morphological comparisons, meristic counts and measurements of the parental species (Pangasius gigas and P. hypopthalmus) and the hybrid were presented. Gut contents, the gastrointestinal tract (GIT), growth and carcass compositions were also studied. The live weight of the 2.5-year-old farm-raised fishes were significantly different among parental species and hybrid, with P. gigas (8 kg) being the largest, the hybrid (3.5 kg) intermediate and P. hypopthalmus (2 kg) the smallest. P. gigas had the he combined weights of the fillets and belly flap roughly the same in percentage (52-53 percent) as those of the hybrid (49 percent), but higher than that of P. hypopthalmus (47 percent). There was no significant difference among the fillets of subadults in the percentages of protein and moisture. The fat content of fillets was significantly higher in P. gigas (3 percent) than in the hybrid (0.6 percent) and P. hypopthalmus (0.3 percent). Since there were no stomach contents in the wild adult of P. gigas examined within 3 h after capture and the subadult P. gigas had remarkedly high fillet fat content, these suggests that wild adult of P. gigas could accumulate a large amount of energy reserves and perhaps do not feed regularly prior to the spawning migration.

Abstract taken from here:

http://agris.fao.org/agris-search/search/display.do?f=2004/TH/TH04028.xml;TH2001001817
 
OMG!!!!! lol, you guys won't believe the next hybrid I will be introducing today!!!!!!!!!!!!!!!! I am shocked!!!! I have to see/obtain one somehow lol.
 
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