Pseudoplatystoma X Leiarius hybrids on the loose!

[lfinley58]

Yabu, M.H.S., Vidotto-Magnoni, A.P., Casimiro, A.C.R., Garcia, D.A.Z., Costa, A.D.A., Prado, F.D.D., Porto-Foresti, F., & Orsi, M.L. 2018. First record of non-native hybrid catfish Pseudoplatystoma reticulatum × Leiarius marmoratus in the Upper Paraná River basin, Brazil. Journal of Fish Biology 92: 261–267.
The aim of this study is to report the presence of a three non-native hybrid long-whiskered catfishes
(family Pimelodidae) in the Upper Paraná River basin, Brazil. Genetic analyses demonstrated that the
three presumptive hybrids were a result of the crossbreeding of Pseudoplatystoma reticulatum (central
Amazonas River basin and Lower Paraná River) and Leiarius marmoratus (Amazonas, Essequibo and
Orinoco rivers), producing a hybrid commonly known in Brazil as cachandiá. The potential threat to
biodiversity, due to possible genetic contamination, competition and predation of wild stocks, of such
artificially produced hybrid fishes is discussed.
Open access at:
http://onlinelibrary.wiley.com/doi/10.1 ... 13505/epdf

This is not a pretty picture! Actually, the fish pictured is quite attractive but the potential of this situation is very ugly.
Lee

[Bas Pels]

Reading the articel I start to miss something - information on the fertility of this hybrid

Hybrids grow fast, and so on, because they don't spend energy on reproducing. That is, hydrids are assumed to be infertile.

But if they are infertile, how can they contaminate the related genepools? I realize there is something between fertile and infertile, but if the advantages of using hybrids are based on the infertility of the individuals. That is, a semi fertile hybrid will not be as interesting for aquaculture as a fullly infertile one.

Competition is obviously a problem, but I think it is better to have a few hybrids escaping than a similar number of pure individuals.

However, if a lot of hybrids were to excape, the competition would be a problem. That is, one should never let hybrids loose in nature instead of in a controled pond.

But I think it is much better to find 3 hybrids than 3 non-hybrids - these could reproduce and really become a problem

[lfinley58]

It will be interesting to see any further work regarding the potential (or real) fertility of some of these critters. Obviously the authors have taken that into consideration. Certainly, hybrids in both some cichlids and catfishes have been shown to be fertile.
In the current situation hopefully all will work out well - but in a phrase "to be continued."

Lee