Length–weight and length–length relationships for 135 fish species from the Xingu River

[TwoTankAmin]

The following Technical Contribution was published in J. Appl. Ichthyol. (2015), 1–10.
Length–weight and length–length relationships for 135 fish species from the Xingu River (Amazon Basin, Brazil)

Summary
Length–weight (LWR) and length–length relationships (LLR) are presented for 135 freshwater fish species sampled by several types of fishing gear between April 2012 and July 2014 in the middle and lower Xingu River Basin, northern Brazil. The report represents the first references on LWRs and LLRs for 114 and 119 species, respectively, and also provides a new maximum size for 96 species.

The full paper can be found here: http://www.researchgate.net/profile/Mar ... 6a548f.pdf

The paper contains the data for all of the species they collected between the confluence of the Rio Iriri and the Xingu down to below the Belo Monte Falls to about Senador Jose Porfirio. What I am curious about is the fact that there is only one Hypancistrus species listed in the list of Loricariidae. I was under the impression that there was more than one species of Hypancistrus found in the Xingu within the range studied. Am I wrong in thinking this, are all the other Hypans found below the area of near Senador Jose Porfirio?

[Silurus]

The sampling methods are not optimal for Hypancistrus, which may explain why they caught only one species. It's also likely that the authors did not sample the microhabitats with the greatest Hypancistrus species diversity.

[TwoTankAmin]

The sampling methods are not optimal for Hypancistrus

That is what I thought as soon as I read them. However, given how much zebras love to hide and that they are smaller than most Hypans, I wondered how those methods were effective in catching some of them but not any other Hypans. The microhabitat explanation may be the reason.

But the other conclusion here then could be that there are likely a number of plecos and perhaps other species that their capture methods and location selection were likely to have missed. Considering there is only one river being explored and that they did not sample the full length, I wonder how many species may actually inhabit the Xingu and how many of them might be lost to to the dam project.