Does this provide strategies for finding fish when collecting in So America?

[bekateen]

Benejam, L., Tobes, I., Brucet, S., & Miranda, M. (2018). Size spectra and other size-related variables of river fish communities: systematic changes along the altitudinal gradient on pristine Andean streams, Ecological Indicators, 90, 366-378.

https://doi.org/10.1016/j.ecolind.2018.03.012.
(http://www.sciencedirect.com/science/ar ... 0X1830164X)

HIGHLIGHTS

• Size spectra and size-related variables of river fish communities as bioindicators.
• Systematic changes of size-related variables occurred along altitudinal gradient.
• Body size structure an alternative to the taxonomic approach to assess biodiversity.

ABSTRACT
The estimation of biodiversity is complex in remote areas like Andean-Amazon piedmont where the lack of knowledge is noticeable and most species have not yet been identified. An alternative to the taxonomical approach to assess biodiversity and community structure is to study the body size structure of the community. The present study aimed to identify systematic changes of the size structure of fish communities along the altitudinal gradient of pristine Andean streams. At the same time, we assessed if size structure of fish communities could be an alternative or complementary approach to traditional taxonomic metrics of ecological assessment. This study was conducted along two rivers of eastern Andean piedmont: Hacha River and Alto Madre de Dios basin. Our analysis showed lower values of total size range, maximum length and number of size classes in the highest places and increasing in lower reaches of the rivers. Concerning abundance size spectra, we found flatter slopes (indicating higher relative abundance of large fish) and lower coefficient of determination (i.e. less linear size spectra) and intercept at y-axis on upstream reaches. On the other hand, fish abundance, species richness and species diversity increasing from upstream to downstream. These systematic changes on size-related variables were similar using both basins together or independently and may be used in future studies as management reference conditions when assessing the effect of perturbations in freshwater ecosystems, while bypassing the error associated with the lack of taxonomic information.

• Keywords: Andean piedmont; Headwaters; Body size; Pristine rivers; Fish; Biodiversity

My own thoughts on this paper: Although perhaps being imposing for its heavy reliance on metrics and statistics, this paper provides three benefits to the hobbyist and collector:

• It provides specific data on water conditions (temp, current velocity, conductivity, substrate, etc.) from multiple locations along the two basins sampled. This could help people who keep fish from nearby areas.
  
• The paper attempts to correlate certain hydrodynamics and river properties with the abundance, types, and sizes of fish found in these areas.... I.e, what kinds of fish are going to be found in flat areas or areas with steeper slopes (and potentially faster currents)?
  
• It provides a list of fish genera (not just catfishes, but definitely including catfishes) that are found in these areas.

I wonder if points #2 and #3 (above) might provide guidance to people on collecting trips when they are searching for new places to look for Ancistrus vs. Corydoras vs. Chaetostoma, etc. Although I expect such info is already available as "head knowledge" by the locals and by experienced collectors (e.g., ideas like "this stream (or that stream) will (or will not) be a good habitat for genus X"), the details in this paper might help collectors put their knowledge into words; and in my imagination, this could allow them to strategically look for new places to find fish.

I've never (yet ) been in the field collecting fish, so maybe either all this is not rocket science, or maybe it has no practical application. But as I read the paper, it seems like there's some really good quantitative and qualitative analysis in here for these purposes I listed above. For those of you who have collected, I'm curious: Would this type of info be helpful?
If so, how, and if not, why not? Thanks

[-carlo]

I have no experience collecting fish. But I found a youtube channel of a guy who does (i think) and makes videos of fish in their natural habital in South America. His name is Ivan Mikolji. Maybe he can help you out if you message him.

No ideo if this is of any use to you but I wish you the best of luck!