Stridulation sounds of Lophiosilurus alexandri

[bekateen]

Raick, X., Kurchevski, G. & A.L. Godinho. (2025). Stridulation sounds of the pacamã Lophiosilurus alexandri Steindachner, 1876 (Pseudopimelodidae), a threatened endemic Brazilian catfish. Journal of Fish Biology. https://doi.org/10.1111/jfb.70001

https://onlinelibrary.wiley.com/doi/ful ... /jfb.70001

VIDEO of live fish: Video S1. Dorsal view of Lophiosilurus alexandri in a glass tank to observe the movement of the pectoral fins.

Abstract
Pseudopimelodidae comprises 49 species of freshwater catfish endemic to South America, with limited research on their acoustic behaviour. This study focuses on the pacamã

Lophiosilurus alexandri

Steindachner, 1876, a vulnerable catfish species endemic to the São Francisco River basin, known for its ecological and economic importance. Sound production by this species was analysed for the first time. Three individuals were recorded while being held underwater revealing the production of two distinct sound types (type I and type II) associated with pectoral fin movements (abduction and adduction). Sounds were 85–135 ms long with a variable number of pulses or peaks. Type II sounds were longer and louder than type I sounds, with both types showing a similar peak frequency ranging between 200 and 500 Hz. The sounds were produced alternately by the pectoral fins, with occasional lateralization. More research is needed to determine whether these sounds can be used for monitoring or if they lack sufficient species-specific characteristics.

[yellowcat]

Thanks for posting this, Eric! I have a pair of adults, @ 18" or so, kept for 2 1/2 years. Very timely this, about a week ago I heard a strange noise coming from their 130G tank, a low to mid frequency 'grinding' sound, two times for maybe 10 then 5 seconds in duration. At first I thought it might be a problem with my filter but it seems it wasn't after all. I can now conclude it was coming from one or both fishes? I do hear these fish moving gravel around which includes their habit of burying themselves in it as they like to do at times but nothing like what I heard that one time. Too many species of catfish to mention, commonly make stridulation(new word to me!) sounds, for a variety of reasons to be sure, if nothing else, from stress when caught by anglers or being netted by aquarists. The loudest fish I've ever kept was a freshwater lion fish, making a roaring sound that could be heard from the next room! Anyway, nice to know that what I heard wasn't my imagination... Pictures of my pair: