https://doi.org/10.1111/faf.12751
https://onlinelibrary.wiley.com/doi/10.1111/faf.12751
Perhaps the most eye-catching image in the paper:Abstract
Ernst Weber stated in 1819, based on dissections, that the swimbladder in the European wels (, Siluridae) and related cyprinids serves as an eardrum and that the ossicles connecting it to the inner ear function as hearing ossicles similar to mammals. In the early 20th century, K. von Frisch showed experimentally that catfishes and cyprinids (otophysines) indeed hear excellently compared to fish taxa lacking auxiliary hearing structures (ossicles, eardrums). Knowledge on hearing in catfishes progressed in particular in the 21st century. Currently, hearing abilities (audiograms) are known in 28 species out of 13 families. Recent ontogenetic and comparative studies revealed that the ability to detect sounds of low-level and high frequencies (4–6 kHz) depends on the development of Weberian ossicles. Species with a higher number of ossicles and larger bladders hear better at higher frequencies (>1 kHz). Hearing sensitivities are furthermore affected by ecological factors. Rising temperatures increase, whereas various noise regimes decrease hearing. Exposure to high-noise levels (>150 dB) for hours result in temporary thresholds shifts (TTS) and recovery of hearing after several days. Low-noise levels reduce hearing abilities due to masking without a TTS. Furthermore, auditory evoked potential (AEP) experiments reveal that the temporal patterns of fish-produced pulsed stridulation and drumming sounds are represented in their auditory pathways, indicating that catfishes are able to extract important information for acoustic communication. Further research should concentrate on inner ears to determine whether the diversity in swimbladders and ossicles is paralleled in the inner ear fine structure.
FIGURE 3: Experimental setup demonstrating that catfish (and minnows) hear better than humans under similar conditions. Brown bullheads detected whistling sounds at distances of up to 65 m (minnows up to 75 m) as compared to 50 m in humans. The future Nobel laureate Karl von Frisch is standing on the left. Experiments were conducted in a 120-m-long hallway at the Institute of Zoology at the University of Munich. From Stetter (1929).
