Leigh Marine Laboratory, University of Auckland, PO Box 349, Warkworth 0941, New Zealand.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2013 Jul;199(7):653-61. doi: 10.1007/s00359-013-0820-z. Epub 2013 Apr 25.
Swim bladder extensions and hearing ability were examined in the temperate reef fish Polyprion oxygeneios (hapuka). Using the auditory evoked potential (AEP) technique, hearing thresholds were determined in four age-classes of hapuka, from larvae to juveniles. The youngest age-class had poor hearing abilities, with lowest thresholds of 132 dB re 1 μPa, and a narrow auditory bandwidth (100-800 Hz). Hearing ability improved significantly throughout the remainder of their first year, including decreases in thresholds of up to 27 dB, and an increase in auditory bandwidth (up to 1,000 Hz). Magnetic resonance imaging (MRI) was used to investigate structural mechanisms that may account for this ontogenetic improvement in hearing. These showed rostral extensions of the swim bladder developing early in the juvenile stage, and extending with increasing age closer to the otic capsule. It is suggested that this indirect connection between the swim bladder and the otic capsule could impart pressure sensitivity closer to the inner ear, accounting for the increase in sensitivity seen during development, although further investigation of older fish is required for conclusive evidence. The improvement in hearing ability in hapuka could be potentially related to a unique life history of extended pelagic durations up to 4 years.
我们研究了温带珊瑚鱼多齿犬牙石首鱼（hapuka）的鳔延伸和听力能力。使用听觉诱发电位（AEP）技术，我们在从幼虫到幼鱼的四个年龄组中确定了 hapuka 的听力阈值。最年轻的年龄组听力能力较差，最低阈值为 132 dB re 1 μPa，听觉带宽较窄（100-800 Hz）。在它们的第一年中，听力能力显著提高，包括阈值降低高达 27 dB，以及听觉带宽增加（高达 1,000 Hz）。磁共振成像（MRI）用于研究可能解释这种听觉发育过程中改善的结构机制。结果表明，鳔的前向延伸在幼鱼阶段早期发育，并随着年龄的增长向耳囊延伸。有人认为，鳔和耳囊之间的这种间接连接可以使内耳更接近压力敏感部位，从而解释了发育过程中观察到的敏感性增加，尽管需要对年龄较大的鱼类进行进一步研究才能得出确凿的证据。hapuka 听力能力的提高可能与长达 4 年的独特海洋浮游生活史有关。
