Department of Biology, University of Victoria, Victoria, British Columbia, Canada.
Pacific Salmon Foundation, Vancouver, British Columbia, Canada.
J Fish Biol. 2023 Apr;102(4):870-882. doi: 10.1111/jfb.15329. Epub 2023 Feb 7.
Many aspects of natural and hatchery origin salmonid genetics, physiology, behaviour, anatomy and life histories have been compared due to the concerns about what effects domestication and hatchery rearing conditions have on fitness. Genetic and environmental stressors associated with hatchery rearing could cause greater developmental instability (DI), and therefore a higher degree of fluctuating asymmetry (FA) in various bilaterally paired characters, such as otoliths. Nonetheless, to appropriately infer the effects of DI on otolith asymmetry, otolith mineralogy must be accounted for. Vateritic otoliths differ substantially from aragonitic otoliths in terms of mass and shape and can artificially inflate any measurement of FA if not properly accounted for. In this study, measurements of otolith asymmetry between hatchery and natural origin Coho salmon Oncorhynchus kisutch from three different river systems were compared to assess the overall differences in asymmetry when the calcium carbonate polymorph accounted for 59.3% of otoliths from hatchery origin O. kisutch was vateritic compared to 11.7% of otoliths from natural origin O. kisutch. Otolith mineralogy, rather than origin, was the most significant factor influencing the differences in asymmetry for each shape metric. When only aragonitic otoliths were compared, there was no difference in absolute asymmetry between hatchery and natural origin O. kisutch. The authors recommend other researchers to assess otolith mineralogy when conducting studies regarding otolith morphometrics and otolith FA.
由于担心驯化和孵化条件对适应性的影响，人们对鲑鱼的许多方面，包括其遗传、生理、行为、解剖和生活史等方面进行了比较。与孵化有关的遗传和环境压力因素可能导致更大的发育不稳定性（DI），从而在各种双侧配对特征（如耳石）中产生更高程度的波动不对称（FA）。然而，为了正确推断 DI 对耳石不对称的影响，必须考虑耳石的矿物学特性。方解石质耳石与文石质耳石在质量和形状上有很大的不同，如果不加以适当考虑，可能会人为地夸大 FA 的任何测量值。在这项研究中，比较了来自三个不同水系的孵化和天然起源的银鲑耳石的不对称性测量值，以评估在考虑到孵化起源的 O. kisutch 的 59.3%的耳石为方解石质，而天然起源的 O. kisutch 的耳石只有 11.7%为文石质时，不对称性的总体差异。耳石的矿物学特性而不是起源是影响每个形状度量不对称性差异的最重要因素。当仅比较文石质耳石时，孵化和天然起源的 O. kisutch 之间的绝对不对称性没有差异。作者建议其他研究人员在进行耳石形态计量学和耳石 FA 研究时，评估耳石的矿物学特性。
