University of California, Davis, USA.
University of California, Santa Cruz, USA.
Sci Rep. 2022 Dec 1;12(1):20751. doi: 10.1038/s41598-022-22813-w.
Developmental abnormalities in otoliths can impact growth and survival in teleost fishes. Here, we quantified the frequency and severity of developmental anomalies in otoliths of delta smelt (Hypomesus transpacificus), a critically endangered estuarine fish that is endemic to the San Francisco Estuary. Left-right asymmetry and anomalous crystalline polymorphs (i.e., vaterite) were quantified and compared between wild and cultured populations using digital image analysis. Visual estimates of vaterite were validated using X-ray diffraction, Raman spectroscopy, laser ablation ICPMS, and electron probe microanalysis. Results indicated that cultured delta smelt were 80 times more likely to contain a vateritic otolith and 18 times more likely to contain relatively large (≥ 15%) amounts of vaterite. Similarly, cultured fish exhibited 30% greater asymmetry than wild fish. These results indicate that cultured delta smelt exhibit a significantly higher frequency of vestibular abnormalities which are known to reduce fitness and survival. Such hatchery effects on otolith development could have important implications for captive culture practices and the supplementation of wild fish populations with cultured individuals.
耳石发育异常会影响硬骨鱼类的生长和存活。在这里，我们量化了濒危河口鱼类——太平洋鱒（Hypomesus transpacificus）耳石发育异常的频率和严重程度。我们使用数字图像分析比较了野生和养殖种群之间的左右不对称和异常结晶多形体（即文石）。使用 X 射线衍射、拉曼光谱、激光烧蚀 ICPMS 和电子探针微分析验证了文石的目视估计。结果表明，养殖的太平洋鱒含有文石耳石的可能性高 80 倍，含有相对较大（≥15%）文石的可能性高 18 倍。同样，养殖鱼类的不对称性比野生鱼类高 30%。这些结果表明，养殖的太平洋鱒表现出更高频率的前庭异常，已知这种异常会降低适应性和存活率。这种养殖方式对耳石发育的影响可能对圈养养殖实践以及用养殖个体补充野生鱼类种群具有重要意义。
