Sex matters: Otolith shape and genomic variation in deacon rockfish (Sebastes diaconus)

Little is known about intraspecific variation within the deacon rockfish (Sebastes diaconus), a recently described species found in the northeast Pacific Ocean. We investigated population structure among fish sampled from two nearshore reefs (Siletz Reef and Seal Rock) and one offshore site (Stonewall Bank) within a <50 km2 area off the Oregon coast. Fish from the three sample sites exhibited small but statistically significant differences based on genetic variation at >15,000 neutral loci, whether analyzed independently or classified into nearshore and offshore groups. Male and females were readily distinguished using genetic data and 92 outlier loci were associated with sex, potentially indicating differential selection between males and females. Morphometric results indicated that there was significant secondary sexual dimorphism in otolith shape, but further sampling is required to disentangle potential confounding influence of age. This study is the first step towards underst...目前学界对迪肯平鲉（deacon rockfish, Sebastes diaconus）的种内变异认知仍较为有限，该物种是近年正式被描述的、分布于东北太平洋海域的新类群。本研究针对俄勒冈州沿岸不足50平方千米海域内的样本开展种群结构分析，采样位点涵盖两处近岸礁体——锡利茨礁（Siletz Reef）与海豹岩（Seal Rock），以及一处远海站位石墙滩（Stonewall Bank）。基于超过15000个中性基因座（neutral loci）的遗传变异分析显示，三处采样点的个体虽仅存在微小差异，但该差异具有统计学显著性；无论对样本单独解析还是将其划分为近岸、远海群组进行分析，结果均保持一致。借助遗传数据可便捷区分雌雄个体，另有92个异常基因座（outlier loci）与性别相关联，这一结果或提示雌雄个体间存在差异化选择压力。形态测量结果表明，耳石（otolith）形态存在显著的第二性征二态性，但仍需进一步采样以厘清年龄因素可能带来的混杂影响。本研究为深入理解该物种相关议题迈出了第一步。