Bourret S L, Kennedy B P, Caudill C C, Chittaro P M
Department of Fish and Wildlife Sciences, University of Idaho, Moscow, ID, 83843-1136, U.S.A.
J Fish Biol. 2014 Nov;85(5):1507-25. doi: 10.1111/jfb.12505. Epub 2014 Sep 17.
Isotopic composition of (87) Sr:(86) Sr and natural elemental tracers (Sr, Ba, Mg, Mn and Ca) were quantified from otoliths in juvenile and adult Chinook salmon Oncorhynchus tshawytscha to assess the ability of otolith microchemistry and microstructure to reconstruct juvenile O. tshawytscha rearing habitat and growth. Daily increments were measured to assess relative growth between natal rearing habitats. Otolith microchemistry was able to resolve juvenile habitat use between reservoir and natal tributary rearing habitats (within headwater basins), but not among catchments. Results suggest that 90% (n = 18) of sampled non-hatchery adults returning to the Middle Fork Willamette River were reared in a reservoir and 10% (n = 2) in natal tributary habitat upstream from the reservoir. Juveniles collected in reservoirs had higher growth rates than juveniles reared in natal streams. The results demonstrate the utility of otolith microchemistry and microstructure to distinguish among rearing habitats, including habitats in highly altered systems.
对幼年和成年奇努克鲑（Oncorhynchus tshawytscha）耳石中的锶同位素组成（⁸⁷Sr:⁸⁶Sr）以及天然元素示踪剂（锶、钡、镁、锰和钙）进行了定量分析，以评估耳石微化学和微结构重建幼年奇努克鲑的养殖栖息地和生长情况的能力。测量了日生长增量，以评估出生养殖栖息地之间的相对生长情况。耳石微化学能够区分幼年鲑在水库和出生支流养殖栖息地（源头流域内）的栖息地利用情况，但无法区分不同集水区之间的情况。结果表明，返回威拉米特河中游的非孵化场成年鲑中，90%（n = 18）在水库中养殖，10%（n = 2）在水库上游的出生支流栖息地中养殖。在水库中采集的幼年鲑比在出生溪流中养殖的幼年鲑生长速度更快。结果证明了耳石微化学和微结构在区分养殖栖息地方面的实用性，包括高度改变系统中的栖息地。
