Use of otolith microchemistry to identify subbasin natal origin and use by invasive Lake Trout in Yellowstone Lake

Abstract

Nonindigenous lake trout (Salvelinus namaycush) expansion in Yellowstone Lake has led to a large decline in the native Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri) population. We assessed whether otolith microchemistry could be used to identify subbasin natal origins and longterm use by lake trout as a potential tool for optimizing removal efforts. 87 Sr: 86 Sr and Sr:Ca ratios in otolith cores were used to assess natal origins and 87 Sr: 86 Sr ratios in otolith transects were used to assess movement patterns. Water chemistry was similar throughout the lake, ranging from 0.70634 to 0.70642 and 3.94 to 4.38 mmol/mol for 87 Sr: 86 Sr, and Sr:Ca ratios, respectively. Lake trout otoliths also showed little variation in 87 Sr: 86 Sr and Sr:Ca ratios of the natal region and 87 Sr: 86 Sr across otolith transects. Thus, we found that microchemical differences among Sr isotope and Sr:Ca elemental ratios in otoliths were insufficient to detect the natal origin or extensive within-lake movement that has been established from telemetry investigations. Detailed analysis of other elements or isotopes in hard-part microchemistry, in combination with other tools for detecting movement, may improve detection of natal origin and life history movement among fishes within freshwater lentic systems.

Evaluating 87Sr/86Sr isotope ratios and Sr mass fractions in otoliths of different European freshwater fish species as fishery management tool in an Alpine foreland with limited geological variability

“…Although partition factors between water and otolith Sr for selected non-European freshwater salmonids exist (Wells et al, 2003;Muhlfeld et al, 2012;Stewart et al, 2021) only individual data sets for comparable typical European freshwater fish species are currently available (Melancon et al, 2009). Partition factors documented in this study were 0.420 ± 0.057 SD for Coregonus spp., 0.465 ± 0.136 SD for cyprinids, 0.275 ± 0.069 SD for P. fluviatilis, and 0.496 ± 0.145 SD for R. rutilus.…”

“…(2007) described a partition factor of 0.37 for arctic grayling Thymallus arcticus which is comparable to the value of 0.345 ± 0.067 SD documented for T. thymallus in this study. The discrimination factors for typical non-European salmonids documented in literature range from 0.28 for Lake trout Salvelinus namaicush (Melancon et al, 2009), 0.285 ± 0.047 SD for westslope cutthroat trout (Oncorhynchus clarkii lewisi) (Muhlfeld et al, 2012), 0.29 for nonindigenous lake trout in the Yellowstone park (Salvelinus namaycush) (Stewart et al, 2021) to 0.4 for field-sampled westslope cutthroat trout O.…”

“…Besides the documented species-specific effects, intraspecific differences in the uptake ratio of Sr caused by environmental conditions in habitats or simply by the age/size affecting the protein synthesis in relation to the crystallization rate of the otolith might be also existing (Campana, 1999). For example, an increasing trend of the Sr/Ca ratio with fish size independent of environmental variability indicating difference in elemental uptake with age was documented for a salmonid species only recently (Stewart et al, 2021). Basically, discrimination of elements can occur at three physiological barriers in freshwater fish, from water to gill, from blood to endolymph liquid and finally from endolymph to the otolith via the crystallization process (Campana, 1999;Melancon et al, 2009).…”

“…Partition coefficients between environmental and otolith Sr/Ca ratios are usually used to describe elemental discrimination caused by physiological barriers during elemental uptake and incorporation in otoliths (Campana, 1999). Sr to Ca partition coefficients can be used for predicting otolith Sr/Ca values from water samples and assess the potential influence of different factors on elemental uptake (Stewart et al, 2021). Moreover, it is relevant which of the three pairs of otoliths in fishes (i.e., asteriscus, lapillus, sagitta) is used for a specific species, as potential differences in their calcium carbonate polymorphs (aragonite, vaterite, calcite) need to be considered (Pracheil et al, 2019).…”

What is the relationship between hypoxia, water chemistry and otolith manganese content?

“…Thus, otoliths are widely used in research related to environmental changes. For example, otolith morphology is an aspect of ocean acidification (Bignami et al ., 2013; Munday et al ., 2011), and otolith microchemistry has been used extensively to determine origin (Stewart et al ., 2021), spawning site (Turcotte & Shrimpton, 2020), migration and life history (Austin et al ., 2019) of fish. In addition, the concentrations of different elements in otoliths have been used to examine many environmental factors.…”