Ontogenetic shifts in growth and habitat use of freshwater Coastal Cutthroat Trout revealed through otolith analysis of multiple elements

This dataset contains otolith microchemistry transects and derived
products for adfluvial Coastal Cutthroat Trout (Oncorhynchus clarkii
clarkii) sampled in the Comox Lake–watershed system (Vancouver Island,
BC). Raw transects for stream-caught juveniles and lake-caught adults were
acquired as elemental concentrations (ppm) and converted in this workflow
to molar ratios (element, mmol/mol) for Mg, Mn, Zn, Sr, Ba (Li included
where available). Primordia and check positions (e.g., first winter) were
compiled from microscope-based measurements for both adults and juveniles,
enabling extraction of life-stage-specific windows (e.g., natal/rearing
sections) along each transect. We use multiple analytical tracks. (1)
Natal origin discrimination: After cleaning and unit conversion, we
compute OTF-level means over a standardized rearing window and
log-transform elements for MANOVA/ANOVA with Tukey HSD across capture
sources; letters are overlaid on boxplots to summarize pairwise
differences. We then fit linear discriminant functions (LDFA) on juvenile
rearing means (Sr, Ba, Mn, Mg; Zn available in the data and plots) and
apply the trained model to adult lake fish to estimate natal
contributions, reporting jackknife confusion matrices, posterior
probabilities, and assignment summaries. (2) Movement/habitat signal
detection: We assess Mn spikes as putative indicators of habitat shifts
(e.g., stream→lake entrance) using a hybrid rule (rolling mean +
individual mean fallback), summarizing spike count, magnitude, start/end
locations, and before/after contrasts within fish. (3) Zn
oscillations as annulus proxies by linking Zn inflection distances to
visually measured annulus starts (1–5AL) and fitting per-annulus simple
linear models, reporting coefficients, r², model p-values, and slope-≈1
tests. Together, the dataset and scripts support reproducible conversion,
QC, visualization of transects, hypothesis testing across sources,
discriminant assignment of adults, and mechanistic exploration of Mn and
Zn features as indicators of habitat transitions and age structure.