Thermal habitat use and juvenile growth of Svalbard Arctic charr: evidence from otolith stable oxygen isotope analyses

Abstract

Stable oxygen isotopes (d 18 O) derived from otoliths were used to estimate mean annual water temperatures experienced by individual Svalbard Arctic charr, Salvelinus alpinus (L.), during their first four growth seasons. The analysed Arctic charr experienced a high variety of temperatures, indicating the use of different thermal habitats. A higher proportion of the juveniles experienced warmer temperatures during their first summer compared with later summers, suggesting the selective use of the shallowest littoral areas of the lake. Although the estimated temperatures were consistent with water temperatures found in High Arctic rivers and lakes during summer, they did not represent the annual variation in air temperature registered over the 20 years of otolith measurement. Furthermore, summer otolith increment width did not correlate with the experienced temperature. However, after the second year, otolith increment width was highly dependent on increment width during the previous summer. This study estimated mean summer water temperatures experienced by individual Arctic charr during the first four growth seasons providing additional evidence that stable oxygen isotope analysis can be used to provide insight into the thermal habitat use by juvenile Arctic charr.

Calibrating temperature reconstructions from fish otolith oxygen isotope analysis for California's critically endangered Delta Smelt

“…In this study we used high‐resolution SIMS micro‐probe analysis of fine‐scale changes in oxygen isotope ratios (δ 18 O values) to parameterize a species‐specific model to estimate ambient water temperatures from otoliths of the critically endangered Delta Smelt. Our results support the findings of previous studies, showing that δ 18 O values in otoliths primarily reflect those of the ambient water and can provide a reliable proxy to reconstruct past water temperatures . Generally, biogenic aragonite precipitates at or close to equilibrium with the oxygen isotope ratios of the ambient water; however, species‐specific equations are needed for accurate and precise water temperature reconstructions .…”

“…δ 18 O measurements in otoliths have successfully been applied to reconstruct life history, migration, habitat use, stock structure, and thermal chronology for myriad species of fish in many different aquatic habitats . Several studies have established linear regression models to estimate ambient water temperatures from δ 18 O otolith values for different fish species occupying dynamic aquatic habitats.…”

First records of three-spined stickleback Gasterosteus aculeatus in Svalbard freshwaters: An effect of climate change?

“…Asgeir Aglen, IMR). We have sampled fish in several watercourses on Svalbard for many years, by gillnets (Svenning 1993(Svenning , 2010, fyke nets (Svenning 1993;Aas 2006), and by electrofishing in both rivers and lakes (Godiksen et al 2012), mainly to study Arctic charr, but other fish species, if present, may also be recorded by these surveys.…”

The effect of lake morphometry on thermal habitat use and growth in Arctic charr populations: implications for understanding climate‐change impacts

“…; Høie & Folkvord ; Godiksen et al. , ). A further advantage of thermal reconstructions is that they overcome the need for extensive monitoring of the thermally heterogeneous habitats used by fish as a result of movement.…”

“…The absence of consistent long-term water temperature data from northern watersheds has hampered abilities to study population-specific temperaturegrowth relationships in Arctic charr under a variety of in-situ conditions, thereby limiting our understanding of interactions between environmental factors that might negatively affect growth. Use of oxygen isotope-based (d 18 O) methods to reconstruct the thermal histories of individual fish from the otolith, however, provides one means of directly linking observed fish growth to temperature in a given environment (e.g., Guiguer et al 2003;Rowell et al 2005;Høie & Folkvord 2006;Godiksen et al 2011Godiksen et al , 2012. A further advantage of thermal reconstructions is that they overcome the need for extensive monitoring of the thermally heterogeneous habitats used by fish as a result of movement.…”